Castor (Ricinus communis)

 

Land Requirements Land to be used for seed production shall be free of volunteer plants. In addtion the field should be well-drained and soil well-aerated.  
Isolation Requirements Castor is an often corss-pollinated crop. Cross-pollination by wind varies from 5 to 36 per cent according to the prevailing climatic conditions. For pure seed production, the seed field must be isolated from other vareity fields and of same vareity not conforming to varietal purity requirements of certification at least by three hundred metres for foundation seed class, and one huncred and fifty metres for certified seed class.

 

Cultural Practices

Time of Sowing The sowing time in most of the States is June to July. In Bihar (Rabi crop) castor is sown in September to October. In Gujarat, plating is done in August to September and in Karnataka it is sown in April.
  


Preparation of Land Castor is a deep-rooted crop. Therefore, deep ploughing has been found very useful. One deep ploughing followed by two to three harrowings is sufficient to bring the field to the desired tilth.


Source of Seed Obtain breeder's/foundation seeds from source approved by a seed certification agency.


Seed Rate 11 to 18 kg per hectare, varies upon spacing, seed size andmethod of sowing. For rainfed crops a seed rate upto 33 to 44 kg is also practised.


Method of Sowing The crop is planted in rows either by drill, or behind the plough in furrows. the depth of seeding is 7.5 to 10 cm.


Fertilisation The crop responds well to organic manures. the rate of fertiliser application varies considerably in different States and ranges from 20 kg to 80-100 kg per hectare for nitrogen, 10 to 40 kg phosphorus and 10 to 40 kg potash.


Spacing Row to row                      90cm(annual varieties)
Plant to plant                     45 to 90 cm


Irrigation The number of irrigations required vareis with the rain. Usually two tothree irrigations during the entire crop season may be required. Adequate moisture in soil at the time of flowering is necessary.


Interculture The castor field must be kept weed-free for the first sixty days after planting. Two to three weedings/hoeings are sufficient to keep the field clean. Application of 2-4D, or triflurelin (3 to 4kg per hectare) is also recommended forcontrolling annual dicot weeds.


Insect and Disease Control Adopt recommended IPM methods


Roguing Remove all offtypes before flowering. The diseased plants affected by Phytophthora blight and Cercospora leaf spot should be rogued out as soon they are noticed, and preventive plant protection measures adapted immediately to check further spread.


Harvesting and Threshing

The fruits are ready for picking in November. The picking continues until April, because thecapsules mature unevenly due to sequential development of racemes. The fruits should be gathered when they start turning light yellow and placed in piles to dry in the sun unitl they blacken. Later the seeds are beaten out with sticks, winnowed and screened to remove husks, dry skins and soil pebbles. Before storage, the seed must be dried to eight per cent moisture content.


Seed Yield Eight to ten qtl per hectare. High yielding varieties if managed well may give 15 to 20 qtl per hectare seed yield under irrigated conditions.