Effects Of Planting Densities On Cotton Photosynthesis Production, Plant Nutrition Absorption And The Cotton Field Microclimate

The experiment has been conducted at a place that was early maturity cotton of Aksu in 2007-2008.To study the effect of five densities (9.0, 13.5, 18.0, 22.5, 27.0×104 plant/ha) on growth and development,yield and quality,approach the characteristic from photosynthetic,nutrient uptake, microclimate in cotton field,the aim was provide a theoretical basis of technology system and and application of high-density high-yield cotton cultivation in Xinjiang.The results showed that:1. It was not significantly of the density of cotton reproductive process,but it was significantly of individual cotton bolls temporal and spatial distribution in different densities,the cotton plant height was dwarfed, stem diameter was attenuated, stem leaves and vegetative shoot growth were restrainted with the density of cotton, the boll concentrater on lower fruit branch, effective boll number per plant, boll weight single downward trend also, Density of all treatment,the highest yield was 3247.4 kilos per hectare that density was 180,000 plants per hectare. Density from 90,000 to 180,000 plant per hectare, fiber length,micronaire value and strength were increased with the density,and micronaire value and strength would decreased when the density more than 225.000 plant per hectare.2. During cotton boll to theopeningofaboll, photosynthetic rate of leaf area index,the fourth leaf count from top in main stem, numeric of boll-bearing branch and the fourth leaf count from top , and drops was gentlerly.In dry matter accumulation, dry matter archery target accumulation quantity occupied about 50% during cotton boll to theopeningofaboll, also the cotton reproductive organ does the material to accumulate the best time,at th same time, dry matter accumulation of groups and reproductive organs were higher than other treatment, and a positive correlation with yield, the largest margin more than 20%.3. The plant nutrient forms to the cotton yield has certain function, the nutrient accumulates along with the cotton birth advancement increases unceasingly, before the present flower bud, the rate of rise is slow, enters after in June, accumulates the speed to speed up, the nitrogen, the phosphorus, the potassium content increase stably. The accumulation speed in sees about the flower bud latter 70-90 days the maximizing, 90 days later starts to drop. The abundant bell - boll opening, the nitrogen, the phosphorus, the potassium community content is highest by 180,000 plants per hectare density processing, and in the boll opening time, in 181,000 plants per hectare density processing bell's nitrogen, the phosphorus, the potassium accumulation quantity is very high, forms consistently, the correlation coefficient with the output reaches 0.85.4. After theopeningofaboll of cotton, the high production processing was higher than other processing obviously in a different level's width line of transmittance, the 20cm crown level transmittance maintains about 10%, 40cm crown level transmittance about 20%. Next, the flowering season and sees the cotton wool time cotton and kapok corolla level air temperature to be high, the flowering season the time interval planting density high processing temperature was also noon high, otherwise early, late. After seeing the cotton wool, noon the stage air temperature processes by the middle density to two nearby processes reduces. After this indicates the boll opening, middle density processing still could have the sufficient light to be hot, has guaranteed the cotton later period the boll opening. After the relative humidity diurnalvariation is drops first elevates, the flowering season relative humidity is high, and changes is small, the boll opening time, crown level 20cm place, the late suitable humidity is early high, presents between two side high schools the low phenomenon, between the width line does not have the obvious difference, this favors the cotton boll opening, reduces the rotten bell's occurrence effectively; On the soil moisture, there is loss of water more and more with increasing density at bud stage, the water is important for cotton between flower to full boll stage. in each treatment, the water of A3 increases quickly and conserve good in this period.The cotton field daily average ground temperature is been big the land geographical position influence, but is been small the density influence.