Study On Comprehensive Improvement Techniques Of Ecological System Of Cotton Field In Dry Land

The comprehensive improving on ecosystems of cotton filed on dry land in loess plateau was studied with new material and new techniques. Increasing the WUE of soil was the key of skill. In this article the benefit and mechanism were analyzed from every side. The results showed that:1, The comprehensive improvement techniques (CTI) included five techniques .The first was good strains of seeds of transgenic Bt cotton be used. The second was covering soil with plastic and straw. The third was increasing the density of plant. The fourth was fertilization with organic fertilizer and fertilizer. At the same time, it would decrease the quantity of fertilizer and fertilization was in harmony with N and P and K (N: P: K=1:0.6:0.8).The way of fertilization was coupling water with fertilizer at one time. The fifth was filling water with drip irrigation under plastic film on the crucial period in the bearing time of cotton. At last, we must using DPC on cotton plant.2, The comprehensive improvement techniques(CTI) could enhance the effect of ecosystems of farmland on dry land in loess plateau on ecological and economic and society benefits. At first, the CTI could increase production efficiency of nitrogen (N) by 56.4% and increase water utilize efficiency (WUE) by 36.4%,increase the number of natural enemy colony in cotton field ,and it would decrease the quantity of farm chemical by 75% than common techniques. At second, the CTI could increase productivity by 27.3% and increase the net value by 33.5%, increase the rate between investment and output by 39.9%.At third, occupation coefficient of good strains of seeds would reach to 50% with using CTI in the area; the rate of utilization of straw would increase by 15%.At last, the purpose of adopting the new techniques would reach to 65%.3, The CTI could enhance the yield of cotton. At first, it could increase the temperature and moisture of soil. Secondly, it could enhance the WUE of soil. It could improve the soil and enhance the number of soil microbe strains. It could speed up the course of generational of cotton and increase the accumulation of dry matter of cotton. At last, it could enhance the vitality of cotton boots and enhance the capability of disease-resistance and drought-resistance.