Soils and climate

It is grown on a wide range of soils from medium to heavy black soils, mixed red and black soils or in alluvial soils but requires well drained aerated soils with a rough seed bed. It does fairly well in black cotton soils and medium clay soils. The PH range is wide between 5.5 and 8.6, but the optimum is 5.7 to 7.2.

	It does not withstand water-logging, saline and alkaline conditions.
	It requires cool dry climate, frost-free with dew. It cannot tolerate heavy rains, hence is unsuited for hot tropics.
	It is grown on residual soil moisture where the rainfall ranges from 400 to 700 mm and unreliable.
	The average air temperature varies from 25 to 300C for good crop growth.
	Nights must be warmer with 20 to 250C temperature.
	It is distinctly a long day plant requiring 12 to 16 hours of bright sunshine per day.
	It responds to vernalization (hastens flowering by cool temperature). The optimum temperature regime is 240 to 320C.
	In Andhra Pradesh (AP) this crop is mainly grown in fatile heavy black soils with the residual moisture and the dew fall in winter season.
	Optimum period of sowing in AP is in the month of September for getting higher yields. However, the varieties to be selected for September sowing should be tolerant to root rot disease.