Sustainable agriculture involves

1. mixed farming
2. mixed cropping
3. crop rotation
4. all of these

Correct Answer: (d) all of these

Explanation:

Mixed cropping is a method of growing more than one kind of crop in the same field, having the same growing season. This will help in utilizing the maximum amount of land and producing more kinds of crops in a small duration.

Monocropping will damage soil fertility as cultivating the same type of crop repeatedly in the soil absorbs a particular type of nutrient completely from the soil. It creates a nutrient deficiency in the soil.

 Crop rotation is a technique of growing different crops on the same field in a pre-planned succession. Soil loses its fertility if the same crops are grown repeatedly. Hence, it is necessary to do crop rotation. Crop rotation can either be a one, two, or three-year rotation.