For example, in sugar beet production the main reason for crop rotation are:
*To increase active organic matter in the soil
*To make more efficient use of available plant nutrients in the soil
*To aid in control of harmful weeds, insects and nematodes
Crop rotation help prevent the buildup of weeds adapted to particular cropping system. Certain weeds are more common in some crops than others.
Pigweed, lambs squatter, common ragweed, velvetleaf, cocklebur, foxtail species and crabgrass are found in summer –cultivated crops such as corn.
A good rotation will decrease soil-borne disease and pest outbreaks. These two pressures on the organic farm are often the primary motivation for growers to create a rotation, as the damage of one outbreak can decimate several cash crops in just a few days.
Another reason is to build up and maintain soil fertility. Each crop differs in the amounts of nutrients it needs from the soil and in what it gives back to the soil.
Crop rotation historically was very important for managing weed problems. Today, rotation is used more for managing disease and insects than weeds.
Reason for crop rotation