UPSC Civil Services 2020 Prelims General Studies Paper I

All the given options are correct as they are beneficial for increasing the agricultural productivity and ecological sustainability of agriculture in India.

Option 1 is correct. Major advantages of crop diversification include income increases of small farm holdings; less risk for price fluctuation, climatic variability etc.; balancing food demand etc

Option 2 is also correct. Legumes fix the atmospheric nitrogen, release in the soil high-quality organic matter and facilitate soil nutrients' circulation and water retention

Option 3 is also correct with regard to India. Tensiometers are used in irrigation scheduling to help farmers and other irrigation managers to determine when to water.

Option 4 is also correct. With limited land availability in India Vertical farming is the practice of growing produce in vertically stacked layers.