| With the different amount of organic manure and straw returning measures, the effect of organic fertilization on the dry soil for soil water storage,physical and chemical properties,crop growth and yield,soil nutrient and WUE was researched for consecutive three years in this study. The results had a great theoretical and practical significance for establishment and perfection of soil capacity expansion and technology to enhance rainfall use efficiency model in semi—arid regions. The main conclusions were as follows:1. The results showed that the application of organic manure can significant increase soil water storey between 0—60cm soils than CK treatment in the wheat period of regeneration, the increasing amount of water storage from high fertility to low higher than CK,24.75mm,15.77 mm and 13.68mm higher than CK respectively; The soil—moisture storage was increase significantly than CK between 0—200cm soil layers of wheat in the filling period, high fertility had the highest increase amplitude and it was 17%. The effect of different straw returning was obviously increasing the soil water storage in 0—200cm layer at pre-sowing than CK. From high fertility to low higher than CK, the increase amplitude was 30.17mm,31.13 mm,32.83 mm higher than CK respectively.2. The application of organic manure can increase nutrient obviously. Compare with CK, organic matter increased 7.8% Total-N increased 7.3% on average, and the other nutrient had no significant difference with CK treantment. Available-P increased 40.4.3%, available-K increased 15.3% compare with CK, and they had sensitive change than others. The meature of straw returning made organic matter and available-K increase significantly, the condition of other nutrient have similar regularity compare with organic fertilizer treatment. The total nutrient changed obviously in shallow soil. and the change trend will be stable in the deep soil. 3. The change of content of soil urease and alkaline phosphatase had great variation in organic fertilization treatment between 0—20cm soils.There was an inconsistent activity change about soil urease,alkaline phosphatase,invertase and catalase in the past 3 years. The meature of long-term fertilization can significantly enhance the activity of soil urease,alkaline phosphatase and invertase.Moreover.it is more significant increase the activity of soil urease,alkaline phosphatase and invertase through higher fertility.The activity order of soil urease and alkaline phosphatase through different treatments just follow the amount of organic matter from high to low.The effect of organic fertilizer for the activity of invertase was little,and the activity of invertase had little difference by different amount of organic matter treatments.4. The results show that:compared with CK, soil bulk density decreased 0.89% in organic manure treatment after 3 years, soil porosity increased slight; the treatment of straw returning decreased soil bulk more remarkably, decreasing range was between 0.7%—6.6%, soil porosity increased slight. Soil bulk density decreased 8.4%,7.7%,5.9% on average respectively than CK in 0～40cm soil layer in 2009.Compare to the condition before wxpexperiment start, soil bulk density have decreased after 3 years organic fertilizer treatments,but it have not significantly difference between the 3 treatments in 0～20 cm soil layer in 2009. In 20～40 cm soil layer,middle treatment had significantly decrease than CK.5. The results showed that the proportion of the bigger soil aggregates significantly increased by organic fertilizer treatments and there was a positive correlation between organic fertilizer amount and the proportion. The stability of soil aggregates was improved by organic fertilizer treatment; The contents of>5 mm,2～5mm and> 0.25 mm water—stable aggregates in 0—10 cm and 30—40 cm layers of fertilizer treatment increased significantly compared with CK.On the contrary, the contents of 0.5—0.25 mm water—stable aggregates was not significant than CK. The significant difference between these treatments is mainly reflected in> 5 mm and> 0.25 mm aggregates.6. The treatment of organic manure and straw returning made dry matter accumulation higher than low treatment and CK; the treatment of high straw returning and organic manure had a significant difference compare with CK.7. The results of organic fertilization for 3 consecutive years show that, organic fertilizer can increased yield of crops and WUE, increasing range of yield is 6%～12%and WUE is 12.8%～42.0% when planted linseed. and increasing range of yield is13.9%～34% and WUE is 15.5%～43.6% when planted wheat in 2008. Following with the fertilization amount form high to low, WUE of winter wheat under different fertilizer treatments increased by 38%,38 %,23% respectively compare with no fertilizer treatment in 2009, WUE of winter wheat in high and low fertilizer treatment is significant higher than CK.Compare with CK,the yield of corn have increased between 4.8%～18.1% and WUE have increased between 10.3%～12.9% on the treatment of straw returning,when we planted millet,its increasing range of yield is 10.6%～67.3%, WUE is 1.2%～59.4%. Follow the amount of straw returning from high to low, compared with CK,the yield of corn increased 58.3%,36.7% and 5.4% respectively; WUE of corn increased 38.5%,31% and 0.9%respectively in 2009.
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