Introduction of Castor Cultivation:- Basically , Castor (Ricinus communis L.) is grown for its seeds. The oil extracted from Castor seed is being used widely for various purposes. It is used as a lubricant in high-speed engines and aero planes, in the manufacture of soaps, transparent paper, printing-inks, varnishes, linoleum and plasticizers.
Castor seeds are also being used for medicinal and lighting purposes. The Castor may be used to make manure and plant stalks as fuel or as thatching material or for preparing paper-pulp. Castor leaves are being fed to silkworms.
Castor belongs to the family of “Euphorbiaceae and genus of “Ricinus L.”. Castor is indigenous to the Eastern Africa, south-eastern Mediterranean Basin and India, but is grown throughout tropical regions and sub-tropical regions of the world. Castor seeds contain between 45 % and 60 % of oil that is rich in triglycerides, mainly ricinolein. Commercial growing of Castor seeds is very much successful due to its demand in local and international markets. In India, this crop is grown where annual rainfall is expected below the national average and the soil is not that fertile.
Castor Oil Uses and Benefits:- The following are some of the uses and benefits of Castor oil.
Note: This plant is also the source of the deadly poison ricin. Do not eat the unprocessed seeds. Do not use any of its products without consulting your doctor.
Castor Varieties:- The varieties (cultivars) of castor differ in the branching habits of plant, colour of the stem and branches, the nature of capsules , duration, the size of seed and oil content. Here are some of the high yielding castor varieties available in India; NPH-1, GAUCH-4, YRCH 1,TMV 5, TMV 6, CO 1 and TMVCH.
Climate Required for Castor Cultivation:- Castor crop can be grown from sea level to altitudes of about 1000 meter (m.s.l). Castor crop requires a hot, dry climate with annual rainfall of 500-800 mm, of which 500-600 mm is needed during the first 3 months of crop growth. Castor is an ideal crop for marginal lands of the Dry Zone where it can be grown under both rainfed and irrigated conditions. This crop is sensitive to high humidity and high temperatures above 40°C and impacts the crop yield.
Soil Requirement for Castor Cultivation:- Generally, Castor is cultivated in lands which are not suitable for commercial farming. Castor can come up well in soils that are not that fertile and soils having less annual rainfall. Castor seeds can be grown on a wide range of soils which are fairly deep and well drained. The most suitable soils for castor cultivation are deep, moderately fertile, with slightly acidic conditions and well drained sandy loam soils. The ideal soil pH of soils should be around 6.0 for better yield. However, it can be cultivated on soils with pH range of 5.0 to 8.5.
Land Preparation for Castor Cultivation:- Land preparation is an important task in Castor cultivation. Give 3 or 4 deep ploughings to loosen up the soil as this crop requires well pulverized 40 cm deep loose sub-soil for good seed germination. Land or seed bed should be weed free and any weeds from previous crops should be removed. The clods should be crushed by using a country plough or harrow with onset of monsoons.
Seed Rate in Castor Cultivation:- A seed rate of 10 to 12 kg is more than enough to cover 1 hectare land. Again, seed rate depends on cultivar (Variety) and [sowing method.
Seed Treatment in Castor Cultivation:- It is recommended to treat the seeds with Carbendazim @ 2 grams/kg of seed for preventing seed borne diseases like root-rot and Alternaria blight. Soaking the seeds in water for 18 to 20 hours is advised. In rainfed situations, seed priming with 1% Kcl for 3 hours and sowing 7 days before onset of monsoon is recommended.
Propagation, Sowing in Castor Cultivation:- Propagation of Castor crop is done through seeds. Castor bean is usually planted just before the rainy season in the month of June. However, it can be cultivated throughout the year in areas where irrigation facility is available. The spacing adopted generally ranges from 90-120 cm between rows and 40-60 cm between plants in the row. The seed should be sown either by plough furrow or with a seed-drill or by hand-dibbling.
Gap Filling in Castor Cultivation:- Gap fill should be carried out on the 15th day of sowing and simultaneously thinning should be done leaving one healthy plant.
Irrigation in Castor Cultivation:- Rainfed crops don’t need any irrigation. However, in irrigated crop, water should be provided weekly twice. Frequency of irrigation depends on the soil type, climate and crop stage.
Weed Management in Castor Cultivation:- Weed control is very important in any crop as it impacts the overall yield as weeds compete for nutrients, fertilizers, manures and water. One or two weedings and hoeings with bullock-drawn implements should be given and sometimes, the plants should be earthed up. Chemical weed control like weedicides can also be effective to prevent the weed growth. Apply pre emergence herbicide Pendimethalin @ 3 liter/ha or Fluchloralin @ 2 liter/ha on 3 days after sowing followed by hand weeding twice on 21 st & 40th day after sowing the seed.
Inter-crop in Castor Cultivation:– Farmers can earn some extra income by going for inter crops. Groundnut / Peanut, black gram, green gram can be cultivated along with Castor crop. For every row of Castor, 6 rows of peanut or black gram can be cultivated. Intercropping of castor with Green gram or Black gram in 1:2 ratio is recommended for rainfed condition. Intercropping of castor with onion in 1:2 ratio by adopting 1.5 x 1.0 m spacing is recommended for irrigated condition.
Manures and Fertilizers in Castor Cultivation:- Spread 12 to 13 tonnes/ha of well decomposed farm yard manure (FYM) or compost evenly on the main field before last ploughing and incorporate in to soil by working a country plough. Apply 25 kg sulphur/ ha through gypsum at the time of last ploughing for higher castor yield. Timely application of manures and fertilizers ensures the good crop growth and yield. The castor crop requires a fertilizer dose of N: P: K as 40:40:20 kg/ha. As a basal application, apply full dose of ‘P’ and ‘K’ and half dose of ‘N’.The remaining half dose of ‘N’ should be applied 1 month after sowing when the soil moisture is adequate.
Pests and Diseases in Castor Cultivation:– The common and serious pests in Castor cultivation are capsule-borer and semi-looper. To control these pests, dusting BHC 10% in early stages or spraying 0.1% Carbaryl on the crop should be carried. The other soil borne diseases like seedling blight and Alternaria blight are also major concerns in Castor crop. Water logged areas; low-lying areas should be avoided to prevent the seedling blight. To control Alternaria blight.
Harvest in Castor Cultivation:- The maturity of the crop depends on the variety. Most of the improved cultivars mature in about 140 to 175 days. The easy indication of Castor maturity is when 1 or 2 capsules in bunch show signs of drying. The whole cluster should be removed and stacked. The harvesting of unripe capsules has an adverse effect on the oil content of the seed and these should be avoided. It is recommended to collect the fruits when they ripen. After collecting entire crop, it should be dried in sun for couple of days and threshing should be done by beating the dried capsules with the help of stick. In rural areas, farmers use bullocks for threshing these crops. Winnowing should be done in the usual manner. One can use Castor Sheller as well to separate the seeds.
Yield in Castor Cultivation:- Generally, yield of any crop depends on factors like cultivar (variety), soil type, irrigation, climate and cultural practices. On an average the following yield can be obtained.