亚洲一区欧美在线,日韩欧美视频免费观看,色戒的三场床戏分别是在几段,欧美日韩国产在线人成

In order to define the effect of straw returning with nitrogen application on soil properties and water use efficiency of maize in Yanghuang Irrigation Area of Ningxia, the treatment with uncovered straw and nitrogen application rate of 333kg/hm2 was taken as the control (CK), the effects of different nitrogen application rates of SR+N0 (0kg/hm2), SR+N1 (150kg/hm2), SR+N2 (300kg/hm2) and SR+N3 (450kg/hm2) on soil bulk density, water, nutrient, maize grain yield and water use efficiency were investigated. The results showed that the straw returning with nitrogen application could improve soil bulk density and total porosity in tilth soil (0~40cm), and the SR+N2 and SR+N3 treatments were the best. The mean tilth soil bulk densities with SR+N2 and SR+N3 were significantly increased by 8.0% and 8.8%, the mean total soil porosities were significantly increased by 11.4% and 12.5%, compared with CK. Straw returning with nitrogen application was useful for increasing soil organic carbon and total nitrogen at 0~40cm soil layer, and the contents of soil organic carbon, total nitrogen with SR+N2 and SR+N3 were significantly increased, compared with CK. The ration of carbon to nitrogen was decreased with the increase of application rate of nitrogen under the condition of straw returning. The enhancement of soil fertility was the highest at SR+N2, with significant increase of the contents of soil alkelineN, available P, and available K by 33.6%, 47.0% and 30.8%, respectively. The SR+N2 treatment had better soil moisture conservation effect at middle and later growing stage of maize, and it also achieved the higher maize grain yield and water use efficiency improvement. The twoyear mean maize grain yield and water use efficiency with SR+N2 were significantly increased by 33.9% and 26.2%, respectively, compared with CK. Through the twoyear results it was found that straw returning with application of nitrogen can not only effectively improve soil physical properties, but also significantly increase the soil nutrient contents, regulate the ration of carbon to nitrogen, and showed the better soil water conservation ability, therefore significantly increased crop yield and water use efficiency in Yanghuang Irrigation Area of Ningxia. The straw returning with application of pure nitrogen for 300kg/hm2was the best.