One of the strongest arguments in favor of organic farming is that it does not pose the threat of pesticide and chemical run-off and the resulting contamination of watersheds and drinking water. Organic farming creates a richer, more sustainable soil through the use of cover crops, diverse crop rotations and organic composts. Cover crops also can attract beneficial insects that help control pests. Instead of growing the same crop in the same field year after year, organic farmers use crop rotation, which means they vary the types of crops that are grown in any particular field each year.
Crop rotation helps to deter pests from returning regularly.
It can be beneficial in slowing soil erosion, and it also varies the nutrient demands placed on the soil. If these non-chemical methods of pest control fail, the state's organic certification agency will have the option to grant permission for the grower to apply botanical pesticides under restricted conditions. Composted manure is also used to keep soil rich in nutrients. In addition, compost helps the soil retain moisture, thereby protecting plants in times of drought and reducing their need for irrigation. Some critics have contended, however, that the manure used in organic compost may be more harmful than the health risks from pesticide residues.