关键词: 旱作玉米, 留膜留茬免耕, 硝态氮, 铵态氮, 碱解氮

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