【摘要】 为揭示宁夏扬黄灌区秸秆还田配施氮肥对土壤性状与玉米水分利用效率的影响,在秸秆全量还田(9 000 kg/hm2)条件下,设置4种不同纯氮施用水平:SR+N0(0 kg/hm2)、SR+N1(150 kg/hm2)、SR+N2(300 kg/hm2)和SR+N3(450 kg/hm2),以秸秆不还田施氮量333 kg/hm2为对照(CK),研究秸秆还田配施氮肥对土壤容重、含水率、养分含量、玉米产量及水分利用效率的影响。结果表明,秸秆还田配施氮肥可改善耕层(0～40 cm)土壤容重和孔隙状况,以SR+N2和SR+N3处理效果最优,耕层平均土壤容重分别较CK降低8. 0%和8. 8%,土壤总孔隙度分别较CK提高11. 4%和12. 5%。秸秆还田配施氮肥有利于提高耕层土壤有机碳和全氮含量,随施氮量的增加土壤碳氮比降低,其中以SR+N2和SR+N3处理效果最优。SR+N2处理改善土壤肥力效果最优,其土壤碱解氮、有效磷、速效钾含量分别较CK提高33. 6%、47. 0%、30. 8%。SR+N2处理在玉米生育中后期具有较好的蓄水保墒效应,玉米增产和改善水分利用效率效果最优,两年平均玉米籽粒产量和水分利用效率分别较CK提高33. 9%、26. 2%。通过两年研究发现,在宁夏扬黄灌区,秸秆还田配施氮肥可有效改善土壤物理性质、增加土壤养分含量、调节土壤碳氮比、增强土壤的蓄水保墒能力,从而显著提高玉米籽粒产量和水分利用效率,以秸秆还田配施纯氮300 kg/hm2效果最优。更多还原

【Abstract】 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/hm2 was taken as the control(CK),the effects of different nitrogen application rates of SR + N0(0 kg/hm2),SR + N1(150 kg/hm2),SR + N2(300 kg/hm2)and SR + N3(450 kg/hm2) 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% and12. 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 twoyear 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/hm2 was the best.更多还原