Abstract: In order to clarify the effect of no-tillage plastic film and stubble with residues on soil nitrogen supply in dryland maize growing season. The differential distribution of total nitrogen, alkali nitrogen（NO-3-N）, ammonium nitrogen（NH+4-N） and nitrate nitrogen in the 0~100 cm soil layer were analyzed of two cultivation modes include double-bed and fur-row-sowing with full plastic film mulching (CK), no-tillage plastic film and stubble with residues (T). The results showed that: NO-3-N and NH+4-N gradually decreased from the surface to bottom of the soil, and the main changes was in 0~20 cm soil layer. Compared with CK, T treatment decreased NO-3-N by 24.7%~59.9%, and decreased NH+4-N by 4.4%~46.8% in 0~10 cm soil layer of whole growth period. In 0~20 cm soil layer of T, the decrease of NO-3-N and NH+4-N were 20.5%~58.0% and 8.7%~31.7%, respectively. After maize jointing stage, there was a significant cumulative effect of NO-3-N and NH+4-N of T in 20~100 cm soil layer. The total nitrogen and alkali nitrogen gradually decreased from the surface to bottom of the soil. The tillage modes had an impact on the vertical distribution characteristics of total nitrogen and alkali nitrogen content. Compared with CK, T decreased the alkali nitrogen by 0.3%~26.0% in 0~20 cm soil layer and by 17.7%~23.8% in 10~20 cm soil layer after flowering stage. Therefore, the supply of NO-3-N and NH+4-N in the 0~20 cm soil layer in T was significantly lower than that of CK, and resulting in insufficient supply of alkali nitrogen after maize jointing stage. This was the reason for maize premature aging in the late growth stage of no-tillage plastic and stubble with residues cultivation.

Key words: dryland maize, no-tillage plastic and stubble with residues, NO-3-N, NH+4-N, available nitrogen

摘要： 为了明确留膜留茬免耕栽培模式对旱地玉米生长季土壤氮素供应动态的影响。试验设2个处理：全膜双垄沟播栽培（CK）、留膜留茬免耕栽培（T），分析了玉米生长季土壤全氮、硝态氮（NO-3-N）、碱解氮、铵态氮（NH+4-N）在0~100 cm土层分布的差异。结果表明：NO-3-N和NH+4-N含量变化主要集中在0~20 cm土层，整体上从表层到底层依次降低。玉米整个生育期0~20 cm土层，T处理的NO-3-N和NH+4-N含量显著低于CK，0~10 cm土层降幅分别为24.7%~59.9%和4.4%~46.8%，10~20 cm土层降幅分别为20.5%~58.0%和8.7%~31.7%；玉米进入拔节期后，20~100 cm土层T处理的NO-3-N和NH+4-N含量出现明显的累积效应。栽培方式改变了全氮及碱解氮含量的垂直分布特征，不同栽培方式各生育时期全氮及碱解氮含量整体上随土层深度增加呈下降趋势，以表层0~20 cm含量最高。在0~20 cm土层，T处理的碱解氮含量在玉米进入抽雄期后显著低于CK，0~10 cm降幅在0.3%~26.0%，10~20 cm降幅在17.7%~23.8%。因此，玉米整个生育期0~20 cm土层留膜留茬免耕栽培的NO-3-N和NH+4-N供应量显著低于全膜双垄沟播栽培，引起玉米拔节后碱解氮含量供应不足，是留膜留茬免耕栽培玉米生育后期出现早衰的原因之一。

关键词: 旱作玉米, 留膜留茬免耕, 硝态氮, 铵态氮, 碱解氮