灌水施氮方式对玉米生育期土壤NO_3^--N时空分布的影响

Effects of Different Nitrogen Supply and Irrigation Methods on Spatial-temporal Distribution of Soil Nitrate Nitrogen during Maize Growth

在干旱区大田条件下,以制种玉米"金西北22号"为供试材料,采用交替灌水、固定灌水、均匀灌水和交替施氮、固定施氮、均匀施氮二因素三水平的完全组合方案,在拔节期、大喇叭口期、抽雄期、灌浆期和成熟期对0~100 cm土层分层监测植株正下方、植株正南侧和植株正北侧的土壤NO_3^--N含量。结果表明:监测时期内,植株南、北两侧较植株下和0~40 cm土层较40~100 cm土层的土壤NO_3^--N含量时空分布受灌水施氮方式影响更大。固定灌水固定施氮下,水氮同区时土壤NO_3^--N在施氮侧下移,而水氮异区时土壤NO_3^--N在施氮侧累积。灌浆期,40~80 cm土层的植株下,与均匀灌水相比,交替灌水下不同施氮方式的土壤NO_3^--N含量减少9.9%~14.4%。交替灌水均匀施氮或交替灌水交替施氮使得土壤NO_3^--N在较长时间内维持在0~40 cm土层周围,成熟期二者0~100 cm土层的土壤NO_3^--N残留量相近,但较其他处理减少11.7%~27.3%。综上,交替灌水均匀施氮或交替灌水交替施氮使玉米生育期土壤NO_3^--N含量时空分布比较合理,成熟期土壤NO_3^--N残留量较低。

A field experiment was conducted to investigate the effect of varying supply methods of nitrogen and irrigation on dynamics and distribution of soil nitrate nitrogen during maize（ Zay mays L.,cv. Gold northwestern 22） growth in Northwest China. Irrigation methods included alternate furrow irrigation（ AI）,fixed furrow irrigation（ FI） and conventional furrow irrigation（ CI）. Nitrogen supply methods included alternate nitrogen supply（ AN）,fixed nitrogen supply（ FN） and conventional nitrogen supply（ CN）,which were applied at each irrigation. Maize rows were established in west-east direction.Soil nitrate nitrogen content in south and north of the plant was measured in 0 ~ 100 cm soil depth（ 20 cm as an interval） before planting and at 6 collars,12 collars,tasseling,filling and maturity stages. The results showed that spatial-temporal distribution of soil nitrate nitrogen in south and north of the plant was influenced more by varying methods of nitrogen supply and irrigation compared with that under the plant,so did that in 0 ~ 40 cm soil depth compared with that in 40 ~ 100 cm. At filling stage,soil nitrate nitrogen of irrigated side was moved down to 60 ~ 100 cm soil depth for FI coupled with FN when nitrogen and water were applied within the same furrow,and that of non-water supply side was gathered in0 ~ 40 cm soil depth for FI coupled with FN when nitrogen and water were applied to different furrows.Compared with CI,AI reduced soil nitrate nitrogen under the plant in 40 ~ 80 cm soil depth by9. 9% ~ 14. 4% for different nitrogen supply methods. Compared with the other treatments,AI coupledwith CN or AN maintained soil nitrate nitrogen in 0 ~ 40 cm soil depth for a longer time during maize growth. Soil residual nitrate nitrogen in 0 ~ 100 cm soil depth at harvest was comparable between AI coupled with CN and AI coupled with AN,and the residual of them was reduced by 11. 7% ~ 27. 3%compared with those of the other treatments. Therefore, alternate furrow irrigation coupled with conventional or alternate nitrogen supply brought a relatively reasonable spatial-temporal distribution of soil nitrate nitrogen during maize growth,and lowered soil residual nitrate nitrogen at harvest.