Tools & Practices (continued)

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.

Biological Pest Control

Organic farming relies heavily on populations of beneficial insect predators and parasites, pest disease agents, insect-eating birds and bats, and other creatures, to help manage pest problems. These biological control agents help keep pest numbers at reasonable levels where further cultural activities or relatively mild pesticides are (usually) adequate to assure an economic crop yield. In some instances, biological control can be so effective that no additional action is even needed by the farmer.

Biological control is often considered a default benefit of the soil fertility practices of organic farming. The diversity of crops in a soil building rotation, the use of cover crops, and other practices build a diverse soil biology which works to keep soil pests in check. They also provide substantial above-ground habitat for beneficials. The absence of pesticides also favors biocontrol.

In many organic systems, farmers undertake additional steps to support biological control. This sometimes involves the purchase and release of control agents like ladybird beetles, lacewings, trichogramma wasps, etc., or the use of weeder geese—a rather unique but effective kind of biological weed control.

Increasingly, growers are designing and maintaining both permanent and temporary habitats specifically for beneficial insects, spiders and other helpful species. This has come to be known as farmscaping.

Sanitation

Sanitation can take on many forms, such as:

• removal, burning, or deep plowing of crop residues that could carry plant disease or insect pest agents
• destruction of nearby weedy habitats that shelter pests
• cleaning accumulated weed seeds from farm equipment before entering a new, “clean” field
• sterilizing pruning tools

As in human and animal health, sanitation practices can go a long way in preventing crop pest problems. However, many practices—such as clean cultivation, deep plowing, and the burning of crop residues—can increase erosion and reduce biodiversity. Thus, they may conflict with long-term goals of sustainability. Good organic growers recognize this and treat those practices as transitional or rescue options, rather than relying on them on an annual basis.