Agronomy Cheat Sheet 2026

The 30 highest-yield Agronomy facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What role do mycorrhizal fungi play in plant nutrition? → Extend root surface area for nutrient uptake
2. Which of the following crops may be grown without irrigation? → Millets
3. What is the field capacity of a soil? → The soil water content after free drainage has ceased following saturation
4. What does 'mode of action' refer to for a herbicide? → The biochemical pathway or enzyme in the plant the herbicide disrupts
5. Open-pollinated varieties differ from hybrid varieties primarily because they do what? → Breed true from saved seed and maintain genetic consistency
6. Which of the following crops can withstand draught better? → Cowpea
7. What is the microbial process that converts organic nitrogen in soil organic matter into plant-available ammonium (NH4+)? → Ammonification
8. Which of the following is a common method for measuring soil moisture in irrigated fields? → Tensiometer
9. Soil salinity is measured using which instrument or method? → Electrical conductivity meter
10. Which soil order is commonly found in the Corn Belt and is highly productive for agriculture? → Mollisol
11. Which cultural practice is most effective at slowing the development of herbicide-resistant weed populations? → Rotating herbicide modes of action and integrating non-chemical weed control
12. Which USDA zone of crop pest reporting helps agronomists track insect migration patterns? → Cooperative Agricultural Pest Survey (CAPS)
13. What is an 'economic threshold' in pest management? → The pest density at which control action must be taken to prevent economic loss
14. Which environmental factor does NOT directly drive stomatal opening or closing? → Soil pH
15. In sprinkler irrigation design, what does 'distribution uniformity' measure? → How evenly water is applied across the irrigated area
16. What is the primary advantage of using certified seed over saved farm seed? → Guaranteed genetic purity, germination rate, and freedom from weed seeds
17. What does the term 'quantitative trait' mean in plant genetics? → A trait controlled by many genes showing continuous variation
18. What is the main purpose of a grassed waterway in a crop field? → Safely convey concentrated surface runoff without causing erosion
19. What is the net ATP yield per glucose molecule during complete aerobic cellular respiration? → 36–38 ATP
20. Potassium deficiency in crops typically first appears as what symptom? → Marginal leaf scorch on older leaves
21. Polyploidy in plants refers to what condition? → Having more than two complete sets of chromosomes
22. Liming a soil primarily corrects which soil problem? → Excessive acidity
23. Which of the following crops produces non-edible oil cakes? → Linseed
24. Which soil health indicator is most directly improved by increasing crop diversity in a rotation? → Soil biological diversity and microbial biomass
25. Which breeding method is most commonly used to develop new inbred lines for hybrid corn production? → Selfing (self-pollination) for multiple generations
26. What is the Leaf Area Index (LAI)? → The ratio of total one-sided leaf area to ground surface area
27. Which of the following is grown during the kharif season and is India's second-most significant pulse crop? → Arhar
28. Which inheritance pattern involves two genes that independently affect the same trait? → Epistasis
29. What of the following crops are seedlings used to sow? → Paddy
30. Which practice helps reduce lodging in small grain crops such as wheat? → Applying plant growth regulators