Cultivation

Cultivation

    Soil
    Senna is a hardy plant and thrives on a variety of soils ranging from sandy loam to lateritic soils. In southern Tamil Nadu, the crop is grown on poor and marginal lands under rainfed condition. The soil type in this region is sandy to red sandy soil, with a pH of 7-8.5. In areas of Ottapidaram, Vilathikulam, Sattur and Virudunagar, senna is cultivated traditionally under black cotton soils.

    Climate
    Generally, the crop requires an all-round warm and dry weather conditions. It is very sensitive to heavy rainfall, especially at the time of seed sprouting to young seedling stage. Temporary water logged conditions due to continuous rain and low temperature besides, inclement weather at harvest are unsuitable for its cultivation.

    Propagation
    Senna can be cultivated both as rainfed and irrigated crop, however, in most parts of southern districts, rainfed cultivation dominates and as such, there are two growing seasons, which coincide with the monsoon rain. The first commences with the onset of south west monsoon in June-July and the second during November-December, receding with North east monsoon rain. Wherever irrigation facilities are available, senna can be raised during January-February as irrigated crop.

    Seed treatment and sowing
    The crop is raised from seeds. Since the seeds have a hard and tough seed coat, a certain amount of abrasing of its surface is necessary to induce germination. This is achieved by pounding the seeds lightly with coarse sand in a mortar.
    A traditional method of seed treatment for removing the hard seed coat is mixing the required quantity of seeds with dry and pure sand in the ratio of 1:3 and is gently beaten. Later the seeds are soaked in water for 10-12 hours and then used for sowing. This practice gives about 90 % germination. The seeds exhibit dormancy for 2 months. The land should be thoroughly ploughed, at least two times, and properly leveled for ensuring good drainage. The farmers usually divide the land into small fields enabling for draining the excess rain water and then broadcast the seeds for raising the rainfed crop.
    Under irrigated condition, a uniform spacing of 45x30 cm is recommended. Small beds are first prepared and shallow straight lines are formed at 45 cm apart and seeds are dibbled at a depth of 1-2 cm. The seeds start germination in 5-7 days and complete germination in 15 days after sowing. The seedlings are thinned to have a spacing of 30 cm in between plants within 20-30 days after sowing.

    Manures and fertilizers
    A basal dose of 25 tonnes of FYM, 50 kg N, 25 kg P2O5 and 40 kg of K2O/ha can be applied. Top dressing of 25 kg of N can be applied 40 days after sowing and another 25 kg N after 80 days of sowing. 4-6 irrigations can be given during the cropping period. Continuous rain, water stagnation and excess moisture are not suitable for senna growing.

    Crop rotation and intercropping
    Senna is grown after the paddy and grown as intercrop between rows of cotton, sesamum, chillies, brinjal, okra, mustard and coriander.

    Irrigation
    Senna can be economically grown under rainfed conditions. However, when it is grown as semi irrigated crop, the yield increases considerably and excess irrigation is injurious to the crop.



Last modified: Friday, 22 June 2012, 4:58 AM