Growing crops in the same place year after year exhaust soil nutrients and exacerbates pest problems. To overcome these, farmers use cover crops.

Cover crops are annual, biennial or perennial plants grown as monoculture or polyculture during all or part of the year. The main roles of cover crops are to:

- improve soil condition
- conserve water
- suppress weeds
- control erosion
- control insect pests

Cover crops are not intended to be harvested for feed or sale.

There are various types of cover crops:

Type Planting timing Functions Crops
Winter Cover Crop Late summer or fall To cover soil during winter Mainly legume, which has excellent nitrogen fixation ability and cold tolerability
Summer Green Manure Crop During summer To increase biomass, improve soil fertility preparing for perennial season. Both legume and non-legume crops
Living Mulch In between seasons of annual crops or seasons of perennial crops To improve soil fertility, increase water filtration, control erosion and suppress weeds Legume or non-legume, including vegetables
Catch Crop After harvesting of cash crop To prevent soil nutrient leaching Legume or non-legume
Forage Crop In between seasons To improve soil quality Legume or grass-legume

The choice of cover crops used is dependent on the problems faced and specific needs of farmers.