Cotton is a Warm season
(tropical) crop.It can be profitably grown in regions with rainfall of
850-1100 mm, but economic yields can not be realized in the region with a
rainfall less than 500 mm.50cm of well-distributed rainfall is
necessary for higher yields. In general,
temperatures above 35 degree C are not desirable for cotton growing,
however, when the moisture supply is favourable, the cotton plant is
capable of enduring without permanent injury, very high temperatures
(upto 43-45 degree C) for short periods. If these high temperatures
persist for several days, however, the yields will be adversely
affected.High light intensities throughout the growing period are
essential for satisfactory vegetative development, for minimal shedding
of buds and bolls and hence for higher yields.Cotton Crop can be grown
up to 1000m altitude.
Soil requirements
Cotton
has a wide range of soil adaptation and is grown on a great variety of
soils. Highest yields of cotton are usually obtained on alluvial soils.
High yield of cotton is dependent on favorable air and moisture regime
in the soil-hence the importance of soil structure and texture.For a
deep-rooting crop such as cotton, soil depth is also an important
factor and shallow soils are not suitable. Cotton is not unduly
sensitive to soil reactions; it can be grown on a variety of soils with
pH ranging from 5 to 8 and above. Cotton is generally considered as
fairly tolerant to salinity. Uptake of Sodium by cotton has been found
to be much lower than would be expected from its relative abundance and
availability in soil and water as was shown by the low accumulation of
sodium in both tops and roots. This indicates that the relatively high
salt-tolerance of cotton may be at least party due to the presence of
some selective mechanism that enables cotton roots to restrict sodium
absorption. With irrigation facilities, cotton is usually cultivated on sandy loam to loam soils.