Study On Nitrogen Absorption And Volatilization Loss Characteristic Of Cotton In Xinjiang

Xinjiang is the largest and the most suitable production base for cotton goods in China.One of the important features is a large quantity of nitrogen inputs of cotton production in Xinjiang.Recent studies have shown that the usage rate of nitrogen on cotton in Xinjiang is about 30-50%.But the way about loss of nitrogen fertilizer in cotton fields is not clear.Some nitrogen may be lost through plant evaporation.There were many reports about wheat,rice,soybeans and other crops for nitrogen volatilization losses.But there were less for cotton crops.In this study,the ¹⁵N tracer technique was used.Through the water culture experiment,the chemical form and volatile character was reserached for the ground part of cotton plant N volatilization loss;Through field experiment,plant nitrogen content was monitored on the entire growth period of the cotton.The results verified that there was the nitrogen volatilization loss on the cotton growth later period.The study on the nitrogen nutrition of cotton will improve the theoretical basis on nitrogen using efficiency.The main conclusions are as follows:(1) Water culture experiment showed that the chemical form of cotton plant N volatilization loss from ground part was NH₃,N₂O and N₂.Under the experimental conditions,the average evaporation rate of ammonia,N₂O and N₂,for cotton plants in the flowering period,was 34.46μg/g·h,5.1549μg/g·h and 4.6143μg/g·h,respectively.For cotton plants in the bell period,the average evaporation rate of ammonia, N₂O and N₂,was 115.19μg/g·h,5.9628μg/g·h and2.9252μg/g·h,respectively.(2) Through water the culture experiment,¹⁵N content of the old leaves,dead leaves and plants was 3%-5%of the total usimg content.In the flowering and boll period,content of the nitrogen volatile loss for the ground part of the cotton was 72%and 75%of the total using content,respectively.(3) At field experiment of monitoring ground and drip irrigation cotton,during the whole growth period,nitrogen content of the cotton organs was:leaf＞stem＞root.From the flowering to boll period,the ratio of the nitrogen accumulated was 3:4:3.(4) Through estimating in the cotton field,nitrogen loss content of the ground and drip irrigation was 35%and 13%of the total using content,respectively.