Introduction
Senna is a small branched shrub with field life of 5-7 months. It is a drought tolerant crop and can be grown either as pure crop or mixed with other agricultural crops. Economic parts are leaves and pods. Major constituents are Sennoside A, B, C, D. Senna leaves and pod-shell contains the laxative principle which is extensively used as bulk laxative in medicine.
Soil and climate
Well drained sandy or sandy loam soils with pH 7.0 – 8.5. It can also be grown on poor and marginal soils. It is a hardy warm weather crop grown under rainfed and irrigated conditions
Seed rate and spacing
About 15 – 25 kg/ha of seed is required. The seeds are scarified with sand or can be soaked overnight in water to get good germination. Seeds should be sown in beds at a spacing 45 x 30 cm or 60 x 30 cm or 60 x 60 cm during February – March or June – July. Water logging should be avoided.
Inter cultivation
The first weeding should be done at 25-30 days after sowing, second at 75-80 days and third 110 days after sowing.
Harvesting
It can be retained as perennial crop. Stage of harvesting is judged by full grown, thick and bluish coloured leaves. First harvest of leaves and pods are done at 2 months after planting and subsequent harvest at 30 days interval. Leaves are spread on clean floor under shade in thin layers and stirred frequently. In 7-10 days, the leaves dry which is indicated by yellowish green colour. Pod bunches are hung in ventilated rooms for drying which is completed in 10-12 days. Then the pods are beaten and seed is separated. The produce is finally packed in Hessian bags.
Yield
Yield of dried leaves : 1 t/ha.
Yield of dried pods : 75 – 100 kg/ha