Medicinal Plants

Senna (Cassia angustifolia)

Introduction


  • Senna, is a small, perennial, branched, drought resistant undershrub growing to a height of 60 - 75 cm.
  • The leaves and green, immature pods contain glycocides like sennocides A and B, which are extensively used as a laxative particularly for habitual constipation.
  • The crop is cultivated in Tirunelvelly and Ramnathapuram districts of Tamil Nadu, Guntur district of Andhra Pradesh in India and in Sudan. Leaves and pods are exported from India.
  • The crop can be grown as an irrigated crop throughout Andhra Pradesh on marginal red laterites, red soils, coarse gravelly soils, alluvial loams and on rich alayey soils, ranging in PH from 7.0 to 8.5.

Varieties

  • There are two varieties namely, local which is early flowering and ALFT 2 which is late flowering. The yields from these varieties are identical.
  • Sona is a high yielding variety released by CIMAP.

Cultivation

  • The crop is propagated through seeds. 15 kg seeds are required per hectare. The land is prepared by ploughing twice, harrowing and levelling. 5 - 10 tonnes of farm yard manure, 250 kg of single superphosphate, 70 kg of muriate of potash and 25 - 30 kg of zinc sulphate per hectare are applied bassally.
  • The seeds are sown in 30 -45 cm rows at the end of rainy season (September). After germination plants are thinned to maintain 30 cm plant to plant distance.
  • In Tamil Nadu, the crop is seeded either in February - March (irrigated) or in November (rainfed). The crop is very sensitive to high soil moisture, therefore, only light irrigations are to be given initially at 6 - 7 day and later 15 - 20 day intervals. A total of 5 to 8 irrigations are to be given.

Interculture - Fertilizers

  • First weeding is done within 6 weeks of swoing, subsequently after each harvest of leaves / pods.
  • The crop is fertilized with 90 kg urea per hectare 30 days after sowing and 45 kg urea each time after first and second leaf harvests. Micronutrients and growth regulators may be sprayed for good crop growth.

Pests and Diseases

  • Leaf spot caused by Alternaria alternata and leaf blight caused by Phyllosticta spp. cause severe damage to the crop through leaf drop.
  • Spraying of Carbandazim (0.03%) or Dithiocarbamate (0.03%) at fortnightly intervals for 3 times is recommended. Damping off of seedlings caused by Rhizoctonia bataticola is common in fields affected by stagnating moisture.
  • Seed treatment with Thiram or Captan (2.5 g / kg seed) before sowing is advocated.

Harvesting - Profits

  • The crop flowers 2 months after sowing which are removed to encourage side branching. Fully grown, thick and bluish coloured leaves are stripped manually. Golden yello coloured immature pods are harvested.
  • First leaf harvest is taken 90 dyas after sowing, subsequent two harvests are obtained at 30 - 40 day intervals. Pods are harvested with second and thrid leaf harvests.
  • The leaves and pods are shade dried for 5 - 10 days, pressed into bales and stored.
  • The crop yields 1500 - 2000 kg dried leaves, 150 - 200 kg dried pods and a net profit of Rs. 25000 - 30000 per hectare per year
  • If the crop is raised purely under rainfed conditions, the yeidls and profits would be approximately 50 % of the irrigated crop. It can also be grown as a perennial crop.
  • Developed markets are available in Tamil Nadu and private individuals are encouraging cultivation with buy - back arrangements in Andhra Pradesh. Farmers are advised to take up cultivation after ascertaining the market for the produce.

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