Climate- Cotton is a crop of subtropical climate. Cotton needs on an average a minimum temperature of 600 F for germination, 70 -80 0F for vegetative growth, 80-900F with cool nights during fruiting period.
An annual rainfall of at least 50 cm is minimum requirement for cotton unless it is grown on irrigated soils. Ultimately rains and the heavy humid weather during later stages of cotton season may spoil the produce, lower its ginning properties or promote attack of insect, pest, diseases. So weather should be clear at harvesting because rain at this stage will discolour the lint and reduce its quality.
Soil- Cotton needs a soil with a excellent water holding capacity and aeration and good drainage as it cannot withstand excessive moisture and water logging. The major group of soil for cotton cultivation are the alluvial soils, black soils, red sand loam
Seed rate and spacing- Depending upon the variety, soil type, the cultivation on practices and method of sowing, seed rates and spacing have been recommended.
The seed rate of 15-25 kg/ha and spacing of 75-90 cm between the rows are generally recommended for irrigated conditions. For rainfed deshi-cotton seedrate of 12-16 kg/ha and spacing 45-60 cm between rows are adopted. For rainfed American cotton seedrate is 12-16 kg and spacing is 60-75 cm between the rows.
Optimum sowing time- Sowing of crops depends upon water resources. If irrigation facilities are available the crop should be sown in April, especially American cottons, otherwise it must be sown just after the monsoon starts but not later than 15th July. Sowing in rows can be done either by drilling, dibbling, or placing the seeds in furrows behind the country ploughs.
Manures- Fern yard manures rarely applied to cotton in the states of Punjab, Haryana, Rajasthan, Madhya Pradesh. In Maharashtra the cotton crop is manured with farm yard manures once in 3-4 years @ 12-15 tonnes/ha.
Fertilizers- For rainfed crop 20 kg of N 18 kg of P and 78 kg K is economical Nitrogen is applied in split doses, half dose at the time of sowing and other half as top dressing thinning or just before flowering.
For irrigated cotton the dose is double.
Water requirement- In northern India the irrigated cotton crop is mostly sown after a preliminary heavy irrigation and second light irrigation is given three to four weeks after germination. Subsequent watering depends upon the nature of the soil and the weather conditions.
Flowering and ball formation are the critical stages from the point of irrigation. Inadequate irrigation stages during this stages leads to a heavy shedding of flower buds and bolls.
In Maharashtra cotton is sown on ridges and given two light irrigations immediately. Then after one or two irrigations are given and the crop is sustained till the onset of monsoon. Depending upon the rains one or two irrigations are necessary.
Generally crop needs 6-8 irrigations and 600-800 mm of water during its lifetime.
Cultivation practices: Before sowing the soil is first given a heavy irrigation followed by one or two ploughings then the soil is planted with wooden plank In Central India the rainfed cotton, field is harrowed for 3-4 times.
Interculture- Weeding is followed after 30-40 days of sowing subsequently hoeings are given to control weeds. Thinning of cotton is a special feature of the irrigated crop.
Diseases and pests- Cotton aphids cotton jassides are controlled by spraying Malathion 0.08%.
Cotton leaf roller, spotted boll corn, pink boll corn are controlled by dusting crop with 10% carbonyl where red cotton bug and dusky cotton bug are controlled by dusting 5% B.H.C.
Optimum harvesting time- Cotton is harvested in three or more pickings taken suitable intervals. The season of harvesting varies with of sowing, duration of variety. Generally the crop is sown in June-September and is September-October is harvested from November to March to June respectively. Well dried bolls are picked.
Varietal Improvement- New improved cotton varieties were released for cotton cultivation in various tracts in India. Out of them, 320-F in Punjab, H-14 in Haryana, Deviraj and Digvijay in Gujrat and MCU-2 in Tamilnadu are noteworthy. In second plan Badnawar-1 in Madhya Pradesh, Buri-14 in Maharashtra, MCU-3 in Tamilnadu are some newly released strains.
In Third plan Gujrat-67, U-797, J-34, MCU-4, AK-235, AK 277 and Buri-1007 are other for cultivation