渭北旱地夏闲期秸秆还田和种植绿肥对土壤水分、养分和冬小麦产量的影响

研究渭北旱地秸秆和绿肥还田土壤水分、养分的变化，对黄土高原旱区作物高产稳产有重要意义。以夏季裸地休闲为对照，研究免耕小麦秸秆还田和种植豆科绿肥及二者混合对渭北旱地冬小麦产量，播前、开花期和收获后土壤水分、硝态氮、铵态氮、有效磷和速效钾数量的影响。试验结果表明，秸秆还田和种植绿肥对冬小麦籽粒产量和生物量无影响；夏闲期种植绿肥和秸秆＋绿肥处理使播前和开花期60—160cm土壤贮水减少；种植绿肥处理表层0-20cm土壤硝态氮在播前显著增加10．7kg·hm-2，收获期增加18．4kg·hm-2；开花期种植绿肥土壤有效磷提高43．4kg·hm-2，收获期有效磷数量仍较对照高24．4kg·hm-2；秸秆还田和种植绿肥对土壤铵态氮和速效钾没有显著影响。可见，一年秸秆还田和种植绿肥对冬小麦产量没有产生显著影响，种植绿肥降低了土壤贮水，但提高了表层土壤硝态氮和有效磷数量，不同栽培方式对土壤铵态氮和速效钾含量没有影响。

Effects of Straw Mulching and Planting Green Manure on Soil Water, Nutrient and Winter Wheat Yield on Weibei Plateau, China

Effects of straw mulching and planting leguminous green manure on soil water and nutrient on Weibei Plateau is recognized to be of great significance for the high crop yield in dryland area. With bare fallow in summer as control, field experiments were carried out to study influences of wheat straw mulching, green manure planting and their mixture under no-tillage on the winter wheat yield, and the contents of soil water, nitrate-N, ammonium-N, available phosphorus（P） and potassium（K） at pre-seeding, flowering and post-harvest on dryland of Weibei Plateau. Obtained Results showed that straw mulching and green manure planting had no effect on the winter wheat yield and biomass. Planting green manure and straw＋green manure in summer fallow period decreased water storage in 60-160cm soil layers in stages of preseeding and flowering. Compared with the control, planting green manure significantly increased soil nitrate-N in 0-20 cm soil layer by 10.7 kg. hm-2 at pre-seeding and 18.4 kg. hm-2 at harvest. At flowering stage, planting green manure enhanced the amount of available P in surface soil by 43.4 kg·hm-2 and 24.4 kg·hm-2 at harvest. However, straw mulching and planting green manure had no significant effect on soil ammonium-N and available K. Consequently, one-year straw mulching and green manure planting had no obvious effect on the winter wheat yield, planting green manure decreased the soil water storage but increased amounts of soil nitrate-N and available P in the 0-20 cm soil layers, and different cultivation methods had no effect on soil ammonium-N and available K contents.