Inadequate crop rotation

Without adequate crop rotation, soils become depleted, and lower crop yields result. This is particularly true if the crop is cultivated frequently and returns little crop residue to the soil. Weeds, diseases and insects also become more of a problem, and the farmer who intends to grow one crop year after year becomes completely dependent on disease-resistant varieties of plants, chemical insecticides and fungicides, soil fumigation, and other methods of controlling diseases, insects and pests.