Introduction to organic Sesame cultivation
Sesame is a flowering plant in the genus Sesamum and also called benne. Sesame is one of the oldest cultivated plants in the world. Sesame is an annual plant that belongs to the Pedaliaceae family. A native of India, organic Sesame seed is rich in minerals and vitamins and has been used as a healing herb for millennia. Nowadays, organic Sesame seeds are used for cooking or as a condiment, with India, Japan, and China being the most prominent users.
A step by step guide to organic Sesame cultivation practices
Organic Sesame seeds are slightly flat creamy white seeds in appearance with the outer husk removed. Organic standards of Sesame seeds eliminate or minimize the use of synthetic or manufactured inputs and encourage maximum use of local natural resources. Most of the organic Sesame seeds are used for oil extraction and the rest is used for edible purposes.
Soil requirement for organic Sesame cultivation
Organic Sesame varieties have adapted to several soil types. The high-yielding crops thrive best on well-drained, fertile soils of medium texture and neutral pH value. Though, these have a low tolerance for soils with water-logged and high salt conditions. Commercial Sesame crops need 90 to 120 frost-free days. Warm conditions more than 23°C favor growth and yields. While Organic Sesame crops can grow in poor soils, the best yields come from well-fertilized farms.
A wide range of soils are suitable for Sesame cultivation; optimum is well-drained, loose, fertile and sandy alluvial soils that have a pH value between 5.4 and 6.7. Very low pH values have a drastic effect on growth, whereas some varieties can tolerate a pH value up to 8. When irrigated, or in summer rain spells, Sesame grows better in sandy compared to heavy soils. This is due to its sensitivity to high soil moisture content. It is not recommended to plant Sesame on sloping ground, because its need for weed-free seedbeds and its slow rate of early development can lead to erosion. Water-logged, heavy soils, and also soils with high salt contents are not suitable; salt contents that would hardly affect cotton or safflower can already kill off Sesame plants. Shallow soils with impermeable subsoils are also unsuitable.
Crop rotation requirement for organic Sesame cultivation
When cultivating Sesame, the following aspects should also be considered when planning the crop rotation;
- Do not cultivate directly following a fallow period (uneven soil, weed proliferation),
- As weed-free seedbeds as possible (important when selecting the previous crop),
- Previous crops with few demands on the soil,
- Sesame is also a good preliminary crop (it loosens the soil with its taproots, and provides a dense network of roots in the upper layer),
- Well-suited as a second crop (short vegetation period, use of water stored in the soil in a similar way to sorgo, as well as being resistant to drought),
- Resistant against root nematodes,
- Keeps the wireworm (larvae of the beetles belonging to the family of Elateridae) under control in the crop rotation.
Typical crop rotation partners include cotton, grain legumes (peanuts, varieties of beans, soya, etc.), maize, dry rice, and sorgo. Planting a different crop on a specific piece of land each growing season, Crop rotation is essential in organic Sesame production because it is such a useful tool in preventing soil diseases, weed problems, insect pests, and for building healthy soils.
Sesame growing season in India
The proper time of sowing is a must for getting a higher yield. Sesame requires fairly hot conditions and a temperature of 25 to 27°C encourages rapid germination, initial growth, and flower formation. It is cultivated as Kharif (sowing in June-July) crop in North India but in south India, it is cultivated during all seasons.
- kharif (May-June),
- late Kharif (July-August)
- rabi (November-December)
- spring (January-February)
Seed preparation and germination process of Sesame
The Sesame seed must be cleaned thoroughly and treated with one ounce of 75% Captan per 100 lb of seed to prevent damping off. This treatment is particularly important for non-shattering varieties because they are slower to emerge compared to the shattering varieties. Because the seeds of the non-shattering varieties spend additional time in the soil before germination, they require more protection from fungal pathogens in the soil.
Seedbed Preparation for organic Sesame cultivation
Sesame needs a moist, warm, weed-free seedbed. Good drainage is important because the plant is prone to waterlogging at any stage of plant growth. Since Sesame is planted late, several generations of weeds can be killed by repeated tillage before planting.
Diversity in Sesame crop production
Organic farming should contribute beneficially to the ecosystem. Crop diversification is essential for the maintenance of soil health while minimizing nutrient losses and to reduce pressure from insect pests, diseases, and weeds. Diversity in crop production is achieved by a combination of versatile crop rotation with legumes/cereals and intercropping. Sesame + green gram (3:3) and Sesame + cluster bean (3:3) intercropping systems minimize the incidence of leaf roller/capsule borer and bud fly.
Growth drivers for the global organic Sesame market
International demand and export of organic Sesame seeds are steadily increasing in India. The mounting demand for organic seeds in ready to eat products, various food products, bakery products, cosmetics, animal feed products, and medicines is key driving factors for the growth of the global organic Sesame market. Since it is essentially used in food & medicines in developed countries, the importers are insisting on certified organic produce.
Sesame seeds with uniform size, lustrous, bold seed, white, free from flash, low free fatty acids, and free from pesticide residues are preferred in the global markets. The solution for producing and supplying the organic variety lies in identifying suitable production zones, standardization of production technologies, and adoption of organic production methods through contract farming to produce the requisite product.
With a high level of protein content in the organic Sesame seed, the animal feed products are readily aligning to the condiment which is giving an important boost to its demand in the livestock and poultry sectors. Tahini made from organic Sesame seeds is always preferred for their distinctive flavor and low-fat contents.
The growing awareness about the health benefits of organic Sesame seeds consumption is seamlessly driving the global market. The healthy eating trend and the improved usage of Sesame seeds in different food items have significantly contributed to market growth. Also, the sales of organic Sesame seeds through foodservice and retail sectors are increasing. This increases product visibility, thereby, gaining an extra consumer base.
A seed rate in orgaic Sesame cultivation
A seed rate of Sesame is approximately 5 kg/ha is sufficient to achieve the required plant population.
Organic nutrient management in Sesame cultivation
Biodegradable material of microbial, animal, or plant origin produced on organic farms must form the basis of the fertilization programme. Organic standards minimize or eliminate the use of synthetic or manufactured inputs and encourage maximum use of local natural resources. The certification programme shall lay down limits for the use of inputs such as magnesium fertilizers, mineral potassium, trace elements, and manures with a relatively high heavy metal content and, or unwanted substances, e.g. basic slag, rock phosphate and sewage sludge. Manures containing human excreta shall not be used on vegetation for human consumption. There are several organic sources of nutrition and among them green manuring, composting, biofertilizers, vermicompost, and biodynamics are important.
Organic fertilizer requirement in Sesame cultivation
The most important methods of applying fertilizer on organic Sesame cultivations are:
- The use of green manure, the inclusion of legumes in crop rotation, and
- The use of organic manure and compost manure.
Direct application of fertilizer to Sesame is not always necessary; if the soil contains plenty of humus, then fertilizer may already be provided by the previous crop. If fertilizer is to be applied directly, then it is sufficient to do this one month before sowing, as the seedbed is being prepared. When using ripe compost, around 3 t/ha (ca.7 m³/ha) suffice when applied to the seed furrows, or after singling. The supply of phosphorous can be a limiting factor for high Sesame yields. Phosphorous deficiency can be alleviated with bone meal and rock phosphate, which should then be applied before the soil is prepared. The amount and type of phosphate made available to the plants can be improved by the symbiotic relationship with mycorhiza, as this has the effect of increasing the surface area of the root system. By excreting a variety of substances, e.g. phosphatase, it can even make organically bound P available to the plants.
Small amounts of nitrogen-rich organic fertilisers, such as liquid manure, will stimulate the mineralisation of organic substance. When the plants have reached a height of 20 cm, then 20 kg N/ha can be applied. The supply of potassium is usually not a problem. Magnesium and Calcium are of greater importance, as the plants require huge quantities of them, and e.g. can be supplied with magnesium-rich lime (Dolomite).
Organic foliar spraying can provide a large proportion of the fertilizer necessary, and help balance out deficiencies. They are applied in two lots: after singling and as blossoming commences.
- Animal liquid manure is diluted 1:5 with water.
- Cattle manure is dissolved in water.
- Plant extracts: green, chopped legume leaves (e.g.: Crotolaria) and other nutrient-rich plant parts (Lepotea aenstuans, “Chichicaste”) are left in water for a few days to ferment.
- A watery compost extract: the best way is to apply amounts weekly in low concentrations.
Weed management in organic Sesame cultivation
Weed management is one of the key concerns in organic agriculture.
Weed interactions and weed community dynamics can be greatly influenced due to the use of organic manures (a major source of incoming viable weed seeds) in organic farming systems. Generally, all aspects of arable crop production play an important role in the systems approach to weed problems. Within organic systems, the total exclusion of weeds from cropped areas is rarely necessary and weed control can be targeted effectively to key crop growth periods. Other approaches proposed for effective weed management under organic Sesame farming are;
- Use of crop seed free from weed seeds. The first rule for weed prevention and the first step of any good weed management programme is the purchase and planting of clean seed.
- Good crop husbandry practices (tillage, crop diversification, intercropping, planting geometry, etc) contribute considerably to weed control with little extra cost
- Use of thoroughly decomposed compost and other organic manures
- Mulching the soil surface can physically suppress weed seedling emergence
Pest control strategies under organic Sesame cultivation
Pest control strategies under organic farming are largely preventive rather than reactive. The balance of cropped and uncropped areas, crop species, variety, the temporal and spatial pattern of the crop rotation seek to maintain a diverse population of pests and their natural enemies and disrupt the life cycle of pest species. Use of certified seed of resistant varieties, intercropping and crop rotation, summer ploughing, timely sowing, removal of infected plants, keeping field borders free of weeds, etc will help reduce certain insect-pests and diseases.
Sesame Aphids, leafhoppers, and thrips – Aphids, leafhoppers, and thrips are common pests of Sesame. All three are sucking pests that tend to cause stunted growth and may injure buds, thus preventing the development of seedpods. When it comes to managing these small insects, Sesame seed pest control is fairly easy to attain with insecticidal soap spray. However, you may need to spray several times if the infestation is severe. You can also spray infested plants with neem oil, which will smother pests of Sesame.
Leaf roller, cutworms, and other caterpillars – Remove damaged growth. Remove the pests by hand and drop them into a bucket of soapy water. Check the Sesame plants closely at least once every week. Alternatively, treat leafrollers, cutworms, and other caterpillars with Bt (Bacillus thuringiensis), a naturally occurring bacteria that kills the cell membranes in the stomach and digestive tract. However, Bt won’t harm birds or beneficial insects.
Sesame seed pest control
The best method of Sesame pest management is to maintain the best possible growing conditions. Healthy Sesame plants are always more resistant to Sesame pest problems. Maintain healthy, well-drained soil. Sesame plants that grow in poor soil lack nutrition and are more susceptible to pests. Water wisely. Sesame prefers dry conditions and won’t tolerate soggy, poorly drained soil. Occasional light, fast irrigations are beneficial during extended dry periods. Avoid drip irrigation. Apply a balanced, slow-release fertilizer at planting time. If plants look pale green and unhealthy, side-dress the plants with a nitrogen-bearing fertilizer. Keep weeds in check, as Sesame doesn’t compete well with weeds. Additionally, many noxious weeds serve as hosts for aphids and other pests. Keep the garden clean. Sanitation is especially important at the end of the season and in early spring when pests may lie dormant in leaves and other debris.
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Sesame crop diseases and organic methods of prevention
Phytophthora Blight – Crop rotation, use of resistant varieties and use healthy seeds.
Macrophomina phaseolina and Rhizoctonia bataticola (Stem and root rot) – Infection from seeds or soil. Use green manure and encourage nesting of antagonists (ripe compost), use of resistant, or less resistant, varieties (e.g. red shelled varieties).
Fusarium oxysporum (Fusarium Wilt) – Infection from seeds or soil. Non-opening varieties are not as susceptible. If the soil is strongly infected at least a 5-year pause.
Alternaria (Leaf Spot, leaf fleck) – Infection from seeds, use resistant varieties. Varieties completely covered with hair seem to be resistant.
Cercospora Sesame (White Spot) – Infection from seeds and plant residues in the soil. Burn plant residues. Use resistant varieties.
Powdery Mildew – Use resistant varieties. Late ripening varieties are less susceptible. Wettable sulphur (0.2%) or use of sulphur dust 20 kg/ha on the 45th and 65th day after sowing.
Corynespora Blight – Dispose of plant residues. Use clean seeds.
There are several fungal, bacterial, mycoplasma, and viral diseases responsible for the reduction of Sesame yields. Among them, bacterial blight, Alternaria leaf spot, stem and root rot, powdery mildew, and phyllody are major diseases of the crop. A successful approach for disease management under organic farming could be the integration of two or more of the following approaches;
- Cultural practices such as deep summer ploughing, clean cultivation, Phyto-sanitation, and timely sowing
- Intercropping and mixed cropping
- Use of resistant varieties
- Treat the seeds with talk-based formulations of Pseudomonas flurescens and Trichoderma harzianum or T. viridae each by 10g/ kg seed.
- The bio-agent formulations can be used for enriching the FYM by applying 2 kg of Pseudomonas flurescens or Trichoderma harzianum and 50 kg of neem or Pongamia cake to one tonne of FYM. This should be left for 15 days under the shade and then apply uniformly in the field Spray Pseudomonas flurescens 2% about 2 to 3 times to induce disease resistance and control of foliar diseases.
The process of Sesame harvesting
Sesame is ready for harvest 90 to 150 days after planting. In general, the unbranched varieties mature earlier. The crop should be harvested before the first killing frost to get high-quality seeds. At maturity, stems and leaves tend to change from green to yellow to red. The leaves will begin to fall off the plants. The non-shattering and shattering types require different harvesting techniques.
The harvesting happens when the fruit at the base are ripe, the seeds from the fruit get the colour specific to the variety, and the leaves at the base of the stem have fallen. Organic Sesame is generally ready for harvesting between 90 to 130 days after planting.
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