Cultivating organic cotton

Appropriate techniques, besides water management and plant density, can successfully regulate insects and pests

Organic cotton is grown without the use of synthetic fertilisers, insecticides or pesticides. Seeds are sown directly into the soil but in less amounts as compared to conventionally grown cotton. This helps reduce competition for sunlight, water and nutrients, and also encourages boll development. It also means that less insects will be required for pest management. During the preparation of the subsoil, compost is embedded into the soil in order to enrich it with organic nutrients such as nitrogen, phosphorous and potassium. No extra fertilisers are used. However, if soil analysis indicates a requirement, some fields may need to apply an additional fertilising substance that is organically accepted by certifying agencies. An effective fertilising programme will always take into account three key elements: farmer’s experience; cost; and cropping sequence. After the initial preparation is done, techniques such as crop-rotation and cover-cropping along with pre-irrigation can help manage soil fertility.

Crop irrigation is carried out from May to August depending on the delivery process, number of applications, and amount of surface water applied. The total amount of water required is determined by soil type and soil moisture. For cotton, furrow irrigation is the accepted method of application. Growth regulators and defoliants are applied to the field before the harvest season to promote uniform boll maturity and leaf drop. This is because leaves often tend to clog machine pickers, impede harvest and taint cotton lint. Hence, these procedures are employed to improve the efficiency of mechanical harvesting and ginning. Even though zinc sulphate may be used as a foliar application to help in boll maturation, it may not necessarily produce the same effects as synthetically created compounds. As a result, harvest may be restricted.

Harvesting season occurs in October and early November, depending on seasonal conditions. During this time, the unloading of seeds is greatest when the moisture content of the crop is low — 12% or less —which allows for cotton to be stored for a longer time before ginning without compromising quality or grade. It must not be forgotten that there are many other factors that influence crop yield including location, weather conditions, pest control techniques, irrigation and soil fertility.

Crop rotation and diversification are essential for organic cotton growth. These methods can help boost economic stability by spreading production risks across a larger number of crops. The crop mix should ideally be complementary so that procedures may be completed in a timely manner with no competition for manpower, equipment and managerial knowledge.

Planting cover crops can help with crop yield. Root growth and the return of organic matter to the soil can improve water penetration as well as infiltration. Grass is mainly beneficial in soil promotion as it is able to strengthen soil stability due to its fibrous root structures. Moreover, microbial activity has also been demonstrated to change soil stability when promoted by cover crop root secretions and organic matter. This is crucial as nutrients are freed when bacteria degrades organic matter. However, it must be kept in mind that planting cover crops may also have negative consequences such as the capability to attract arthropod pests.

The identification, monitoring and prevention of pests are crucial stages in the production of cotton. This is specifically true for organic production since organic growers do not approve of most of the pesticides that are currently used by convention cotton growers. Instead, treatments like biological control along with natural insecticides are utilised to diminish pest damage as well as to reduce short-term economic risks. These treatments — in concurrence with crop rotation, diversification and other cultural techniques — have the ability to minimise and control disease, weed and pest problems.

The threat of disease occurrence is the same for both organic as well as conventional cotton growers. The following techniques are used to abate disease prevalence: i) preventing plantation in cold wet soils; ii) improving field drainage and modifying irrigation practices so that saturated soil does not offer a promising environment for disease; iii) encouraging crop rotation.

Insects like Lygus bugs, spider mites and cotton aphids are nourished on plant foliage, small bolls and squares. When the populations of insects are in abundant amount, plant growth will weaken and diminish. As a result, economic damage occurs and entire yields are reduced. In organic cotton fields, insects and mite pests are controlled by monitoring the level of natural predators and parasites, along with the discharge of biological control agents. The field is often checked 2 to 3 times a week to expel any excess predators, parasitoids or parasites present. This helps minimise and control their population.

Predatory mites and the Trichogramma wasp have been discharged in the past to significantly reduce the population of insects and caterpillars in cotton fields. Sulphur dust is also spread along the fields to suppress mites when necessary. Furthermore, trap crops are sown in nearby fields to attract pests and insects. These appropriate management techniques, besides water management and plant density, can successfully regulate insects and pests accordingly.