Castor

Water Management

Introduction

  • The irrigation of castor especially the dwarf hybrids, requires considerable skill to obtain maximum yields.
  • The plant is extremely sensitive to excess soil water at all stages of growth.
  • In areas where there are common high winds in dry season, the crop is more liable to uprooting.
  • Standing water also increased the fungal infections, especially if it is in contact with the stem at a soil level.
  • Young seedlings are very susceptible to various collor rots, and pre-planting water applications are to be preferred to immediate post emergence application.
  • Castor being a deep rooted crop, can extract water from considerable depth in the soil.

  • Individual irrigation may thus be relatively large and therefore less frequent irrigations, a subsequent reduction in transit losses.
  • Where the length of the growing period is limited, initiate the onset of flowering by creating a slight water stress in the plant may be desirable.
  • Irrigation should cease some three to four weeks prior to harvest.
  • Varieties, which remain dwarf in habit when rain grown may grow much larger under irrigation, take longer to mature, and flower over on extended period.
  • A check to growth, by withholding water for a short period prior to flowering, can reduce the vegetative phase and induce more rapid and even flowering in these types.
  • Varietal trials should therefore be as comprehensive as possible, to select those most suitable area and irrigation system.

Top

Irrigation Prospects

  • The number and intensity of irrigations depend on specific soils, their water holding capacity and the crop season in question.
  • As compared to heavy soils, light textured soils require more frequent irrigations.
  • Kharif season crop essentially grown as rainfed crop.
  • The crop growth and yields are satisfactory if the onset of rainfall and its amount and distribution over the crop period is normal.
  • However, if the crop is exposed to prolonged drought during reproductive phase, one or two supplemental irrigations either at primary spike development or secondary spike initiation/development will help in enhancing the yields.
  • The kharif crop should be protected from excess moisture during periods of heavy and continuous rains particularly in heavy soils by providing surface drainage, to drain out excess moisture from seed bed.
  • During rabi the number of irrigations may go upto 6-8 while in summer as many as 12-15 irrigations are required at an interval of 7-10 days depending on soil type and prevailing weather conditions.
  • The first irrigation is given as pre or post sowing irrigation to ensure better germination, emergence and stand establishment, and this irrigation is given so as to bring the top 90 cm, soil layer to field capacity.
  • The second irrigation is generally given at 3-4 leaf stage, the third at 6-8 leaf stage.
  • The subsequent irrigations are given with 15-20 days interval depending on soil and climatic conditions.
  • The most critical period for moisture is the terminal bud initiation to full flowering of primary spike.
  • Hence, at this stage adequate moisture in seed bed should be ensured by proper scheduling of irrigation.
  • The consumptive use (Cu) in medium red loam soils of Telangana region is 500 mm.
  • Furrow irrigation system is ideal for castor sown in ridge and furrow type of seed bed, as this system is the simplest system and also highly efficient, especially under undulated lands or undeveloped topography.

Top

Irrigation Schedule

  • In India castor is normally grown as rainfed crop in both the Kharif and Rabi seasons, but may irrigated if water is available especially when inter cropped.
  • Depending on the soil type, a Kharif crop will require a minimum of 500-700mm in total of rainfall and irrigation water for optimum yields.
  • Whenever there are prolonged dry spells during grand growth period, one protective irrigation either at primary spike development or secondary spike initiation / development will greatly improve the yield.
  • Under intensive management, all currently recommended popular, medium, long duration hybrids / varieties require seven irrigations in sandy loams of Gujarat and six (180 days duration) in the red soils of Karnataka, Telangana and Andhra Pradesh.
  • For realising the full productivity potentials, the first irrigation should be applied at around 55 days or around full flowery of primary spike.
  • The subsequent irrigations may be given at intervals of 20 days after first irrigation, so as to ensure availability of adequate moisture for the development and different order of spikes.

Top

Telangana

Castor

Castor Management