Agriculture notes prepared by IAS Topper for all agriculture based competitive exams-Agronomy-Crop Rotation

Crop rotation

“Growing different crops in succession on same piece of land over a period of time with an objective of maximize the profit without impairing the soil fertility”. It also includes orderly succession of crops repeated for many times including crop fallow.

Principles

• Crop with tap roots should be rotated with crops having fibrous roots to tap the available nutrients in the soil
• Legumes should be followed by non-legumes to utilize fixed nitrogen content
• Exhaustive crop to be rotated with non-exhaustive crop
• Crops of same family should not be repeated to prevent pest, disease and weed build up in the same piece of land
• Erosion permitting crop should be followed by erosion preventing crop (legumes) in sloppy areas
• Selection of crops should be need based and demand based. Ex. Drought tolerant crops to be rotated in dry land areas, logging resistant crops in waterlogged soils.

Examples for crop rotation

Paddy-Wheat (one year rotation)

Maize-Wheat (one year rotation)

Maize-Potato (one year rotation)

Maize-Potato-Sugarcane (2 year rotation)

Paddy-Sugarcane-Wheat (2 year rotation)

Problems with the high yielding variety cultivation

a). Crop Diversification: Since high yielding varieties were only developed in grain crops, diverse cultivation of pulses, oil seeds and fodder crops were not taken up, thereby resulting in a blow to crop diversification. This resulted in over flow in the grain crops and scarcity in other crop produces.

b). Agronomic problems: Monoculturing of grain crops in large areas resulted in many complicated problems

• Decline in soil fertility and many of the micro nutrients were depleted from the soil horizon
• Due to heavy use of fertilizers, water and soil were contaminated resulting in change in soil character and threat to soil fauna and flora.
• Outbreak of pest and diseases, weed infestation and other pest attacks due to conducive environment. Indiscriminate use of pesticide resulted in pollution, pest resistance and flare up.
• Improper water management resulted in the increase of salinity of soil and water logging problems.

c). Economic and social problems

• The fruit of high yielding varieties were restricted to only few regions of the country resulting in patchy development. Very few sections of the society benefited out of it and it did not benefit small and medium farmers.