Water management

Critical stages Squaring, Flowering and Boll development

Results in

• Premature flower drop,
• Shedding of squares and young bolls
• Poor development of bolls.
• 700-1200mm water requirement and 2-10 irrigations
• Depending on climatic condition and soil type etc, irrigation at 10-15 days interval for light soils and 15-25 days for medium & heavy soils is normally recommended.

Irrigation

• Improved fiber quality and stable yield– Long and fine fiber
• The cotton plant needs irrigation or water when the leaves turn to a dark or dull bluish green color followed by wilting during the hot part of the day.
• Irrigation in available soil moisture (50 to 75%) is recommended for cotton.
• Cotton irrigated at 75% depletion of available soil moisture results higher yield.
• Generally, furrow irrigation is done.
• No reduction in fiber quality
• Most common and saves more water also controls weeds
• But furrow irrigation is not suitable for very sandy soil due to high intake rate.
• For hybrid- drip irrigation is being popular as it has resulted in better partitioning of photosynthate, greater yield and more WUE.
• Indicator like sunflower and tomato show water stress symptoms.
• Heavy irrigation is given before sowing and then after 3-4 weeks.

Water logging

• This problem is accentuated by rainfall after irrigation, cloudy conditions and inadequate land preparation.
• On heavy clay soils adequate field drainage and slope and a high plant bed height are essential to reducing the effects of water logging.
• It reduces the yield up to 1bale/ha. The general symptom is yellowing of the crop and stunted growth.
• Low fibre strength
• In some cultivars of cotton soil moisture stress during the pre-flowering period was found to stimulate flower initiation and hence increase the number of bolls while in other cultivar boll size was increased. (de Bryn,1964)