Sunn Hemp Production Guide: A Step-By-Step Cultivation Practices

Sunn Hemp (Crotalaria juncea) is a fast-growing, annual summer legume with a strong taproot and branching system. Its yellow flowers give it its name, and it is one of the two primary cover crops grown worldwide. Sunn Hemp is utilized for green manure, livestock feed, and as a non-wood fiber crop. In India, it is used for making ropes, twines, nets, handmade paper, and canvas. It is also an excellent source of fiber for high-quality tissue paper, cigarette paper, and currency paper.

Sunn Hemp Production Guide

Best Package and Practices of High-Production Sunn Hemp

For high-production Sunn Hemp, it is recommended to use quality seeds, plant appropriately, and maintain proper soil fertility. The ideal planting time is during the warm season, and the crop can be harvested after 60-90 days. Sunn Hemp should be sown in well-drained soil and irrigated regularly. Proper crop rotation and weed control are also crucial for maximum yield. The harvested crop can be used as green manure, livestock feed, or a source of fiber for paper production.

Land / Field Preparation and Soil Requirements for Sunn Hemp

Sunn Hemp thrives on most soil types except acidic, alkaline, and waterlogged soils. It prefers well-drained loam or sandy loam soils with a pH range of 6.0 to 7.5 for optimal growth and root nodulation. Soils rich in phosphorus and calcium are most suitable for cultivation. For land preparation, one plowing followed by two to three harrowing is sufficient to achieve good tilth. The land should be leveled with a gentle slope to facilitate drainage, and adequate moisture is required during sowing for seed germination.

Temperature, Climatic, and Rainfall Requirements for Sunn Hemp

Sunn Hemp is best suited to tropical and subtropical climates and is grown in different seasons across India. In northern India, it is grown in summer and rainy seasons, while in the southern parts, it is grown in the rabi season. The crop requires at least 400 mm of evenly distributed rainfall during the growing season. Sunn Hemp grows well under long-day fiber production conditions but requires short-day seed production conditions. It germinates quickly at soil temperatures of around 14°C but prefers warmer weather (30-40°C) for optimal growth.

Propagation Method and Seed Quality for Sunn Hemp

When planting Sunn hemp, it’s advisable to use a grain drill or broadcast method. The seed should be planted one inch deep or less in loose soil. The broadcasting method may require a higher seeding rate.

Seed Treatment for Sunn Hemp

Sunn Hemp seeds can be treated with cowpea inoculant to enhance nitrogen fixation.

Seed Rate and Spacing for Sunn Hemp

For Sunn Hemp, the recommended seed rate for seed production is 3-5kg/ha and 5-10kg/ha for cover crop purposes. Higher seed rates are advised in cooler climates since the plant may not branch as much. It is best to sow with no-till and press wheels. Seed depth should be between 2-5cm, with 2-3cm ideal. However, Sunn Hemp is a strong germinator and can come up from depths below 5cm if required.

Sowing Method for Sunn Hemp

When planting Sunn Hemp, it’s advisable to use a grain drill or broadcast method to plant the seed at a depth of one inch or less in loose soil. However, the broadcast method may require a higher seeding rate since many seeds may not penetrate to an appropriate depth.

Crop Rotation and Intercropping in Sunn Hemp

Sunn Hemp can be intercropped with tree crops, allowing direct Sunnlight access when grown in aisles, alleys, or row middles. As mulch, it can be cut and spread within tree rows. Sunn Hemp has proved successful as an intercrop in several systems, such as carambola, coffee, citrus, papaya, and pineapple. Additionally, it can be combined with other legumes such as American joint vetch, cowpea, hairy indigo, and slender leaf rattlebox to benefit nutrient cycling and soil microorganisms, increase biomass, and improve overall diversity. Sorghum sudangrass’s inclusion scavenges excess soil nitrogen to produce biomass with a high C: N ratio.

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Manure & Fertilizer Applications in Sunn Hemp

Sunn Hemp can increase nitrogen fixation through symbiosis, but its fiber yield can benefit from applying 20 kg N/ha. To promote good nodulation and fiber yield, 40 kg P2O5 and 20 to 40 kg K2O/ha should also be applied based on soil conditions.

Weed Management and Herbicide Application in Sunn Hemp

Sunn Hemp’s fast growth smothers most weeds except nut sedges, and only one wedding is needed in problem areas during the early stages. However, the common weed Hirankhuri (Convolvulus arvensis) requires manual weeding to prevent hindering crop growth and fiber extraction.

Water Management in Sunn Hemp

Sunn Hemp planted during the kharif season with the onset of monsoon usually does not require irrigation. However, if the crop is sown as a summer crop in mid-April, it will need around 4-5 irrigations at 15-20 days intervals, depending on the prevailing soil and weather conditions.

Disease Control in Sunn Hemp

Sunn Hemp is susceptible to two common diseases: vascular wilt caused by Fusarium udum Butt: f. sp. crotalaria, and leaf curl virus caused by Geminivirus, which spreads through whitefly. To control vascular wilt, neem cake can be applied before sowing, and intercropping with Jowar and Til is effective. Seed should be treated with Bavistin. To prevent leaf curl virus, endosulfan 35 EC can be applied at a 2 ml/liter rate for whitefly control.

Pest Control in Sunn Hemp

The Top Shoot Borer is a damaging pest that affects Sunn Hemp during the monsoon season. To manage this pest, deep plowing in summer, early sowing in April/May, and soil application of radon-3 G followed by two sprayings of Carbaryl-50WP are recommended. Another common pest is the Hairy Caterpillar, which can be controlled by spraying Endosulphan at 15-day intervals, three to four times. These measures help to prevent damage to the foliage and seeds of the plant.

Harvesting and Threshing of Sunn Hemp

Sunn Hemp sown in summer is ready for harvest in 90-100 days, while the kharif crop should be harvested at the 50% flowering stage. The plants are harvested with a sickle and tied in small bundles for retting and washing. The upper tender portions can be used for cattle feed or green manure by incorporating them into the soil.

Sunn Hemp Yield per Acre

Sunn Hemp fiber yield ranges from 5 to 10 quintals per hectare in various parts of the country. However, improved practices can produce up to 12 quintals of fiber and 50-60 quintals of sticks per hectare.

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Conclusion

Sunn hemp is a highly versatile and profitable crop grown in various cropping systems. With proper cultivation practices, including appropriate seed rate, nutrient management, disease and pest control, and harvesting techniques, farmers can achieve fiber yields ranging from 5 to 10 Q/ha.

Sunn Hemp Production Guide: A Step-By-Step Cultivation Practices