What Are the Growing Conditions for Cotton? Analysis of the Latest Cultivation Key Points
Cotton is the seed fiber of plants in the Gossypium genus of the Malvaceae family, native to the subtropics. The flowers the plant produces are creamy white or pink. What is commonly called cotton is the fiber inside the fruit that grows after flowering and bursts open when the fruit matures. It likes heat, loves light, tolerates drought, and dislikes waterlogging, and is suitable for planting in loose, deep soil. Now let us take a look at the growing conditions for cotton!
Light Conditions
Cotton is a light-loving crop and is suitable for growing under relatively abundant light conditions. Both its light compensation point and light saturation point are high. According to measurements, the light compensation point of a single cotton leaf is 750-1000 lux, and the light saturation point is 70,000-80,000 lux. Under normal circumstances, the suitable range of light intensity for cotton leaves is 8000-70000 lux, and within this range the photosynthetic intensity increases as light intensity rises.
Moisture Conditions
Cotton growth requires absorbing water from the soil, and the physiological water requirements differ at each growth stage. From sowing to emergence, a water content of 70-80% of field capacity in the 0-20 cm soil layer is suitable; at the seedling stage, a water content of 60-70% of field capacity in the 0-40 cm soil layer is suitable; at the early bud stage, a water content of 65-75% of field capacity in the 0-60 cm soil layer is suitable; after the full bud stage, a water content of 70-80% of field capacity in the 0-80 cm soil layer is suitable and must not fall below 60-65%; at the boll-opening stage, the relative soil water content should preferably remain at 55-70%. According to relevant research, over the entire growth period a cotton field consumes about 2/3 of its water through transpiration and 1/3 through soil evaporation.
Soil Conditions
Cotton growth and development require water and nutrients, which are mainly obtained from the soil through the root system. The needed temperature and air are partly drawn from the soil, and at the same time the soil's mechanical support is needed for growth. The physical, chemical and biological properties of cotton field soil largely constrain the yield and quality of cotton. Soil moisture, nutrients, temperature, air, salinity and alkalinity content, and texture all have a great influence on cotton growth.
Heat Conditions
The two stages of early and late cotton growth are the most sensitive to heat conditions. Sowing to emergence mostly requires 7-20 days and an active accumulated temperature of 160-320°C. When the air temperature remains above 20°C after sowing, seedlings can emerge in 7-8 days. If the air temperature is unstable after sowing, even though it averages 15-17°C, about 20 days are needed for emergence. The lower the daily average temperature, the more accumulated temperature is needed from sowing to emergence. The heat conditions from flowering to boll opening not only affect cotton yield but also seriously affect cotton quality. In years when the interval from flowering to boll opening is markedly prolonged in the same region and for the same variety, the accumulated temperature during this stage is higher, and the cotton yield and quality decline noticeably.