Castor

Nutrient Management

Introduction

  • The castor plant grows well on a wide variety and soil types the nutrient status of which is infinitely variable.
  • Thus the rate, type of added plant nutrients and methods of application vary as greatly as the conditions under which the plant is grown.
  • The crop is tolerant to low rainfall, not low fertility.
  • It has been calculated that a 1700 Kg per hectare soil yield removes the equivalent of 50 kg nitrogen 20 kg of phosphoric acid, and 16 kg of potash per hectare, another estimate states that a yield of 2000 kg of seed and 1333 kg of hulls removes 80 kg nitrogen, 18 kg phosphorous, 32 kg potash, 12 kg calcium and 10 kg magnesium per hectare.
  • Soil reaction has a major influence on the availability of plant nutrients, and those most often applied are nitrogen, phosphate and potassium.
  • Nitrogen availability is optimal between pH. 6.5 and 8.0, phosphorous has a narrower range of maximum efficiency between pH 6.7-7.5, potash is the least affected, serious diminution in general availability becomes apparent only when the pH value is below 5.5. but on certain alkaline soils potash may also be deficient between a pH of 7.5- 8.5. In general fertilizers applications have little effect on oil content of seeds, however oil formation in the seed is more active between twenty to seventy days after flowering and throughout this period the nutrient supply should be adequate.

Organic Manuring

  • Incorporation of farm yard manure or compost at the rate of 5-6 t/ha in the last ploughing is advantageous for improving the soil properties and also to ensure better supply of micro nutrients.

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Major Nutrients

Nitrogen

  • Adequate supply of nitrogen is essential for optimum leaf growth,with dark green colour.
  • It promotes branching, seed setting and seed filling.
  • Deficiency of this element will result in poor growth, pale green foliage, less branching or poor seed setting.
  • Nitrogen recommendations vary with the region and system of cultivation.
  • As castor is grown both as rainfed and irrigated crop in the country, the response to applied N varies under rainfed and irrigated conditions.
  • In regions of rainfed cultivation the response again differs with amount of rainfall and its distribution.

  • For rainfed castor, application of 20 kg N/ha as basal dose followed by top dressing with an additional 20 kg N/ha each at 35-40 and 65-70 days after sowing gives good economic response.
  • In the event of a dry spell during first 50 or 55 days apply the first top dressing of N at the time of initiation of secondaries as and when rains are received.
  • Besides a basal dose of 40 kg N/ha, irrigated castor of more than 180 days duration requires the additional application of N @ 20 kg/ha at each successive picking starting from 90 days or harvest of first order spike i.e., at intervals of 30 days.
  • Avoid higher levels of N than recommended, as it results in excessive vegetative growth and weak root system.
  • The N fertilizer for both rainfed and irrigated crop, should be placed in continuous band at 5-6 cm / depth and 5-7 cm away from crop row.
  • However, for hybrids and desi varieties planted with wider inter and intra row spacing, ring placement method is preferred.

Phosphorus

  • It is essential for root growth, seed and fruit development and for early ripening.
  • It is a constituent of several organic compounds including oils and amino acids. P-compounds viz., ADP,ATP act as energy store house in plants.
  • Phosphorus deficiency retards plant growth, root growth and delay flowering.
  • The phosphorus recommended for rainfed castor varies from 15 to 40 kg P2O5 / ha as per fertility and moisture retainment status of soil.
  • The water soluble single super phosphate is generally preferred for castor.
  • In addition to Phosphorus, this fertilizer also supplies sulphur and calcium.
  • Entire phosphorus along with basal dose of N has to be applied at the time of sowing and the method of application is by placement.

Potassium

  • It plays a significant role in the activation of several enzymes involved in production and translocation of photosynthates to storage organs, besides regulating transpiration, and providing resistance to pest, disease and environmental stress.
  • It also helps in enhancing the quality of crop.
  • The most widely used potassium source is muriate of potash, as it is water soluble and less costlier.
  • The recommended doses of potassium for both rainfed and irrigated are 20 and 40 kg K2O / ha respectively.
  • In case of rainfed castor, entire potash should be as basal by incorporation.
  • In case of irrigated castor half of potassium as basal and the remaining half along with nitrogen as top dressing.

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Time, Dose and Method of Application

  • The method of placement and the distance between fertilizers and seed may vary considerably depending on the crop, soil, region and fertilizer end.
  • Mixing fertilizers directly with the seed, or using planters which place seed and fertilizer in contact in the seed bed, should be avoided.

  • This particularly important with castor seed, the thin testa of which is easily damaged, causing seed to rot in the ground, reducing germination, and resulting in poor or uneven stands.
  • The depth of placement of the fertilizer affects root development, for roots will proliferate in this region.
  • Deep fertilizers placement also tends to produce a deep rooted plant better able to with stand drought, but since plants can only obtain their main supply and nutrients in solution, the soils in this region must be damp.
  • This potassium allows the developing roots, which are geotropic, quickly to reach the area of nutrient concentration, thus promoting health growth.
  • For rained castor, application of 20 kg N and 40 Kg P205 / ha as basal dose followed by top dressing with an additional 20 kg N/ha each at 30-40 and 65-70 days after sowing gives good economic response.
  • In the event of a dry spell during first 50 to 55 days apply the first top dressing of N at the time of initiation of secondary as and when rains are received.
  • Besides a basal dose of 40 kg N and 40 Kg P205/ha, irrigated castor of more than 180 days duration requires the additional application of N at the rate of 20 kg/ha at each successive picking starting from 90 days of harvest of first order spike i.e. intervals of 30 days.
  • Avoid higher levels of N than recommended, as it results in excessive vegetative growth and weak root system.

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Telangana

Castor

Castor Management