Amendments and Practices

Sustainable farming embraces a number of practices and techniques to build fertile soil and healthy crops. Here is an overview of traditional as well as emerging methods that are commonly used:

Crop Rotation - Growing the same crop repeatedly in the same place eventually depletes the soil of various nutrients. One way that farmers can avoid a decrease in soil fertility is to practice crop rotation, by which different crops are planted in a regular sequence so that a crop that leaches the soil of one kind of nutrient is followed during the next growing season by a crop that returns that nutrient to the soil. If crop rotation is done properly, farmers can keep their fields under continuous production, without a need to let them lie fallow or to apply artificial fertilizers. Crop rotation is also used to control pests and diseases that establish in the soil. Families of plants tend to have similar pests. By regularly changing the planting location, the pest cycles can be broken or limited.

For more information on crop rotations, visit our source: http://attra.ncat.org/attra-pub/organiccrop/tools2.html

Green Manures & Cover Cropping - "Green manuring" involves the soil incorporation of any field or forage crop while green or soon after flowering, for the purpose of soil improvement. A cover crop is any crop grown to provide soil cover, regardless of whether it is later incorporated. Cover crops are grown primarily to prevent soil erosion by wind and water. Cover crops and green manures can be annual, biennial, or perennial herbaceous plants grown in a pure or mixed stand during all or part of the year. In addition to providing ground cover and, in the case of a legume, fixing nitrogen, they also help suppress weeds and reduce insect pests and diseases. When cover crops are planted to reduce nutrient leaching following a main crop, they are often termed "catch crops."

For more information on green manures & cover cropping, visit http://www.attra.org/attra-pub/covercrop.html

Conservation Tillage - In conservation tillage, crops are grown with minimal cultivation of the soil. When the amount of tillage is reduced, the stubble or plant residues are not completely incorporated, and most or all remain on top of the soil rather than being plowed or disk ed into the soil. The new crop is planted into this stubble or small strips of tilled soil. The principal benefits of conservation tillage are improved water conservation and reduction of soil erosion. Additional benefits include reduced fuel consumption, reduced compaction, planting and harvesting flexibility, reduced labor requirements and improved soil tilth.

For more information on conservation tillage, visit our source:
http://www.attra.org/attra-pub/organicmatters/conservationtillage.html
http://www.attra.org/attra-pub/PDF/consertill.pdf (pdf file)

Manures & Composting - Livestock manures are the most traditional and widely recognized organic fertilizers. Under ideal circumstances, livestock enterprises are integrated into the whole farm operation, and manuring becomes part of a closed system of nutrient recycling. This is still strongly encouraged in organic operations. In reality, however, crops and livestock production are often divorced from each other and manures must be imported.

This has created some concerns in the organic community, as much manure is now generated by large, industrial agriculture feeding . Another issue that has grown up around manure use in organic farming relates to food safety. At a time when concerns about microbial contamination are high, questions have been raised about the risks associated with manure use on food crops. Certified organic producers have strict guidelines to follow in handling and applying manures. Most certifiers require from 90 to 120 days between the application of non-composted manures and the harvest of a food crop.

One of the most heartily recommended means of handling manures is composting to encourage the decomposition of organic matter. Composting stabilizes the nutrients in manure, builds populations of beneficial organisms, and has a highly beneficial effect on soils and crops. Compost can be produced on-farm or imported from other sources and includes such materials as landscape trimmings, crop residues, paper pulp, food scrap, wood chips, manure and bio-solids. Additional products from composts, such as compost teas or worm castings, have special applications in organic agriculture.

For more information on manures and composting, visit http://attra.ncat.org/attra-pub/organiccrop/tools3.html

Intercropping & Companion Planting – Interplanting two or more mutually beneficial crops in close proximity is one strategy for increasing biodiversity. In large-scale mechanized crop culture, this is called intercropping. It typically involves alternating rows or a number of rows of compatible field crops, like soybeans and corn. It also applies to sowing of forage crops, like alfalfa, bromegrass, and timothy, when these are grown together.

When interplanting is done on a smaller scale, it is often called companion planting. A classic example of companion planting is the interplanting of corn with pole beans and vining squash or pumpkins. In this system, the beans provide nitrogen; the corn provides support for the beans and a “screen” against squash vine borer; the vining squash provides a weed suppressive canopy and discourages corn-hungry raccoons.

For more information on intercropping & companion planting, visit
http://www.attra.org/attra-pub/intercrop.html
http://www.attra.org/attra-pub/complant.html

Mulching - Mulching is a practice often used by organic growers. Traditionally, it entails the spreading of large amounts of organic materials—straw, old hay, wood chips, etc.—over otherwise bare soil between and among crop plants. Organic mulches regulate soil moisture and temperature, suppress weeds, and provide organic matter to the soil. Mulching is most appropriate to small, intensive operations with high-value annual or fruit crops.