Agriculture and Environment Water Resources & Irrigation Management 2 — Questions and Answers
Question 1: Which practice most effectively reduces agricultural irrigation water loss from evaporation?
- Irrigating during midday when temperatures are highest
- Using overhead sprinklers in windy conditions
- Irrigating at night or early morning (Correct answer)
- Increasing irrigation frequency throughout the day
Correct answer: Irrigating at night or early morning
Irrigating at night or early morning reduces evaporation losses because temperatures and wind speeds are lower, allowing more applied water to reach plant roots rather than being lost to the atmosphere.
Question 2: A farm 'water budget' primarily tracks:
- The financial cost of purchasing water rights and pump electricity
- Water inputs, outputs, and storage to ensure sustainable use (Correct answer)
- The number of water rights and permits owned by an operation
- Monthly precipitation totals from weather station records
Correct answer: Water inputs, outputs, and storage to ensure sustainable use
A farm water budget accounts for all inputs (precipitation, irrigation) and outputs (ET, runoff, deep percolation) to manage water resources sustainably across the growing season.
Question 3: What is deficit irrigation as a water management strategy?
- Applying less water than full crop requirements during drought-tolerant growth stages to conserve water (Correct answer)
- A situation where a farm has insufficient water rights to meet crop needs
- Irrigation that exclusively uses recycled or reclaimed wastewater
- Over-irrigating during early season to build soil water reserves
Correct answer: Applying less water than full crop requirements during drought-tolerant growth stages to conserve water
Deficit irrigation intentionally applies less water than full crop requirements during growth stages when crops are most drought-tolerant, conserving water with minimal impact on final yield.
Question 4: Which cover crop practice best improves soil water retention in dryland farming systems?
- Tilling deeply before planting to break up hardpan layers
- Selecting deep-rooted cover crops that improve soil structure and organic matter (Correct answer)
- Applying synthetic fertilizers before cover crop establishment
- Burning cover crop residue to release nutrients before the next season
Correct answer: Selecting deep-rooted cover crops that improve soil structure and organic matter
Deep-rooted cover crops improve soil structure by creating biopores and increasing organic matter content, which significantly enhances the soil's water-holding capacity and infiltration rate.
Question 5: In irrigation management, what does the 'uniformity coefficient' measure?
- How evenly water is distributed across an irrigated field (Correct answer)
- The chemical uniformity of irrigation water quality across a season
- The consistency of soil texture and type in irrigated fields
- The uniformity of crop yields across different zones of a field
Correct answer: How evenly water is distributed across an irrigated field
The uniformity coefficient (Christiansen's CU) measures how evenly water is distributed across an irrigated field; higher values indicate more uniform distribution and better system performance.
Question 6: What is the primary purpose of surge irrigation in furrow irrigation systems?
- To rapidly flood fields during drought emergencies for maximum infiltration
- To improve water distribution uniformity by delivering water in intermittent pulses (Correct answer)
- To increase downstream water pressure in drip irrigation systems
- To flush accumulated salts from soil through high-volume water application
Correct answer: To improve water distribution uniformity by delivering water in intermittent pulses
Surge irrigation delivers water in timed pulses to furrows, which improves advance rate uniformity and distribution efficiency compared to continuous-flow furrow irrigation.
Question 7: Which irrigation management practice can lead to soil salinization over time if not properly addressed?
- Drip irrigation with fresh, low-salinity water sources
- Rainwater harvesting for supplemental crop irrigation
- Continuous irrigation without adequate leaching fractions (Correct answer)
- Subsurface tile drainage to remove excess soil moisture
Correct answer: Continuous irrigation without adequate leaching fractions
Continuous irrigation without adequate leaching (applying extra water to flush salts below the root zone) causes progressive salt accumulation in soils, reducing crop productivity and soil health.
Agriculture and Environment Water Resources & Irrigation Management 2
Which practice most effectively reduces agricultural irrigation water loss from evaporation?