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→Propagation and planting
For mechanized cropping under rain-fed conditions, field preparation starts by ploughing deep enough to break any compact layers. Castor requires a moist topsoil for germination and early growth for a longer period than maize or cotton. In dry regions where total rainfall is low, ridging is recommended. Smallholders usually intercrop castor in annual crops or plant it along the edges of fields or as a shade crop e.g. for ginger, turmeric or sugarcane.
Castor is propagated by seed. In spot-sowing 2–3 seeds are planted per hole at a depth of 3–8 cm; alternatively castor is sown in rows. The weight of 1000 seeds is 100–1000 g. Short-cycle cultivars may be grown in sole cropping as a second crop. In intercropping, distances between rows of castor may be as much as 4–5 m, and it will receive the treatment of the main crop. With dwarf cultivars in sole cropping, planting may be at 1 m row distance. Closer spacing can result in considerable damage to branches during weeding. Recommendations for in-row spacing range from 25–35 cm for dwarf, to 30–40 cm for larger cultivars, or about 25,000–30,000 plants/ha for crops grown in locations with 750–900 mm rainfall. Under irrigation, row width may be determined by the system of water delivery and where water is not limiting 30, 000–40,000 plants/ha is feasible depending on the cultivar.
== Management ==