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California Certified Organic Farmers Organic Farming Basics

Organic farmers realize that the soil is a living entity and that organic practices feed the soil which in turn feed the plant. Organic farming is a management intensive, not a materials intensive, technology; materials are a supplementary tool in a balanced farm management program. Organic farmers attempt to understand and work in harmony with the natural biological systems on the farm, not to override them with chemicals (even naturally derived ones). They strive to develop cultural and biological means of crop nutrition and protection that are balanced, sustainable, and resilient.

Basic Concepts

The following are some of the concepts and practices that are fundamental to organic production and should be the backbone of a certified grower's farming system:

• Rotations and diversification are key principles in an ecological farming system.

• In an annual cropping system: Legumes used as green manures, cover crops or permanent understory improve fertility; Allelopathic crops that exude toxins from their roots can suppress weeds and insect pests; Diversity of crops in both time and space prevents insect and disease buildup and provides a hedge against poor market conditions for any one crop.

• In a perennial or permaculture system: Cover crops are used to hold the soil, improve fertility and provide habitat for beneficial insects; A diversity of plants including polycultures, hedgerows and windbreaks help ensure that no one factor such as a pest or a weed can throw the system off balance.

• Pest-free and weed-free fields are neither always possible nor economically and ecologically desirable. Learning the thresholds for tolerable levels of weeds, insects, birds and rodents takes time and experience and is an on-going process.

• Varietal selection should look beyond maximum potential yield and consider insect and disease resistance, nutritional quality, flavor and positive response to lower inputs of nutrients and water.

• Pest problems can be minimized by proper timing of plantings and the use of trap crops to attract pests and beneficials alike.

• Materials are not used as the primary management strategy, but rather as an aid to resolving a specific problem until the farm system can be brought back into balance.

• Livestock management is based on good nutrition, animal stress reduction, preventive medicine and other means not dependent on drugs or pesticides.

• Livestock breeding selects for disease resistance.

The Living Soil

The condition of the topsoil affects not only productivity, but also its stability and resistance to erosion. In nature the soil surface is protected by vegetation and plant debris, which is continually being drawn into the soil by worms and other fauna. Rain percolates gently through this layer to the soil beneath. Due to its high organic content the surface soil acts like a sponge, retaining part of the moisture and allowing the surplus to filter slowly into the subsoil and then into streams, rivers and eventually, the sea.

Traditional farming practices served to protect this surface layer. Stubbles left after the cereal harvest shielded the ground from the force of winter rains. Organic matter was maintained in soil by the regular application of farmyard manure, the ploughing in of green-manure crops and short-term grass leys and by the grazing of livestock. The soil was thus able to withstand, without damage to its structure, the folding of sheep in winter and exposure to the elements during fallowing for weed control in summer.

Autumn sown cereals have largely replaced spring sown ones with the consequence that most soils no longer have the protection of stubbles and straw residues during the winter. The contribution of farmyard manure and green-manure crops to soil organic matter is now, on average, very small. Artificial fertilisers and slurry from livestock yards, which contains very little humus, is the main nutritive supplement for the soil. The result of these changes, together with the use of heavy compacting machinery, is a soil that is less permeable to rain; consequently water runs directly off the surface into water courses. During prolonged and heavy rainfall there is a risk of serious soil erosion; siltation of ditches, watercourses and reservoirs; deposition of soil on roads; and of flooding.

The lower layers of soil below farmland are also endangered by changes in farming practices. A healthy soil contains numerous worms, insects, slugs, centipedes, spiders and other organisms. These creatures, notably worms, play an important part in maintaining the health of the soil through maintaining an open texture; drawing down surface litter and making it available for plant growth; and through bringing up plant nutrients from the subsoil.

Additionally, a soil in good heart supports large populations of fungi, bacteria and other micro-organisms, which play a vital part by 'fixing' nitrogen from the atmosphere, regulating the supply and balance of plant nutrients and facilitating their absorption by plant roots.

In general, levels of soil organic matter have fallen to very low levels through intensive farming practices including the use of heavy dressings of chemicals and pesticides. Since the 1950's, the annual use of fertilizers and pesticides has increased tenfold to over two million tons today.

During this period average yields have increased greatly. However, on some soils increasing applications of chemicals have been found to be required to maintain these increased yields, because of the deterioration in the condition of the soil. Weed infestations have in some cases become severe. If a farmer wishes to convert such soils back to an organic system, it is found that the full rehabilitation process can take 10 years or more, before the structure and the soil flora and fauna are fully restored. The complete rehabilitation of an eroded soil takes far longer and, in severe cases, is an impossible task.

We must ensure that the knowledge and experience that maintained former traditional farming systems is not lost. We may come to depend upon it once again---quite soon.

Soil Erosion: Is it a threat to our future?

The greatest irreversible change arising from the long-term practice of unsustainable farming methods is the loss of topsoil. Since agriculture began, soils in many parts of the world, have been destroyed and replaced by degraded vegetation, bare rock or sand deserts. The civilizations that they sustained have disappeared also. In recent times, one of the most dramatic examples of erosion occurred in the 1930s, where large areas of once productive land were destroyed by gully erosion and reduced to a dustbowl. In the Roman period North Africa was described as the breadbasket of the Empire; it has since been replaced by the Sahara Desert. At the present time Africa is losing thousands of hectares of productive land each year through water and wind erosion. In some places blowing sands are engulfing fertile irrigated lands.

In temperate zones the processes of oxidation of organic matter and soil erosion are slower than in the tropics, where temperatures are higher and rainfall is more intense. However, in temperate zones, the rate of soil formation is also lower. Some soils in Britain are subject to annual losses of 20 tonnes per hectare. In both temperate and tropical zones, the first symptom of soil degradation is the reduction of levels of organic matter in the soil.

A general decline in soil organic matter has been in evidence for many years. This change reduces the stability of soils, and predisposes it to erosion by water and by wind. Silt-laden water running off arable fields is a common sight, especially after heavy rain. Wind erosion is an increasing hazard, especially where prairie conditions have been created by the removal of hedges and woods. The fine silt is blown away in dry windy conditions and either deposited nearby on roads and ditches, or swept up into the atmosphere. Many tons of topsoil can be lost in this way in the course of a season -- soil that may take hundreds of years to replace through natural processes.

Farming systems that incur rates of soil loss that are greater than that of formation, are obviously not sustainable, however long it may take to reach the point of uneconomic exploitation.

from an article at www.landheritage.org.uk