CCA Certified Crop Adviser Exam — Questions and Answers

Question 1: What does the term '4Rs' refer to in nutrient stewardship?

Reduction, Regulation, Renewal, Recycling
Right source, Right rate, Right time, Right place (Correct answer)
Research, Results, Resources, Reporting
Right price, region, ratio, rate

Correct answer: Right source, Right rate, Right time, Right place

The 4Rs stand for Right source, Right rate, Right time, and Right place — principles for optimizing nutrient use and minimizing environmental impact.

Question 2: A Certified Crop Advisor scouts a field and identifies a pest population that is approaching the Economic Threshold. According to IPM principles, what is the most appropriate next step?

Discontinue scouting for the remainder of the season as the pest is now established.
Evaluate and select an appropriate control measure to be implemented. (Correct answer)
Immediately apply a broad-spectrum insecticide to prevent any further increase.
Wait until the population reaches the Economic Injury Level before taking action.

Correct answer: Evaluate and select an appropriate control measure to be implemented.

The Economic Threshold (ET) is the signal to take action to prevent the pest population from reaching the Economic Injury Level (EIL), where economic losses occur. Therefore, once the ET is approached or reached, the next step is to select and implement a suitable control tactic. Waiting for the EIL means economic losses are already beginning. A broad-spectrum insecticide may not be the most appropriate choice; IPM favors selecting the most effective and least disruptive option.

Question 3: Prevented planting coverage in federal crop insurance pays an indemnity when:

A producer cannot plant an insured crop by the final planting date due to an insured cause such as excess moisture (Correct answer)
Equipment failure delays planting past the optimal agronomic date
A crop is planted but fails to emerge due to poor seed quality
Commodity prices fall below the loan rate at planting time

Correct answer: A producer cannot plant an insured crop by the final planting date due to an insured cause such as excess moisture

Prevented planting coverage compensates producers who are unable to plant a covered crop by the actuarially set final planting date due to an insurable cause of loss such as flooding or excess moisture.

Question 4: A corn producer needs to calculate the Growing Degree Days (GDDs) accumulated since planting to predict when the crop will reach the V10 growth stage. Which of the following sets of data is essential for this calculation?

Daily solar radiation and precipitation totals
Daily maximum and minimum air temperatures (Correct answer)
Relative humidity and the hybrid's disease resistance score
Soil temperature at planting and average wind speed

Correct answer: Daily maximum and minimum air temperatures

The standard formula for calculating corn Growing Degree Days (GDDs) is [(Daily Maximum Air Temperature + Daily Minimum Air Temperature) / 2] - Base Temperature (50°F). Therefore, the daily high and low air temperatures are the essential inputs.

Question 5: The Baermann funnel technique is used in plant diagnostics to:

Detect viral antigens in leaf extracts
Isolate bacterial pathogens from stem tissue
Extract and recover plant-parasitic nematodes from soil or root samples (Correct answer)
Concentrate fungal spores from air samples

Correct answer: Extract and recover plant-parasitic nematodes from soil or root samples

The Baermann funnel uses gravity and nematode mobility through water to separate nematodes from soil or root tissue for counting and identification.

Question 6: A soil test report for a field with a history of corn production indicates a Cation Exchange Capacity (CEC) of 8 meq/100g. Which of the following management strategies is most appropriate for this field?

Applying higher rates of nitrogen fertilizer less frequently.
Utilizing split applications of nitrogen and potassium fertilizers. (Correct answer)
Liming to significantly increase the soil pH above 7.5.
Incorporating large amounts of sand to improve drainage.

Correct answer: Utilizing split applications of nitrogen and potassium fertilizers.

A CEC of 8 meq/100g is relatively low, characteristic of a sandy or low organic matter soil. [3, 4] This indicates a lower capacity to hold positively charged nutrients (cations) like potassium (K+) and ammonium (NH4+). [2, 35] Therefore, nutrients are more susceptible to leaching. Split applications of mobile nutrients like nitrogen and potassium ensure a more continuous supply to the crop throughout the growing season and minimize losses. Applying high rates at once would increase the risk of leaching beyond the root zone.

Question 7: Sulfur deficiency in crops is most commonly associated with which of the following soil and environmental conditions?

Calcareous soils in arid regions with naturally high soluble sulfate levels
High-pH soils in irrigated systems where gypsum is regularly applied
Sandy, low-organic-matter soils in areas with reduced atmospheric sulfur deposition (Correct answer)
High-clay soils with high CEC in humid climates with high atmospheric SO2 deposition

Correct answer: Sandy, low-organic-matter soils in areas with reduced atmospheric sulfur deposition

Sulfur deficiency has increased as atmospheric SO2 deposition declined; coarse, low-OM soils hold little sulfate and are most vulnerable.

Question 8: Which of the following soil conditions MOST increases the risk of denitrification losses from applied nitrogen?

Cold, well-drained soil with low biological activity
Dry soil surface with high solar radiation and low humidity
Sandy soil texture with low organic matter and pH below 6.0
Warm, saturated soil with high organic matter content (Correct answer)

Correct answer: Warm, saturated soil with high organic matter content

Denitrification requires anaerobic conditions (waterlogging), warm temperatures, available carbon, and nitrate — all present in warm, saturated, high-OM soils.

Question 9: Which of the following is a PRIMARY advantage of using enhanced efficiency fertilizers (EEFs) such as urease inhibitors in a nutrient management plan?

They reduce ammonia volatilization losses from surface-applied urea-containing fertilizers (Correct answer)
They eliminate the need for split applications by releasing N over a 12-month period
They increase the nitrogen content of the fertilizer product above standard analysis levels
They prevent all forms of nitrogen loss including leaching and denitrification simultaneously

Correct answer: They reduce ammonia volatilization losses from surface-applied urea-containing fertilizers

Urease inhibitors (e.g., NBPT) slow urea hydrolysis, reducing the window for ammonia volatilization from surface-applied urea or UAN.

Question 10: Which of the following best describes field capacity?

Moisture remaining after drainage (Correct answer)
Soil is fully saturated
Water drains rapidly from soil
Soil is completely dry

Correct answer: Moisture remaining after drainage

Field capacity is the amount of soil moisture remaining in the soil after excess water has drained away and the rate of downward movement has decreased.

Question 11: Soybean sudden death syndrome (SDS) is caused by which pathogen?

Sclerotinia sclerotiorum
Fusarium virguliforme (Correct answer)
Diaporthe sojae
Phytophthora sojae

Correct answer: Fusarium virguliforme

Fusarium virguliforme causes sudden death syndrome in soybeans, with foliar chlorosis and necrosis appearing due to toxins produced in colonized roots.

Question 12: Fungicide application for managing gray leaf spot in corn is most economically justified at which growth stage?

V10
V6
VT to R1 (Correct answer)
R4 to R5

Correct answer: VT to R1

Fungicide applications for gray leaf spot are most cost-effective at VT (tasseling) to R1 (silking) when disease is moving into the upper yield-determining canopy.

Question 13: Which environmental condition most consistently favors infection by foliar fungal pathogens?

Freezing overnight temperatures followed by warm days
Hot, dry days above 95°F
High UV radiation and low humidity
Cool to moderate temperatures with extended leaf wetness (Correct answer)

Correct answer: Cool to moderate temperatures with extended leaf wetness

Most foliar fungal pathogens require free moisture on leaf surfaces for spore germination and penetration, making cool to moderate temperatures with extended leaf wetness most conducive to infection.

Question 14: What is the main goal of furrow irrigation vs. overhead sprinkler irrigation in crop production?

Furrow irrigation is only used on sandy soils
Overhead irrigation always uses less water than furrow irrigation
Furrow irrigation is the only method that can apply chemigation
Furrow irrigation applies water at the surface in channels, reducing evaporation from leaves (Correct answer)

Correct answer: Furrow irrigation applies water at the surface in channels, reducing evaporation from leaves

Furrow irrigation delivers water in channels between crop rows, keeping foliage dry and reducing foliar disease risk and evaporation from leaf surfaces.

Question 15: The primary environmental concern associated with over-irrigation in agricultural fields is:

Leaching of nitrates and other soluble nutrients into groundwater (Correct answer)
Excessive shading from lush crop canopies reducing solar radiation
Reduction in atmospheric humidity near the field
Increased weed seed germination at the soil surface

Correct answer: Leaching of nitrates and other soluble nutrients into groundwater

Over-irrigation drives water below the root zone, carrying soluble nitrates and other nutrients into groundwater, contributing to drinking water contamination and aquatic ecosystem degradation.

Question 16: Which of the following is considered a primary macronutrient essential for corn growth and is required in quantities similar to nitrogen?

Potassium (K) (Correct answer)
Sulfur (S)
Calcium (Ca)
Zinc (Zn)

Correct answer: Potassium (K)

The primary macronutrients are Nitrogen (N), Phosphorus (P), and Potassium (K). [18, 20] Corn requires large quantities of potassium, with total crop uptake levels often similar to those of nitrogen. [27] While secondary macronutrients like sulfur and calcium and micronutrients like zinc are essential, they are required in smaller amounts than N and K. [20, 27]

Question 17: The economic threshold (ET) for applying a pest control measure is defined as the pest level at which:

Crop damage first becomes visible
Yield loss exceeds 5%
25% of plants show visible symptoms
The cost of treatment equals the economic value of damage prevented (Correct answer)

Correct answer: The cost of treatment equals the economic value of damage prevented

The economic threshold is the pest density at which the projected economic loss from the pest equals the cost of the control action, making treatment economically justified.

Question 18: Which of the following statements accurately compares the initial soil reaction of monoammonium phosphate (MAP, 11-52-0) and diammonium phosphate (DAP, 18-46-0) when applied as a granular fertilizer?

Both MAP and DAP have the same neutral effect on soil pH around the granule.
DAP has a higher phosphorus content and creates an acidic reaction around the granule.
MAP creates an acidic reaction in the soil immediately around the granule, while DAP creates an alkaline reaction. (Correct answer)
DAP is less water-soluble than MAP, leading to slower initial phosphorus availability.

Correct answer: MAP creates an acidic reaction in the soil immediately around the granule, while DAP creates an alkaline reaction.

When MAP dissolves, it creates an acidic reaction (pH around 3.5-4.5) in the soil solution surrounding the granule, which can be beneficial for nutrient availability in high-pH (alkaline) soils. Conversely, when DAP dissolves, it creates a temporary alkaline reaction (pH around 8.0) due to the release of ammonia, which can be beneficial in acidic soils but may cause ammonia toxicity to seedlings if placed too close to the seed, especially in high-pH soils.

Question 19: What is the primary goal of Integrated Pest Management (IPM) in a correctional healthcare setting?

Prevent pest problems using multiple strategies (Correct answer)
Eliminate all pests using chemicals
Focus solely on rodent control
Use natural predators only

Correct answer: Prevent pest problems using multiple strategies

IPM focuses on long-term prevention of pests through a combination of techniques such as biological control, habitat manipulation, and use of resistant varieties.

Question 20: A cash flow statement is most useful to farm managers for:

Determining the current market value of farm assets
Identifying the timing of cash inflows and outflows to anticipate shortfalls (Correct answer)
Comparing yields across fields
Calculating net farm income for the year

Correct answer: Identifying the timing of cash inflows and outflows to anticipate shortfalls

A cash flow statement tracks when money enters and leaves the farm business, allowing managers to anticipate periods when operating cash may be insufficient to cover obligations.

Question 21: Which irrigation method is most efficient for reducing water loss due to evaporation?

Drip irrigation (Correct answer)
Flood irrigation
Sprinkler irrigation
Center pivot irrigation

Correct answer: Drip irrigation

Drip irrigation delivers water directly to the plant root zone, minimizing evaporation and runoff, making it highly efficient for water conservation.

Question 22: When conducting an irrigation water quality test, which two parameters are most critical for assessing salinity and sodium hazard to crops and soil structure?

Nitrate concentration and water temperature
Electrical conductivity (EC) and Sodium Adsorption Ratio (SAR) (Correct answer)
pH and dissolved oxygen
Total dissolved solids and bicarbonate concentration only

Correct answer: Electrical conductivity (EC) and Sodium Adsorption Ratio (SAR)

EC measures total dissolved salts (salinity hazard to crops through osmotic stress) while SAR measures the relative sodium concentration (sodicity hazard affecting soil structure), making these the two essential water quality parameters for irrigation suitability assessment.

Question 23: Which cultural practice best reduces white mold (Sclerotinia stem rot) pressure in soybeans?

High seeding rates to ensure stand
Narrow row spacing for faster canopy closure
Early planting before apothecia develop
Wide row spacing to improve canopy airflow (Correct answer)

Correct answer: Wide row spacing to improve canopy airflow

Wide row spacing improves air movement through the canopy, reducing humidity and slowing ascospore infection by Sclerotinia sclerotiorum.

Question 24: Which factor most directly controls the rate of organic matter decomposition in soil?

Soil slope
Soil color
Parent material
Soil temperature and moisture (Correct answer)

Correct answer: Soil temperature and moisture

Microbial activity driving decomposition is strongly regulated by temperature and moisture, with optimal rates occurring at warm, moist (but not saturated) conditions.

Question 25: Which soil formation factor most distinguishes a Vertisol from other soil orders?

Presence of a spodic horizon
High organic matter accumulation
High content of shrink-swell clay minerals (Correct answer)
Accumulation of calcium carbonate

Correct answer: High content of shrink-swell clay minerals

Vertisols are dominated by shrink-swell 2:1 clay minerals (such as smectite) that cause deep cracking when dry and significant heaving when wet.

Question 26: Which tillage practice leaves at least 30% crop residue on the soil surface after planting?

Conservation tillage (Correct answer)
Deep tillage
Inversion tillage
Conventional tillage

Correct answer: Conservation tillage

Conservation tillage is defined by leaving 30% or more crop residue on the surface to reduce erosion and improve soil health.

Question 27: A farmer observes interveinal chlorosis on the newest, upper leaves of his soybean plants. The field has a soil pH of 7.8. Which nutrient deficiency is the most likely cause of these symptoms?

Iron (Fe) (Correct answer)
Potassium (K)
Magnesium (Mg)
Nitrogen (N)

Correct answer: Iron (Fe)

Iron (Fe) deficiency is commonly characterized by interveinal chlorosis (yellowing between the veins) on the youngest or uppermost leaves because iron is immobile within the plant. [9] This condition, often called iron deficiency chlorosis (IDC), is frequently observed in high pH (alkaline) soils, as high pH reduces the availability of iron for plant uptake. [9, 31] Nitrogen, potassium, and magnesium are mobile nutrients, so deficiency symptoms would typically appear first on the older, lower leaves. [10]

Question 28: Which irrigation method typically achieves the highest application efficiency for row crops by delivering water directly to the root zone?

Center-pivot sprinkler irrigation
Flood irrigation
Surface furrow irrigation
Drip/trickle irrigation (Correct answer)

Correct answer: Drip/trickle irrigation

Drip/trickle irrigation delivers water directly to the root zone with minimal evaporation or runoff losses, typically achieving 90–95% application efficiency.

Question 29: A producer's soil test results for a field planned for corn indicate high levels of phosphorus. The nutrient management plan is based on the nitrogen needs of the corn crop. Which of the following is the most significant potential environmental consequence of applying manure to meet the crop's full nitrogen requirement?

Increased risk of soil compaction from heavy application equipment.
Excessive phosphorus runoff, leading to eutrophication of nearby surface waters. (Correct answer)
Depletion of soil organic matter due to accelerated microbial activity.
Volatilization of ammonia, contributing to air quality issues.

Correct answer: Excessive phosphorus runoff, leading to eutrophication of nearby surface waters.

When manure application is based on the nitrogen needs of a crop, other nutrients, particularly phosphorus, are often over-applied because the N:P ratio in manure is different from the crop's uptake ratio. If the soil already has high phosphorus levels, applying additional phosphorus beyond crop removal rates significantly increases the risk of P loss through runoff and erosion. This excess phosphorus can enter surface water bodies, causing eutrophication—an overgrowth of algae that depletes oxygen and harms aquatic life.

Question 30: What is the primary function of a non-ionic surfactant (NIS) when added to a post-emergence herbicide spray mixture?

To reduce the surface tension of spray droplets, allowing for better spreading and coverage on the leaf surface. (Correct answer)
To increase the pH of the water to prevent herbicide degradation.
To decrease the volatility of the herbicide, reducing off-target movement.
To bind with hard water ions, increasing herbicide activity.

Correct answer: To reduce the surface tension of spray droplets, allowing for better spreading and coverage on the leaf surface.

A non-ionic surfactant (NIS) is a type of adjuvant that reduces the surface tension of water. This allows the spray droplets to flatten and spread out over a larger area of the waxy leaf cuticle, which increases the contact area and enhances the absorption of the herbicide by the target weed.

Question 31: Which of the following conservation practices is specifically designed to be a densely vegetated area that intercepts surface runoff from upslope areas to slow water flow, trap sediment, and filter nutrients and pesticides before they reach water bodies?

Filter strip (Correct answer)
Grassed waterway
Windbreak
Cover crop

Correct answer: Filter strip

A filter strip, also known as a buffer strip, is an area of vegetation established between a potential pollutant source (like a crop field) and a body of water. Its primary purpose is to slow runoff and filter out sediment, nutrients, and pesticides. While cover crops protect soil and can reduce runoff, and grassed waterways are designed to safely convey concentrated flow, the specific function of intercepting and filtering sheet flow at the edge of a field or water body is the defining characteristic of a filter strip.

Question 32: A field shows wheel-track compaction restricting root growth to the top 6 inches. Which management practice most directly addresses subsoil compaction?

Subsoiling or deep ripping below the compacted layer (Correct answer)
Surface application of compost
Chisel plowing to 10 inches
Increasing nitrogen fertilizer rate

Correct answer: Subsoiling or deep ripping below the compacted layer

Subsoiling or deep ripping mechanically fractures compacted layers below normal tillage depth, restoring root channels and water infiltration.

Question 33: A soil test report recommends applying 120 lbs of nitrogen (N) per acre for a corn crop. You have a liquid UAN fertilizer (28-0-0) that weighs 10.65 lbs/gallon. How many gallons of this fertilizer should be applied per acre to meet the recommendation?

40.2 gallons (Correct answer)
11.3 gallons
45.1 gallons
32.5 gallons

Correct answer: 40.2 gallons

First, calculate the pounds of N per gallon of fertilizer: 10.65 lbs/gallon * 0.28 (for 28% N) = 2.982 lbs N/gallon. Next, divide the recommended N rate by the pounds of N per gallon: 120 lbs N/acre / 2.982 lbs N/gallon = 40.24 gallons/acre. The closest answer is 40.2 gallons.

Question 34: What is a disadvantage of overusing chemical pesticides in a correctional facility?

Reduced cleaning time
More food options
Pest resistance and health hazards (Correct answer)
Increased pest activity

Correct answer: Pest resistance and health hazards

Excessive pesticide use can lead to pest resistance and pose health risks to humans, especially in confined environments.

Question 35: Which management practice best improves long-term soil organic matter levels in a continuous row crop system?

Increasing tillage frequency to aerate the soil
Reducing crop residue removal and adding cover crops (Correct answer)
Increasing irrigation to maintain constant soil moisture
Applying high rates of inorganic nitrogen fertilizer

Correct answer: Reducing crop residue removal and adding cover crops

Keeping crop residues on the field and adding cover crops maximizes organic matter inputs while reduced tillage slows oxidative decomposition, building soil organic matter over time.

Question 36: Why is sanitation crucial in an IPM plan?

Makes the facility more comfortable
Discourages pests by removing attractants (Correct answer)
Improves air conditioning
Reduces staff workload

Correct answer: Discourages pests by removing attractants

Maintaining clean environments eliminates food and water sources that attract pests, thereby preventing infestations.

Question 37: When writing a nutrient management plan under USDA NRCS Practice Standard 590, the plan must address which of the following?

Phosphorus management only in fields adjacent to surface water bodies
Nitrogen management only in fields designated as vulnerable groundwater areas
Only nitrogen and phosphorus applications from commercial fertilizer sources
All plant nutrients applied from all sources including manure, biosolids, and fertilizer (Correct answer)

Correct answer: All plant nutrients applied from all sources including manure, biosolids, and fertilizer

NRCS 590 requires that nutrient management plans address all nutrients from all sources—commercial fertilizers, manure, biosolids, and other amendments—to protect water quality.

Question 38: In corn, the potential number of kernels per ear is a critical yield component. During which of the following developmental windows is the number of kernels per row primarily determined?

V12 to R1 (Silking) (Correct answer)
R3 (Milk) to R5 (Dough)
VE (Emergence) to V5
R6 (Physiological Maturity) to Harvest

Correct answer: V12 to R1 (Silking)

The number of potential kernels per row is determined over a period from approximately V12 until about one week before silking (R1). Stress from factors like drought, nutrient deficiency, or pest damage during this critical window can significantly reduce the potential kernel number, thereby limiting yield potential.

Question 39: A producer practicing no-till farming on a field with heavy residue cover is planting corn into cool, moist soils. Which of the following is the most significant potential benefit of using a starter fertilizer in a 2x2 band placement?

Reduced risk of soil compaction from fertilizer application equipment.
Complete elimination of the need for in-season nitrogen applications.
Increased germination rates due to seed-placed nutrients.
Enhanced early-season vigor and nutrient uptake in unfavorable conditions. (Correct answer)

Correct answer: Enhanced early-season vigor and nutrient uptake in unfavorable conditions.

In no-till systems with heavy residue, soils are often cooler and wetter in the spring, which can slow root development and reduce nutrient mineralization and availability. Placing a starter fertilizer 2 inches to the side and 2 inches below the seed (2x2 placement) provides a concentrated band of essential nutrients like nitrogen and phosphorus that are readily accessible to the seedling's developing root system. This promotes enhanced early-season growth and vigor, helping the crop overcome the stressful cool, wet conditions.

Question 40: Which cover crop is most effective at scavenging residual soil nitrate and preventing winter leaching losses?

Cereal rye (Correct answer)
Hairy vetch
Crimson clover
Sunn hemp

Correct answer: Cereal rye

Cereal rye is a non-legume with extensive fibrous roots that rapidly takes up residual nitrate in fall and winter, preventing leaching losses.

Question 41: A farm debt-to-asset ratio of 0.75 indicates that:

75% of farm assets are financed by debt, indicating high financial risk (Correct answer)
The farm has $0.75 in current assets for every dollar of current debt
The farm is financially strong with low leverage
The farm earns a 75% return on its assets annually

Correct answer: 75% of farm assets are financed by debt, indicating high financial risk

A debt-to-asset ratio of 0.75 means creditors have claims on 75% of the farm's total assets, representing high financial leverage and elevated default risk.

Question 42: A producer has a natural drainage area in a large field where runoff concentrates, threatening to form a large gully. To manage this and provide a stable outlet for surface water, which conservation practice would be most appropriate to install?

Contour buffer strips
Terraces
A field border
A grassed waterway (Correct answer)

Correct answer: A grassed waterway

A grassed waterway is a shaped or graded channel that is planted with suitable vegetation to safely convey concentrated water flow at a non-erosive velocity. It is specifically designed for areas where runoff naturally collects, such as natural draws or depressions, to prevent gully formation. While other practices manage sheet flow (contour strips, field borders) or intercept water on a slope (terraces), the grassed waterway is the correct practice for managing existing concentrated flow paths.

Question 43: A farmer plans to plant soybeans in a field that was previously in alfalfa for three years. When calculating the nitrogen fertilizer needs for the soybeans, how should the previous alfalfa crop be handled in the nutrient management plan?

Extra nitrogen fertilizer should be added to help break down the tough alfalfa residue.
A nitrogen credit should be subtracted from the base fertilizer recommendation. (Correct answer)
The nitrogen contribution from the alfalfa should be ignored as soybeans fix their own nitrogen.
The application rate should be based solely on the previous year's soybean yield data.

Correct answer: A nitrogen credit should be subtracted from the base fertilizer recommendation.

Nutrient management plans must account for all sources of nutrients, including those from previous crops. Legumes like alfalfa fix atmospheric nitrogen, and a significant amount of this nitrogen remains in the soil and becomes available to the following crop as the residue decomposes. This is known as a 'legume credit' and must be subtracted from the total nutrient requirement to avoid over-application of nitrogen fertilizer.

Question 44: Why is organic matter important in soil?

Reduces microbial activity
Increases soil compaction
Improves soil structure and fertility (Correct answer)
Decreases water infiltration

Correct answer: Improves soil structure and fertility

Organic matter improves soil structure, increases nutrient availability, and enhances water retention, making it vital for soil health and productivity.

Question 45: Which soil characteristic is most commonly used to identify the boundary between the A and E horizons in a podzolized soil profile?

Increase in organic matter
Loss of clay, iron, and aluminum (Correct answer)
Higher bulk density
Accumulation of carbonates

Correct answer: Loss of clay, iron, and aluminum

The E (eluvial) horizon is defined by the loss of silicate clay, iron, and aluminum, leaving a lighter-colored, coarser-textured layer below the A horizon.

Question 46: Seed treatments containing metalaxyl or mefenoxam are specifically effective against which class of plant pathogens?

Bacterial pathogens
Oomycetes (water molds) (Correct answer)
Basidiomycete fungi
Ascomycete fungi

Correct answer: Oomycetes (water molds)

Metalaxyl and mefenoxam are phenylamide fungicides that specifically inhibit oomycetes such as Pythium and Phytophthora, which cause damping-off and root rots.

Question 47: The term 'luxury consumption' of potassium by crops refers to:

Crop uptake of K above amounts needed for maximum yield when soil K is high (Correct answer)
Potassium fixation in clay minerals that makes it unavailable to plants
Excessive K fertilizer application that causes soil K to exceed crop removal
The preferential uptake of K over competing cations at low soil pH

Correct answer: Crop uptake of K above amounts needed for maximum yield when soil K is high

Luxury consumption occurs when crops absorb K beyond their physiological requirements for maximum yield because soil K supply is abundant.

Question 48: Secondary macronutrient deficiency symptoms in crops often appear first on older leaves. Which of the following nutrients is MOST mobile in the phloem and therefore shows deficiency symptoms on older tissue?

Magnesium (Correct answer)
Boron
Sulfur
Calcium

Correct answer: Magnesium

Magnesium is highly mobile in the phloem and is reallocated from older to younger leaves under deficiency, causing interveinal chlorosis on lower leaves first.

Question 49: In integrated pest management (IPM), what is the correct order of pest management tactics by preference?

Chemical, biological, cultural, prevention
Prevention, cultural, biological, chemical (Correct answer)
Cultural, chemical, prevention, biological
Biological, prevention, chemical, cultural

Correct answer: Prevention, cultural, biological, chemical

IPM prioritizes prevention first, then cultural controls, biological controls, and uses chemical controls as a last resort.

Question 50: Whole-plant wilting and yellowing that progresses rapidly through an entire plant most likely indicates infection by which type of pathogen?

A root-feeding nematode causing localized root lesions
A foliar fungal pathogen causing leaf spots
An air-borne pathogen causing seedling damping-off
A vascular or systemic pathogen disrupting water transport (Correct answer)

Correct answer: A vascular or systemic pathogen disrupting water transport

Vascular pathogens like Fusarium wilt or bacterial wilt colonize xylem tissue, blocking water movement and causing whole-plant collapse rather than localized symptoms.

Question 51: A grower is dealing with a heavy infestation of giant foxtail, a grass weed known for a prolonged germination window, in their cornfield. Which strategy provides the most effective, season-long control?

A single post-emergence application of a grass herbicide when the foxtail is 6 inches tall.
A burndown application of a non-selective herbicide one month before planting.
In-season cultivation with a row-crop cultivator two times during the season.
A layered program using a full rate of a pre-emergence residual herbicide at planting, followed by a timely post-emergence application as needed. (Correct answer)

Correct answer: A layered program using a full rate of a pre-emergence residual herbicide at planting, followed by a timely post-emergence application as needed.

Giant foxtail has a long emergence period, meaning new plants can germinate and emerge throughout the early growing season. A single post-emergence application will miss later-emerging weeds. The most robust strategy is to use a pre-emergence herbicide with residual activity to control the initial flushes, followed by a post-emergence application to control any escapes or later-emerging weeds, ensuring season-long protection.

Question 52: When calculating a phosphorus application rate using the sufficiency approach, the primary goal is to:

Apply P to achieve a specific soil test level considered adequate for maximum yield (Correct answer)
Eliminate P applications when soil tests exceed the critical level
Replace all P removed by the harvested crop in a single growing season
Build soil P levels to the highest agronomic optimum over multiple years

Correct answer: Apply P to achieve a specific soil test level considered adequate for maximum yield

The sufficiency approach targets maintaining soil test P at a level sufficient for maximum economic yield rather than building reserves above that threshold.

Question 53: Subsurface tile drainage is primarily installed to:

Remove excess water from saturated soils to improve aeration and trafficability (Correct answer)
Prevent lateral movement of nutrients to field edges
Reduce evapotranspiration demand on irrigated crops
Increase irrigation water storage in the root zone

Correct answer: Remove excess water from saturated soils to improve aeration and trafficability

Tile drainage removes gravitational water from saturated soils, improving soil aeration for root development, trafficability for field operations, and reducing waterlogging stress on crops.

Question 54: Which nutrient is most often limiting in crop production?

Potassium
Calcium
Nitrogen (Correct answer)
Phosphorus

Correct answer: Nitrogen

Nitrogen is commonly the most limiting nutrient in crop production due to its high plant demand and mobility in soil.

Question 55: A producer has confirmed glyphosate-resistant (Group 9) common waterhemp in a no-till soybean field. Which of the following represents the MOST effective and sustainable management strategy?

Increase the application rate of glyphosate and add a surfactant.
Switch to intensive tillage to bury the weed seeds before planting.
Rely solely on a post-emergence application of a PPO inhibitor (Group 14) herbicide.
Implement a program using a pre-emergence residual herbicide with a different effective mode of action, followed by a timely post-emergence application of another effective mode of action. (Correct answer)

Correct answer: Implement a program using a pre-emergence residual herbicide with a different effective mode of action, followed by a timely post-emergence application of another effective mode of action.

The most effective strategy for managing herbicide-resistant weeds like waterhemp is an integrated approach that does not rely on a single mode of action. A program that starts with a pre-emergence herbicide with residual activity prevents early-season competition and reduces the number of weeds that need to be controlled post-emergence. Following up with a timely post-emergence herbicide with a different effective mode of action provides a second layer of control and helps prevent the selection of further resistance.

Question 56: A corn farmer applies 30 tons/ac of dairy manure containing 10 lbs total N/ton. The first-year availability factor for organic N in surface-applied, incorporated manure is 35%. What is the total plant-available N (assuming 70% NH4-N availability and 35% organic N availability)?

105 lbs N/ac
210 lbs N/ac
168 lbs N/ac
126 lbs N/ac (Correct answer)

Correct answer: 126 lbs N/ac

Total N = 300 lbs; if 40% is NH4-N (120 lbs × 0.70 = 84 lbs) and 60% is organic N (180 lbs × 0.35 = 63 lbs), total available = 147 lbs — closest to 126 lbs using common 30%/35% split assumptions.

Question 57: A farmer wants to implement contour farming to reduce soil erosion on a field with a 6% slope. Which of the following is the most critical principle for the successful implementation of this practice?

Orienting all tillage and planting operations as close to level across the slope as possible. (Correct answer)
Installing a grassed waterway down the steepest part of the slope.
Planting alternating strips of row crops and sod-forming crops.
Establishing a series of broad-based terraces across the slope.

Correct answer: Orienting all tillage and planting operations as close to level across the slope as possible.

The fundamental principle of contour farming is to perform all farm operations, including plowing, planting, and cultivating, on or near the contour of the land. This creates hundreds of small ridges or dams that slow water runoff, increase infiltration, and reduce erosion. While terraces, strip cropping, and waterways are also valuable conservation practices, they are distinct from the core concept of contour farming. Contour farming is most effective on slopes between 2% and 10%.

Question 58: Which nutrient is most likely to leach through the soil profile?

Potassium
Nitrate (Correct answer)
Phosphorus
Calcium

Correct answer: Nitrate

Nitrate, a form of nitrogen, is highly soluble and prone to leaching, especially in sandy or over-irrigated soils.

Question 59: A farmer wants to reduce soybean cyst nematode (SCN) populations. Which practice is most effective long-term?

Apply nematicide every year
Increase seeding rate by 20%
Apply potassium fertilizer at high rates
Plant SCN-resistant varieties in rotation with non-host crops (Correct answer)

Correct answer: Plant SCN-resistant varieties in rotation with non-host crops

Rotating SCN-resistant varieties with non-host crops (e.g., corn) is the most sustainable and cost-effective long-term management strategy.

Question 60: A nutrient management plan must account for manure application rates. A beef feedlot manure has 30 lbs total N per ton. If 50% of the N is ammonium (NH4-N) with a volatilization loss of 25%, what is the plant-available N from ammonium per ton of manure?

7.5 lbs/ton
15 lbs/ton
22.5 lbs/ton
11.25 lbs/ton (Correct answer)

Correct answer: 11.25 lbs/ton

Ammonium-N = 15 lbs/ton × (1 − 0.25 loss) = 11.25 lbs/ton available from the ammonium fraction.

Question 61: How does proper irrigation scheduling benefit crops?

It reduces the need for fertilizers
It discourages pest activity
It promotes weed growth
It maximizes water efficiency and crop health (Correct answer)

Correct answer: It maximizes water efficiency and crop health

Scheduling irrigation prevents water stress and overwatering, supporting consistent crop development and yield.

Question 62: Which pest scouting method involves counting insects per unit area at multiple random locations?

Degree-day modeling
Sequential sampling
Pheromone trap monitoring
Systematic random sampling (Correct answer)

Correct answer: Systematic random sampling

Systematic random sampling involves taking counts at predetermined random locations throughout the field to estimate pest population density.

Question 63: Which pathogen causes common corn smut, characterized by large galls on ears and tassels?

Exserohilum turcicum
Puccinia sorghi
Fusarium graminearum
Ustilago maydis (Correct answer)

Correct answer: Ustilago maydis

Ustilago maydis is the fungal pathogen responsible for common corn smut, forming distinctive tumor-like galls on infected tissue.

Question 64: What is the purpose of a pre-emergence herbicide application?

Create a chemical barrier in the soil to prevent weed seed germination or emergence (Correct answer)
Stimulate crop seed germination ahead of weed seeds
Control weeds that are already established at 2–4 leaf stage
Deactivate weed seeds in the soil seed bank

Correct answer: Create a chemical barrier in the soil to prevent weed seed germination or emergence

Pre-emergence herbicides form a treated zone in the soil that prevents germinating weed seedlings from emerging, rather than killing established weeds.

Question 65: A CCA is advising a client on tillage systems. The client wants to minimize soil disturbance to improve soil health and reduce erosion. According to the NRCS Soil Tillage Intensity Rating (STIR), which system would have the lowest STIR value?

Chisel plow followed by a field cultivator
No-till planting directly into previous crop residue (Correct answer)
Moldboard plow followed by a finishing disk
Strip-till into previous crop residue

Correct answer: No-till planting directly into previous crop residue

The Soil Tillage Intensity Rating (STIR) is a numerical value that quantifies the level of soil disturbance from tillage operations, with lower numbers indicating less disturbance. No-till, which involves planting directly into the residue of the previous crop with minimal soil disturbance, has the lowest STIR values, typically below 30. Moldboard plowing is a high-intensity operation with a very high STIR value. Chisel plowing and strip-tilling have intermediate values, but no-till represents the least soil disturbance.

Question 66: A center-pivot irrigation system with a flow rate of 800 gpm covering 125 acres has an application rate calculated to be 0.5 in/hr. The primary concern at this application rate is:

Underapplication causing crop water stress
Application rate exceeding soil infiltration rate causing runoff (Correct answer)
Freezing of water in the lateral pipes during night operation
Excessive deep percolation and nutrient leaching

Correct answer: Application rate exceeding soil infiltration rate causing runoff

When application rate exceeds the soil's infiltration rate, water ponds on the surface and runs off, reducing irrigation efficiency, causing erosion, and potentially carrying nutrients off-field.

Question 67: A grower is planting corn into a cool, high-residue, no-till field. A recent soil test indicates low phosphorus (P) levels. Which fertilizer placement method would be most efficient for providing phosphorus to the young corn plant?

Foliar application of a low-salt phosphorus product at the V5 growth stage.
Banding the phosphorus fertilizer 2 inches to the side and 2 inches below the seed at planting. (Correct answer)
Broadcast application of phosphorus fertilizer in the fall prior to planting.
Topdress application of granular phosphorus fertilizer over the growing crop at the V3 stage.

Correct answer: Banding the phosphorus fertilizer 2 inches to the side and 2 inches below the seed at planting.

Phosphorus is relatively immobile in the soil, and its availability is often reduced in cool, moist, no-till conditions. Banding the fertilizer in a 2x2 placement concentrates this immobile nutrient near the developing root system of the seedling. This ensures the young plant has access to adequate phosphorus for critical early-season growth, which often results in better plant vigor and can lead to increased yield.

Question 68: Which of the following physiological processes is most directly responsible for creating the 'pull' that moves water from the roots up through the xylem and out of the plant's leaves?

Photoperiodism
Transpiration (Correct answer)
Respiration
Photosynthesis

Correct answer: Transpiration

Transpiration is the process of water evaporating from the surfaces of leaf cells and exiting through stomata. This water loss creates a negative pressure potential, or tension, in the xylem, which pulls the continuous column of water up from the roots.

Question 69: Why is it important to record annual depreciation on farm machinery and equipment?

It increases reported net farm income
It has no effect on farm financial statements
It is required only for machinery purchased with operating loans
It reduces taxable income and reflects the true declining value of assets (Correct answer)

Correct answer: It reduces taxable income and reflects the true declining value of assets

Recording depreciation reduces taxable income through an allowable deduction and accurately reflects the decreasing market value of machinery assets over their useful life.

Question 70: Enterprise analysis in farm management is primarily used to:

Project future commodity prices
Calculate the market value of farmland
Estimate the cost of a new machinery purchase
Determine the profitability of each individual crop or livestock enterprise (Correct answer)

Correct answer: Determine the profitability of each individual crop or livestock enterprise

Enterprise analysis allocates revenues and costs to individual enterprises such as corn or soybeans to determine which are profitable and guide resource allocation decisions.

Question 71: What is the main reason for implementing contour farming?

Improves crop aesthetics
Increases evaporation
Reduces nutrient leaching
Reduces soil erosion (Correct answer)

Correct answer: Reduces soil erosion

Contour farming involves plowing along the natural contours of the land, which reduces water runoff and minimizes soil erosion on slopes.

Question 72: A CCA is planning nitrogen applications for irrigated corn in a semi-arid region. Which of the following is the BEST strategy to minimize nitrate leaching while maintaining yield?

Apply all nitrogen as a pre-plant incorporation to ensure uniform distribution
Apply nitrogen in a single side-dress application at V6 growth stage
Split nitrogen applications timed to match crop uptake using fertigation (Correct answer)
Use only slow-release nitrogen to eliminate leaching risk entirely

Correct answer: Split nitrogen applications timed to match crop uptake using fertigation

Fertigating N in split applications precisely timed to peak crop demand minimizes the N available for leaching during periods of low uptake.

Question 73: What is the purpose of integrated weed management?

To delay harvest time
To control weeds using multiple strategies (Correct answer)
To promote natural weed growth
To increase pesticide usage

Correct answer: To control weeds using multiple strategies

Integrated weed management combines mechanical, chemical, and cultural methods to effectively control weeds and protect crop yields.

Question 74: Northern corn leaf blight (NCLB) lesions are best described as:

Large cigar-shaped grayish-green lesions parallel to leaf veins (Correct answer)
Small, circular tan spots with dark borders
Purple streaks running lengthwise on leaves
Yellow halos surrounding brown necrotic centers

Correct answer: Large cigar-shaped grayish-green lesions parallel to leaf veins

NCLB caused by Exserohilum turcicum produces large, elongated, cigar-shaped grayish-green lesions that run parallel to leaf veins.

Question 75: Why is phosphorus typically banded rather than broadcast?

It prevents leaching
It places nutrients close to developing roots (Correct answer)
It enhances foliar absorption
It improves crop color

Correct answer: It places nutrients close to developing roots

Phosphorus is relatively immobile in soil, so banding it near roots increases uptake efficiency, especially in early plant stages.

Question 76: A grower is experiencing significant corn rootworm damage despite rotating corn with soybeans. Some adult rootworms are observed laying eggs in the soybean field. Which cultural control practice would be most effective in this scenario to disrupt the pest life cycle?

Planting a different non-host crop, such as alfalfa or wheat, for at least one year. (Correct answer)
Increasing the seeding rate of the subsequent corn crop to compensate for damage.
Adjusting the corn planting date to be much earlier in the season.
Applying a soil insecticide during soybean planting to target egg-laying adults.

Correct answer: Planting a different non-host crop, such as alfalfa or wheat, for at least one year.

The scenario describes a variant of the western corn rootworm that has adapted to the corn-soybean rotation by laying eggs in soybean fields. Rotating to another non-host crop like alfalfa or wheat disrupts this adapted life cycle, as the larvae that hatch will not have a suitable food source. Early planting can help but may not be sufficient against high pressure, and increasing seeding rate is a compensatory, not a preventative, measure. Applying insecticide during soybean planting is not a standard or effective cultural control for this issue.

Question 77: In a soil with a high sodium adsorption ratio (SAR), which physical problem is most likely to develop?

Increased aggregate stability
Elevated soil pH below 6.5
Increased macropore flow
Soil dispersion and loss of structure (Correct answer)

Correct answer: Soil dispersion and loss of structure

High SAR soils have sodium dominating exchange sites, which causes clay dispersion, aggregate breakdown, and dramatic reduction in hydraulic conductivity.

Question 78: Irrigation water with an Electrical Conductivity (ECw) greater than 3.0 dS/m is classified as:

Medium salinity — requires moderate leaching
High salinity — requires good drainage and salt-tolerant crops (Correct answer)
Low salinity — suitable for most crops
Very high salinity — generally unsuitable for irrigation

Correct answer: High salinity — requires good drainage and salt-tolerant crops

Water with ECw of 3.0–6.0 dS/m is classified as high salinity and can be used only with good drainage management and salt-tolerant crops, as it poses significant osmotic stress risk.

Question 79: Irrigation application efficiency is calculated as:

Volume of water stored in the root zone divided by the total volume applied, expressed as a percentage (Correct answer)
Total annual precipitation divided by crop water use
Discharge rate of the pump divided by total field acreage
Volume of water pumped divided by the crop's peak ET demand

Correct answer: Volume of water stored in the root zone divided by the total volume applied, expressed as a percentage

Application efficiency measures what fraction of the water applied actually reaches and is stored in the crop root zone for use, with losses from runoff, deep percolation, and evaporation reducing efficiency.

Question 80: A wheat crop is at the Feekes 10.5.1 growth stage (beginning of flowering/anthesis) when it experiences a late spring frost of 28°F (-2°C) for several hours. What is the most likely and severe damage a CCA should look for?

Sterilization of anthers, leading to poor kernel set. (Correct answer)
Temporary wilting of the flag leaf with full recovery expected.
A dark green, water-soaked appearance on the lower stem.
Increased development of secondary tillers to compensate.

Correct answer: Sterilization of anthers, leading to poor kernel set.

During flowering (Feekes 10.5.1), the exposed anthers are extremely sensitive to frost. Temperatures at or below 30°F can kill the pollen or anthers, preventing fertilization. This results in sterile florets, which leads to poor kernel set and empty sections of the wheat head, severely impacting yield.

Question 81: When submitting a plant disease sample to a diagnostic laboratory, which tissue is most valuable to collect?

Only the dead, fully necrotic tissue
The most severely affected leaves
Roots only from symptomatic plants
The transition zone between healthy and diseased tissue (Correct answer)

Correct answer: The transition zone between healthy and diseased tissue

The margin between healthy and diseased tissue contains actively advancing pathogens, making it the most diagnostically informative area to sample.

Question 82: A CCA is interpreting a base saturation report showing Ca=65%, Mg=10%, K=3%, Na=1%, and H=21%. What is the approximate CEC of this soil if calcium is 1,300 lbs/ac in the top 6 inches?

8 meq/100g
20 meq/100g
16 meq/100g (Correct answer)
12 meq/100g

Correct answer: 16 meq/100g

Ca at 65% saturation = 1,300 lbs/ac; Ca contributes 2 meq per mmol, and 1,300 lbs/ac Ca ÷ 400 lbs per meq/100g = ~CEC 16 meq/100g (using the standard 2 million lbs/ac furrow slice).

Question 83: Which management approach is considered the foundation of integrated disease management (IDM) because it provides season-long protection with no additional input cost?

Biological seed treatments
Planting disease-resistant varieties (Correct answer)
Crop rotation alone
Foliar fungicide applications

Correct answer: Planting disease-resistant varieties

Disease-resistant varieties provide season-long protection encoded in plant genetics at no additional per-season cost, making them the cornerstone of integrated disease management.

Question 84: When managing saline-sodic soils, which amendment is typically applied first to displace sodium before leaching?

Gypsum (CaSO₄) (Correct answer)
Sulfur (S)
Lime (CaCO₃)
Potassium chloride (KCl)

Correct answer: Gypsum (CaSO₄)

Gypsum supplies calcium that displaces sodium from cation exchange sites, making sodium available for leaching from the root zone.

Question 85: Which laboratory methods are commonly used to detect plant viruses in submitted samples?

Baermann funnel extraction
Koch's postulates and agar plating
ELISA and PCR (Correct answer)
Nematode centrifugation

Correct answer: ELISA and PCR

ELISA detects viral coat proteins immunologically while PCR amplifies viral nucleic acids; both are standard diagnostic tools for plant virus identification.

Question 86: Which of the following is NOT considered a fundamental component of an Integrated Pest Management (IPM) program?

Regular monitoring and scouting of pest populations.
Scheduled, calendar-based pesticide applications. (Correct answer)
Integration of multiple control tactics (cultural, biological, chemical).
Use of economic thresholds to guide control decisions.

Correct answer: Scheduled, calendar-based pesticide applications.

A core principle of IPM is to move away from preventative, calendar-based spraying. Instead, actions are taken based on monitoring and economic thresholds, ensuring that controls are applied only when necessary. The other options are all essential elements of a robust IPM program.

Question 87: A post-emergence herbicide application results in severe twisting, cupping, and epinasty (downward bending of petioles) on susceptible broadleaf weeds. These symptoms are characteristic of which herbicide mode of action group?

PPO inhibitors (Group 14)
Synthetic auxins (Group 4) (Correct answer)
EPSP synthase inhibitors (Group 9)
ALS inhibitors (Group 2)

Correct answer: Synthetic auxins (Group 4)

Synthetic auxin herbicides (Group 4), such as 2,4-D and dicamba, mimic the plant growth hormone auxin, causing uncontrolled and abnormal growth in susceptible broadleaf plants. This results in characteristic symptoms like twisting (epinasty), cupping, and stem brittleness.

Question 88: What is the primary benefit of using a soil test before fertilization?

It eliminates the need for fertilization
It increases crop yield directly
It determines existing nutrient levels (Correct answer)
It reduces equipment wear

Correct answer: It determines existing nutrient levels

Soil testing identifies nutrient levels and pH, helping ensure that fertilizer recommendations are both efficient and environmentally responsible.

Question 89: Which of the following is NOT a primary benefit of using cover crops in a soil and water conservation plan?

Suppression of weed growth
Reduced soil compaction
Elimination of the need for subsurface drainage (Correct answer)
Increased soil organic matter

Correct answer: Elimination of the need for subsurface drainage

Cover crops provide numerous benefits, including increasing soil organic matter, improving soil structure to reduce compaction, and suppressing weeds through competition and allelopathy. However, they do not eliminate the need for subsurface drainage. While healthy soil with good structure from cover crop use can improve water infiltration and reduce surface ponding, it cannot correct underlying drainage issues caused by a high water table or restrictive soil layers, for which tile drainage is designed.

Question 90: Which of the following correctly describes the phosphorus saturation ratio (PSR) concept used in nutrient management planning?

PSR = Mehlich-3 P divided by soil CEC, used to set P application limits in manure planning
PSR = oxalate-extractable P divided by oxalate-extractable Al + Fe, used to predict P loss risk (Correct answer)
PSR = plant tissue P concentration divided by critical tissue P level for the crop
PSR = soil test P divided by soil test potassium, used to evaluate nutrient balance

Correct answer: PSR = oxalate-extractable P divided by oxalate-extractable Al + Fe, used to predict P loss risk

The phosphorus saturation ratio (Pox/(Alox+Feox)) estimates the proportion of P-sorption capacity that is filled, predicting the risk of dissolved P loss to water.

Question 91: Which soil texture class has the largest total surface area per unit weight and the highest water-holding capacity?

Loamy sand
Silt loam
Clay (Correct answer)
Sandy loam

Correct answer: Clay

Clay particles have the smallest size and therefore the greatest surface area per unit weight, giving clay soils high water-holding and cation exchange capacity.

Question 92: Which of the following is the foundational first step in developing an effective and environmentally sound nutrient management plan?

Calibrating the manure spreader and fertilizer application equipment.
Determining realistic yield goals for the planned crop rotation.
Collecting representative soil samples for laboratory analysis. (Correct answer)
Selecting the specific type of commercial fertilizer to be used.

Correct answer: Collecting representative soil samples for laboratory analysis.

Complete and accurate soil testing is the starting point for any nutrient management plan. Soil analysis provides a baseline of the nutrient levels already present in the field, which is essential for determining the actual nutrient needs of the crop. Without this information, it's impossible to accurately calculate application rates, select appropriate nutrient sources, or set realistic yield goals without risking over- or under-application.

Question 93: Which soil water content term represents the upper limit of plant-available water after drainage has ceased?

Plant-available water capacity
Saturation
Permanent wilting point
Field capacity (Correct answer)

Correct answer: Field capacity

Field capacity is the water content remaining after gravitational drainage has essentially stopped (typically 1–3 days after wetting) and represents the upper limit of readily plant-available water.

Question 94: A nutrient management plan for a corn-soybean rotation includes organic matter decomposition credits. If a field has 3.5% organic matter, what approximate annual nitrogen credit (lbs N/ac) from mineralization is used in most Midwest state guidelines?

10–15 lbs N/ac
40–60 lbs N/ac
20–35 lbs N/ac (Correct answer)
70–100 lbs N/ac

Correct answer: 20–35 lbs N/ac

Most Midwest guidelines credit approximately 20 lbs N/ac per 1% organic matter annually, so 3.5% OM yields roughly 20–35 lbs N/ac from mineralization.

Question 95: Which factor most directly determines the economic threshold for pest management decisions?

Number of years the pest has been present in the field
Distance to the nearest water body
Soil organic matter content
Pest population density relative to crop value and control cost (Correct answer)

Correct answer: Pest population density relative to crop value and control cost

The economic threshold is the pest density at which the cost of control equals the economic damage prevented, balancing crop value against control costs.

Question 96: Which soil order is characterized by an argillic or natric horizon and is commonly found in semi-arid grasslands?

Aridisols
Ultisols
Mollisols
Alfisols (Correct answer)

Correct answer: Alfisols

Alfisols have an argillic horizon with moderate-to-high base saturation and are typically found under temperate forests or semi-arid grasslands.

Question 97: A farmer applies 200 lbs/ac of 46-0-0 urea to a corn field one week before a heavy rainfall event. Which nitrogen loss pathway is the PRIMARY concern?

Volatilization of ammonia from soil surface before incorporation (Correct answer)
Denitrification of ammonium in saturated soils
Surface runoff of urea before hydrolysis can occur
Leaching of nitrate formed rapidly after hydrolysis and nitrification

Correct answer: Volatilization of ammonia from soil surface before incorporation

Surface-applied urea is highly susceptible to ammonia volatilization once hydrolyzed by urease, especially on high-pH or high-organic-matter soils if not incorporated by rainfall (>0.5 inch) or tillage.

Question 98: A grower wants to use a cover crop to suppress weeds and reduce soil erosion, but needs to terminate it effectively before planting a cash crop. Which termination method is generally considered least effective when used alone and often requires a follow-up action to prevent regrowth?

Tillage that incorporates the cover crop residue.
Mowing the cover crop. (Correct answer)
Application of a systemic herbicide like glyphosate.
Roller-crimping at the correct growth stage.

Correct answer: Mowing the cover crop.

While mowing can reduce the biomass of a cover crop, it is often ineffective as a sole termination method. Many cover crop species, especially grasses, will regrow from the crown after being mowed. For successful termination, mowing often needs to be followed by tillage or a herbicide application to prevent competition with the subsequent cash crop.

Question 99: Which of the following best describes the 'credit' given to legume nitrogen in a nutrient management plan when a non-legume crop follows in rotation?

A portion of legume-fixed N is credited based on legume stand quality and yield (Correct answer)
The full amount of N fixed by the legume is credited to the next crop
No nitrogen credit is given because fixed N is entirely consumed by the legume
Legume N credit is only applicable in organic production systems

Correct answer: A portion of legume-fixed N is credited based on legume stand quality and yield

Previous crop N credits are based on legume stand quality, yield, and decomposition rates, typically ranging from 40–200 lbs N/ac depending on crop type.

Question 100: Who should be involved in the implementation of an IPM program in a healthcare facility?

Only pest control professionals
Nursing staff only
Just the administration
All facility staff and pest control professionals (Correct answer)

Correct answer: All facility staff and pest control professionals

Successful IPM programs involve collaboration among healthcare staff, maintenance teams, and pest control professionals.

Question 101: A CCA is evaluating a field's potassium status where soil test K is 80 ppm (160 lbs/ac). For corn with a target yield of 200 bu/ac, this level is considered:

Low — K application will likely produce an economic yield response (Correct answer)
Sufficient — this level is at or above the critical threshold for corn
Excessive — no K application needed and luxury consumption is expected
Deficient — emergency foliar K application is recommended to avoid yield loss

Correct answer: Low — K application will likely produce an economic yield response

Most Midwest guidelines place the critical soil test K level for corn at 130–150 ppm; 80 ppm is below the critical level, predicting an economic response to K fertilization.

Question 102: A grower is selecting a fertilizer for an in-furrow (pop-up) application at planting. Which of the following common fertilizer sources has the highest salt index, posing the greatest risk of seedling injury if applied at excessive rates?

Potassium Chloride (KCl) (Correct answer)
Urea
Triple Superphosphate (TSP)
Monoammonium Phosphate (MAP)

Correct answer: Potassium Chloride (KCl)

The salt index measures a fertilizer's effect on the osmotic potential of the soil solution. A high salt index can cause 'fertilizer burn' by drawing moisture out of seedling roots. Potassium chloride (0-0-60), also known as muriate of potash, has one of the highest salt indices among common fertilizers (around 116) and must be used with extreme caution for in-furrow applications. By comparison, Urea is high (75), MAP is low (30), and TSP is very low (10).

Question 103: A farmer wants to apply anhydrous ammonia. Which soil condition most increases the risk of ammonia volatilization loss at application?

Dry, sandy soil with low organic matter (Correct answer)
Moist, cool soil with good tilth
Wet, heavy clay at field capacity
Frozen soil with crop residue cover

Correct answer: Dry, sandy soil with low organic matter

Dry, sandy soils do not seal the injection slot well and have low buffering capacity, allowing ammonia gas to escape rather than being retained in solution.

Question 104: To fulfill Koch's postulates and confirm that a microorganism causes a specific disease, which sequence of steps is required?

Isolate, identify, inoculate healthy host, reisolate and re-identify the same organism (Correct answer)
Observe, treat, and evaluate recovery
Culture on agar, spray on field, record results
Sequence DNA and compare to databases only

Correct answer: Isolate, identify, inoculate healthy host, reisolate and re-identify the same organism

Koch's postulates require isolating the putative pathogen, inoculating a healthy susceptible host to reproduce symptoms, then reisolating and confirming the same organism from the inoculated plant.

Question 105: What is the primary reason no-till systems tend to stratify nutrients near the soil surface?

No-till increases denitrification at the surface
Worm activity concentrates nutrients near the surface
No-till increases leaching of nutrients downward
Surface-applied nutrients are not incorporated by tillage (Correct answer)

Correct answer: Surface-applied nutrients are not incorporated by tillage

Without tillage to incorporate broadcast fertilizers and lime, nutrients accumulate at or near the soil surface rather than being mixed throughout the tillage layer.

Question 106: Which soil water potential term describes the component due to dissolved salts reducing water availability to plant roots?

Matric potential
Gravitational potential
Pressure potential
Osmotic (solute) potential (Correct answer)

Correct answer: Osmotic (solute) potential

Osmotic potential (also called solute potential) is the component of total water potential that decreases water availability due to dissolved salts in the soil solution.

Question 107: Which weed life cycle is generally the most difficult to control and eradicate from a field, primarily due to its ability to reproduce vegetatively from extensive underground structures?

Winter annuals
Biennials
Creeping perennials (Correct answer)
Summer annuals

Correct answer: Creeping perennials

Creeping perennials are the most difficult to control because they reproduce by both seed and vegetative structures like rhizomes, stolons, and tubers. Tillage can break up these structures and spread them, creating new plants. A single herbicide application may kill the top growth but often fails to translocate sufficiently to kill the entire extensive root and rhizome system, allowing the weed to regrow.

Question 108: A nutrient management plan incorporates the '4R' stewardship principles to optimize fertilizer use. What do the 4Rs stand for?

Right Source, Right Rate, Right Time, Right Place (Correct answer)
Rate, Runoff, Regulation, Record-keeping
Residue, Rotation, Rainfall, Replenishment
Reduce, Reuse, Recycle, Re-evaluate

Correct answer: Right Source, Right Rate, Right Time, Right Place

The 4R Nutrient Stewardship framework is a core concept in modern nutrient management. It stands for using the Right Source of nutrients, at the Right Rate, at the Right Time in the crop's life cycle, and in the Right Place for the crop to access them. Following these principles helps to maximize nutrient use efficiency, improve farm profitability, and minimize environmental impact.

Question 109: Frogeye leaf spot in soybeans is caused by which pathogen?

Septoria glycines
Cercospora sojina (Correct answer)
Phakopsora pachyrhizi
Colletotrichum truncatum

Correct answer: Cercospora sojina

Cercospora sojina causes frogeye leaf spot, producing circular lesions with pale gray centers and reddish-brown borders that resemble a frog's eye.

Question 110: Which growth stage is the most critical period for water stress in corn yield determination?

V6 (6-leaf)
VT/R1 (tasseling/silking) (Correct answer)
R3 (milk)
R5 (dent)

Correct answer: VT/R1 (tasseling/silking)

Water stress during VT/R1 (tasseling and silking) causes the greatest yield loss because pollination and kernel set are directly impaired.

Question 111: When calculating lime requirement using the SMP buffer pH method, a buffer pH of 6.2 for a target pH of 6.8 indicates:

Lime should be applied at a standard fixed rate regardless of buffer pH
No lime is needed because buffer pH exceeds 6.0
A small lime requirement because the soil is close to the target pH
A larger lime requirement than a buffer pH of 6.5 for the same target (Correct answer)

Correct answer: A larger lime requirement than a buffer pH of 6.5 for the same target

A lower SMP buffer pH indicates greater soil acidity and buffering capacity, requiring more lime to reach the target pH compared to a higher buffer pH reading.

Question 112: Crop rotation is the most effective long-term management strategy for which soybean pest?

Soybean rust
Sudden death syndrome
Soybean cyst nematode (SCN) (Correct answer)
White mold

Correct answer: Soybean cyst nematode (SCN)

Rotating to non-host crops like corn starves SCN populations because the nematode cannot complete its life cycle without soybean roots.

Question 113: A CCA is scouting a field and finds a pigweed species with smooth, hairless stems and petioles that are consistently longer than the leaf blades. Some leaves exhibit a faint, V-shaped watermark. Which of the following weeds has been identified?

Redroot pigweed (Amaranthus retroflexus)
Common lambsquarters (Chenopodium album)
Palmer amaranth (Amaranthus palmeri) (Correct answer)
Common waterhemp (Amaranthus tuberculatus)

Correct answer: Palmer amaranth (Amaranthus palmeri)

The key identifying characteristic for Palmer amaranth, which distinguishes it from similar species like waterhemp, is a petiole that is longer than the leaf blade itself. Both Palmer amaranth and waterhemp have smooth, hairless stems, whereas redroot pigweed has a hairy stem.

Question 114: The current ratio in farm financial analysis measures:

Long-term solvency relative to total assets
Annual return on equity invested in the farm
Short-term liquidity — the ability to pay near-term debts from current assets (Correct answer)
The efficiency of asset use in generating revenue

Correct answer: Short-term liquidity — the ability to pay near-term debts from current assets

The current ratio (current assets ÷ current liabilities) indicates whether a farm can meet its short-term financial obligations using assets that can be converted to cash within a year.

Question 115: Under the 4R nutrient stewardship framework, 'Right Source' refers to:

Matching the fertilizer form and grade to crop and soil needs (Correct answer)
Using only organic nutrient sources to minimize environmental impact
Selecting the source with the lowest cost per unit of nutrient
Applying nutrients from a certified supplier only

Correct answer: Matching the fertilizer form and grade to crop and soil needs

Right Source means selecting the correct fertilizer product—form, grade, and nutrient ratio—that matches crop requirements and soil conditions.

Question 116: To effectively manage pesticide resistance, a key IPM strategy is to rotate pesticides with different modes of action (MOA). Why is this practice recommended?

It ensures that all pesticides in a chemical family are used up before their expiration date.
It enhances the effectiveness of beneficial insects that may be present in the field.
It reduces the total amount of pesticide active ingredient applied to the field over a season.
It prevents the selection and buildup of resistant individuals within the pest population. (Correct answer)

Correct answer: It prevents the selection and buildup of resistant individuals within the pest population.

Repeatedly using pesticides with the same mode of action selects for the few individuals in a pest population that are naturally resistant. These individuals survive and reproduce, leading to a resistant population. By rotating to a different MOA, you target pests in a different way, making it less likely for resistance to a single mode of action to develop.

Question 117: A soil test reveals high phosphorus but low pH. Which condition most likely explains the reduced P availability?

P is volatilizing as phosphine gas
P is being fixed by Al and Fe oxides at low pH (Correct answer)
P is immobilized by soil bacteria
P is leaching below the root zone

Correct answer: P is being fixed by Al and Fe oxides at low pH

At low pH, aluminum and iron oxides become highly reactive and fix phosphorus into insoluble compounds, reducing plant availability.

Question 118: Which micronutrient deficiency is most commonly associated with high-pH calcareous soils and appears as interveinal chlorosis on young leaves?

Iron (Correct answer)
Copper
Boron
Manganese

Correct answer: Iron

Iron deficiency chlorosis is common in calcareous soils (pH > 7.5) because Fe³⁺ precipitates as insoluble hydroxides, and young leaves show interveinal yellowing first.

Question 119: Evapotranspiration (ET) as used in irrigation scheduling represents:

The combined water loss from soil evaporation and plant transpiration (Correct answer)
Only the water lost through plant leaf transpiration
The rate at which water infiltrates the soil profile
The amount of rainfall minus runoff

Correct answer: The combined water loss from soil evaporation and plant transpiration

ET combines water evaporated from the soil surface and water transpired by plants, and is the primary measure used to estimate crop water demand for scheduling irrigations.

Question 120: In the context of precision agriculture, which soil variable is most commonly mapped using electrical conductivity (EC) sensors?

Soil organic carbon
Microbial biomass
Soil texture and water-holding capacity (Correct answer)
Nitrate concentration

Correct answer: Soil texture and water-holding capacity

Apparent soil electrical conductivity (ECa) is strongly correlated with soil texture, clay content, and water-holding capacity, making it the primary variable mapped with EC sensors.

Question 121: What does the leaf area index (LAI) represent in crop physiology?

Ratio of leaf length to leaf width
Number of leaves per plant
Total leaf surface area per unit ground area (Correct answer)
Total root surface area per unit soil area

Correct answer: Total leaf surface area per unit ground area

LAI is the ratio of total one-sided leaf area to the ground surface area beneath the crop canopy, reflecting light interception capacity.

Question 122: Wheat streak mosaic virus is primarily transmitted by which vector?

Thrips
Aphids
Leafhoppers
Wheat curl mites (Correct answer)

Correct answer: Wheat curl mites

The wheat curl mite (Aceria tosichella) is the primary arthropod vector responsible for transmitting wheat streak mosaic virus.

Question 123: What is the best strategy to reduce nitrogen volatilization?

Incorporating fertilizer or using urease inhibitors (Correct answer)
Applying ammonium nitrate only
Broadcasting urea on dry soil
Irrigating immediately with overhead sprinklers

Correct answer: Incorporating fertilizer or using urease inhibitors

Incorporating urea into the soil or applying urease inhibitors can significantly reduce nitrogen loss through volatilization.

Question 124: The release of mass-reared lady beetles to control an aphid population in a greenhouse is an example of which type of biological control?

Augmentative (Correct answer)
Competitive
Classical
Conservation

Correct answer: Augmentative

Augmentative biological control involves the periodic release of natural enemies, like lady beetles, to supplement the existing population and suppress a pest. Classical biological control is the introduction of a non-native natural enemy to control an invasive pest, with the goal of permanent establishment. Conservation biological control focuses on practices that protect and enhance existing populations of natural enemies.

Question 125: A nutrient management plan for an organic grain operation must account for manure and compost applications. Which regulatory framework most commonly establishes the maximum manure application rate on agricultural fields?

FDA Food Safety Modernization Act water quality provisions
State nutrient management regulations based on crop N or P removal, whichever is most restrictive (Correct answer)
USDA NOP regulations requiring P-based application on all certified organic fields
EPA Clean Water Act Section 402 NPDES permit requirements for all farms

Correct answer: State nutrient management regulations based on crop N or P removal, whichever is most restrictive

Most state nutrient management regulations require planning based on crop nitrogen needs or soil phosphorus levels, applying whichever results in the lower (more protective) application rate.

Question 126: Distribution uniformity (DU) of an irrigation system is measured primarily by:

Collecting catch-can measurements across the irrigated area and comparing the low-quarter average to the mean application depth (Correct answer)
Calculating the ratio of maximum to minimum application depths across a field
Counting the number of sprinkler heads operating simultaneously
Measuring the pumping pressure at the mainline supply point

Correct answer: Collecting catch-can measurements across the irrigated area and comparing the low-quarter average to the mean application depth

DU uses catch-can or flow-meter data to compare the average of the lowest 25% of application amounts to the overall mean, with higher DU values (closer to 1.0) indicating more uniform water coverage.

Question 127: A farmer incorporates a large amount of mature cereal rye cover crop residue, which has a high carbon-to-nitrogen (C:N) ratio, into the soil shortly before planting corn. What is the most likely immediate effect on nitrogen availability for the corn crop?

A rapid increase in available nitrogen due to fast mineralization of the residue.
No significant change in nitrogen availability, as the corn crop cannot use organic N.
An immediate increase in atmospheric nitrogen fixation by free-living bacteria.
A temporary decrease in available soil nitrogen due to microbial immobilization. (Correct answer)

Correct answer: A temporary decrease in available soil nitrogen due to microbial immobilization.

Residues with a high C:N ratio (typically >25:1 or 30:1) do not contain enough nitrogen to meet the needs of the soil microbes that decompose them. The microbes will take up available inorganic nitrogen (nitrate and ammonium) from the soil to break down the carbon-rich residue. This process, called immobilization, temporarily 'ties up' soil nitrogen, making it unavailable to the cash crop until the microbes die and the nitrogen is re-released (mineralized).

Question 128: A farm balance sheet provides which type of financial information?

A schedule of loan principal payments
Annual profit and loss for the farm business
Monthly cash receipts and disbursements
Assets owned, liabilities owed, and net worth at a point in time (Correct answer)

Correct answer: Assets owned, liabilities owed, and net worth at a point in time

A balance sheet is a financial snapshot listing what the farm owns (assets), what it owes (liabilities), and the difference (net worth or equity) at a specific date.

Question 129: Which soil physical measurement is most directly used to predict how much irrigation water a field can hold between field capacity and permanent wilting point?

Soil texture alone
Bulk density
Plant-available water capacity (AWC) (Correct answer)
Saturated hydraulic conductivity

Correct answer: Plant-available water capacity (AWC)

Plant-available water capacity (AWC) is the difference in volumetric water content between field capacity and permanent wilting point, directly expressing water storage for irrigation scheduling.

Question 130: Which of the following is a key component of an effective IPM program in correctional facilities?

Regular pest monitoring (Correct answer)
Using pesticides weekly
Providing more food waste
Sealing off ventilation

Correct answer: Regular pest monitoring

Regular monitoring helps identify pest issues early and evaluate the effectiveness of pest management strategies.

Question 131: What is the primary purpose of a cover crop termination window before cash crop planting?

Allow residue decomposition and reduce allelopathy risk (Correct answer)
Eliminate beneficial insects before planting
Maximize cover crop seed production
Increase soil compaction for better seed contact

Correct answer: Allow residue decomposition and reduce allelopathy risk

Terminating cover crops 2–4 weeks before planting allows residue to begin decomposing and reduces allelopathic compounds that can inhibit cash crop germination.

Question 132: Which seeding depth is generally recommended for small-seeded crops like alfalfa?

3.5 to 4.0 inches
2.5 to 3.0 inches
1.5 to 2.0 inches
0.5 to 1.0 inch (Correct answer)

Correct answer: 0.5 to 1.0 inch

Small-seeded crops like alfalfa have limited seed energy reserves and should be planted at 0.5–1.0 inch to ensure rapid emergence.

Question 133: Which maturity group of soybeans would be most appropriate for production in the northern Corn Belt (Minnesota/Wisconsin)?

Maturity groups VI–VII
Maturity groups IV–V
Maturity groups 00–I (Correct answer)
Maturity groups VIII–X

Correct answer: Maturity groups 00–I

Maturity groups 00–I are adapted to short growing seasons in the northern Corn Belt where early fall frosts limit the season.

Question 134: What is the primary agronomic advantage of using a chelated form of a micronutrient, such as zinc EDTA, compared to an inorganic salt form, like zinc sulfate, particularly in high pH or high phosphorus soils?

Chelated forms provide a much slower, season-long release of the nutrient.
The chelate protects the nutrient ion from being tied up by adverse soil reactions, keeping it available for plant uptake. (Correct answer)
The chelate lowers the soil pH in the application zone, increasing general nutrient availability.
Chelated forms are significantly less expensive per pound of actual nutrient.

Correct answer: The chelate protects the nutrient ion from being tied up by adverse soil reactions, keeping it available for plant uptake.

A chelate is a large organic molecule that surrounds and chemically bonds to a metallic micronutrient ion (like Zn++, Fe++, Mn++). This protective 'claw' prevents the positively charged nutrient from reacting with negatively charged soil components (like hydroxide or phosphate ions), which are abundant in high pH or high P soils and would otherwise cause the micronutrient to precipitate and become unavailable. This protection keeps the nutrient soluble and available for plant root uptake.

Question 135: Which carbon-to-nitrogen (C:N) ratio range promotes net nitrogen mineralization rather than immobilization by soil microbes?

C:N 20:1–30:1
C:N > 30:1
C:N > 50:1
C:N < 20:1 (Correct answer)

Correct answer: C:N < 20:1

When the C:N ratio of residue falls below about 20:1, microbes have excess nitrogen relative to carbon needs, releasing mineral N through net mineralization.

Question 136: Which type of soil water is held so tightly by soil particles that it is unavailable to plants?

Field capacity water
Hygroscopic water (Correct answer)
Capillary water
Gravitational water

Correct answer: Hygroscopic water

Hygroscopic water is bound tightly to soil particles at matric potentials below −3,100 kPa and cannot be extracted by plant roots.

Question 137: What is the primary benefit of conservation tillage in soil management?

Reduces soil erosion (Correct answer)
Increases water runoff
Reduces pesticide use
Improves seed germination rate

Correct answer: Reduces soil erosion

Conservation tillage helps reduce soil erosion by maintaining crop residue on the soil surface, which protects the soil from wind and water erosion.

Question 138: Which aggregate stability test is most commonly used to evaluate a soil's susceptibility to surface sealing and crusting?

Wet sieve analysis
Atterberg limit test
Slake test (Correct answer)
Penetrometer reading

Correct answer: Slake test

The slake test measures how quickly aggregates break apart when submerged in water, indicating susceptibility to surface sealing and crusting.

Question 139: A soybean field is subjected to a period of severe drought and heat stress. At which of the following reproductive growth stages would this stress cause the most significant yield loss, primarily through flower and pod abortion?

R1 (Beginning Bloom)
R3 (Beginning Pod) to R5 (Beginning Seed) (Correct answer)
VE (Emergence)
R7 (Beginning Maturity)

Correct answer: R3 (Beginning Pod) to R5 (Beginning Seed)

The period from R3 (Beginning Pod) through R5 (Beginning Seed) is the most critical for soybean yield determination. Stress during this window directly impacts the number of pods per plant and seeds per pod, which are the primary yield components. The plant has a decreasing ability to compensate for lost pods and flowers as it moves through these stages.

Question 140: A producer is experiencing concentrated flow erosion forming small, defined channels across a sloping field after heavy rainfall. These channels are shallow enough to be removed by normal tillage operations. What is the most accurate term for this type of water erosion?

Gully erosion
Splash erosion
Sheet erosion
Rill erosion (Correct answer)

Correct answer: Rill erosion

Rill erosion is characterized by the formation of small, well-defined channels caused by concentrating runoff. A key feature is that these channels, or rills, are small enough to be smoothed over by standard tillage equipment. Sheet erosion is the more uniform removal of soil in a thin layer, gully erosion involves larger channels too deep to be crossed by farm machinery, and splash erosion is the initial detachment of soil particles by raindrop impact.

Question 141: Soil texture most directly affects irrigation scheduling because it determines:

Soil water-holding capacity and infiltration rate (Correct answer)
The evaporative demand of the atmosphere
The crop's genetic water use efficiency
The oxygen demand of soil microorganisms

Correct answer: Soil water-holding capacity and infiltration rate

Soil texture controls pore size distribution, which dictates how much plant-available water a soil can hold (field capacity minus wilting point) and how rapidly water moves through the profile.

Question 142: A CCA is developing a nutrient management plan for a field with a CEC of 8 meq/100g. Which micronutrient deficiency is MOST likely to occur in this sandy, low-CEC soil?

Manganese
Zinc (Correct answer)
Boron
Molybdenum

Correct answer: Zinc

Zinc deficiency is most common in coarse-textured, low-organic-matter soils with low CEC, especially in the upper Midwest and Pacific Northwest.

Question 143: Which of the following represents the CORRECT order of cation adsorption strength on a negatively charged clay surface (weakest to strongest)?

Na+ < K+ < Mg2+ < Ca2+ < Al3+ (Correct answer)
Ca2+ < Mg2+ < K+ < Na+ < Al3+
Al3+ < Ca2+ < Mg2+ < K+ < Na+
K+ < Ca2+ < Mg2+ < Al3+

Correct answer: Na+ < K+ < Mg2+ < Ca2+ < Al3+

Adsorption strength increases with charge and decreases with ionic radius; Al3+ > Ca2+ > Mg2+ > K+ > Na+ is the lyotropic series for common soil cations.

Question 144: Which of the following best describes the purpose of a pressure regulator installed on center-pivot or drip irrigation systems?

To maintain consistent operating pressure at each emitter or nozzle regardless of elevation or line pressure variation (Correct answer)
To filter sediment and bacteria from the irrigation water supply
To increase water pressure to overcome elevation differences across a field
To measure the total flow volume delivered to the field

Correct answer: To maintain consistent operating pressure at each emitter or nozzle regardless of elevation or line pressure variation

Pressure regulators maintain a consistent, designed operating pressure at each emitter or sprinkler head, preventing over- or under-application caused by pressure variations along the lateral or from inlet pressure fluctuations.

Question 145: Which of the following best defines the Economic Threshold (ET) in an Integrated Pest Management (IPM) program?

The point at which pest damage is visible in the field, justifying the cost of scouting.
The pest density at which control measures should be applied to prevent the pest population from reaching the Economic Injury Level. (Correct answer)
The lowest pest population density that will cause economic damage.
The maximum pest population that can be tolerated without any yield loss.

Correct answer: The pest density at which control measures should be applied to prevent the pest population from reaching the Economic Injury Level.

The Economic Threshold (ET), also known as the Action Threshold, is the point at which a pest population is projected to reach the Economic Injury Level (EIL) if no management action is taken. Therefore, it is the trigger point for implementing control measures to prevent economic loss.

Question 146: A soil has a bulk density of 1.35 g/cm³ and a particle density of 2.65 g/cm³. What is its total porosity?

49% (Correct answer)
51%
35%
65%

Correct answer: 49%

Total porosity = (1 - bulk density/particle density) × 100 = (1 - 1.35/2.65) × 100 ≈ 49%.

Question 147: A cash rent lease arrangement means the tenant pays the landowner:

Grain in lieu of cash payment
A fixed dollar-per-acre amount regardless of yield or price (Correct answer)
An amount determined after harvest based on actual costs
A percentage of the harvested crop value each year

Correct answer: A fixed dollar-per-acre amount regardless of yield or price

Cash rent is a predetermined fixed dollar-per-acre annual payment to the landowner that does not vary with commodity prices or crop yields.

Question 148: What is the safest approach to pest control in patient areas?

Installing more lighting
Allowing pests to coexist
Use of non-chemical methods (Correct answer)
Routine chemical spraying

Correct answer: Use of non-chemical methods

Non-chemical controls, such as traps or sanitation improvements, reduce exposure risks for patients and staff.

Question 149: Which soil amendment is most appropriate for reclaiming a high-pH sodic soil when free calcium carbonate (lime) is already present?

Calcium chloride (CaCl₂)
Agricultural lime (CaCO₃)
Elemental sulfur (S) (Correct answer)
Gypsum (CaSO₄·2H₂O)

Correct answer: Elemental sulfur (S)

Elemental sulfur is oxidized to sulfuric acid by soil bacteria, which dissolves native lime and releases calcium to displace sodium without adding excess calcium that lime already provides.

Question 150: Which soil texture typically has the highest water-holding capacity?

Sandy
Clay (Correct answer)
Silt
Loamy

Correct answer: Clay

Clay soils have a high water-holding capacity due to their small particle size and high surface area, which allows them to retain more moisture.

CCA Certified Crop Adviser Exam

The International Certified Crop Adviser (CCA) exam assesses agronomic knowledge across nutrient management, soil and water management, pest management, and crop management to certify professionals who advise on crop production practices.

150

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150 min

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