The organic matter, which only accounts for 0.5 to 5 % of the soil, is of crucial importance for a soil’s fertility and water retention capacity. It ensures a good porosity and good infiltration of water. Organic matter particles keep the soil moist for a long time and retain essential nutrients for plants. Moreover, organic material hosts numerous beneficial soil organisms that improve soil fertility. Many soils on conventional farms lack organic matter due to intensive cultivation and an overuse of mineral fertilizers.
In order to obtain good and stable soil fertility, organic farmers ensure a continuous supply of organic material to the soil. The most important source are residues of the crops grown on the field itself, such as leaves, stalks and roots, and they are applied to the soil in the form of green manure, mulch or compost. Other sources include organic manures, oil cakes and liquid fertilizers such as (biogas) slurry.
Composting transforms organic material from the farm, such as crop and fodder residues, weeds, leaves, and dung or kitchen waste, into high-value natural manure. Compost, applied to the field as basal application or as a top dressing, provides the crop with well-balanced nutrients and helps increase soil organic matter content.
Integrating animal husbandry into cotton production provides the farm with high-quality manure. Correct storage of the manure (not too moist, not too dry) is essential in order not to lose nutrients. The manure should preferably be integrated into the compost along with other organic materials. Lots of peasant families use cattle as their farm “mechanisation”.
Crop rotation and mixed cropping are essential elements in organic cotton production in order to maintain soil fertility and ensure balanced nutrient content in the soil. Crop rotation helps prevent leaching from soils, a build-up of critical pest populations and also diseases and weeds. As the organic cultivation method dispenses with mineral nitrogen fertilizers, it is important to grow cotton in rotation with leguminous plants such as beans, peas or soya beans. They fix nitrogen from the air and make it available to the plant, thus improving soil fertility.
To maintain soil fertility, water and wind erosion should be prevented. Applying compost and practising mixed cropping contribute significantly to making soils less prone to erosion. As further measures, green fences or stone walls can be built around fields.
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"Forstering the Uptake of Organic Cotton in the Market" held in October 2016 (summary in the library)