不同水氮条件下灌溉方式对玉米干物质量和氮钾利用的影响

由于作物需水随生育期的变化,分根区交替灌溉(AI)的节水效果也会随生育期而发生变化,探明不同生育期分根区交替灌溉对玉米生长和水分养分利用的影响,以期为分根区交替灌溉的实施和充分发挥其节水节肥效果奠定理论基础。通过盆栽试验,在2种灌水水平(正常灌水和轻度缺水)和2种有机无机氮比例(100%无机氮和70%无机氮+30%有机氮)下,以常规灌溉(CI)为对照,分别研究苗期—灌浆初期、苗期—拔节期以及拔节期—抽雄期进行AI对玉米干物质量、氮钾含量和吸收量以及土壤碱解氮和速效钾含量的影响。结果表明,在轻度缺水和有机无机氮肥配施下,与CI相比,拔节期—抽雄期分根区交替灌溉玉米地上部和总干物质量分别增加29.6%和27.4%,地上部和总N吸收量增加50.7%和50.4%。与单施无机氮肥相比,有机无机氮肥配施会在不同程度上增加地上部和总N吸收量,但是一般降低土壤碱解氮和速效钾含量,这说明在轻度缺水和有机无机N肥配施下,拔节期—抽雄期进行分根区交替灌溉提高玉米总干物质量和N吸收量。

Effect of irrigation method on dry mass and nitrogen and potassium utilization of maize under different water and nitrogen conditions

Crop water requirement varies with the growth stage, so water-saving effect of alternate partial root zone irrigation (AI) also varies with the growth stage. Understanding the effect of alternate partial root-zone irrigation at different growth stages on maize growth and water and nutrient utilization can provide the theoretical foundation for the implement of alternate partial root zone irrigation and fully exerting its effect of saving water and fertilizer. Taking conventional irrigation (CI) as the control, this study has investigated the effects of AI respectively at seedling- early grain filling, seedling-jointing and jointing-tasselling stages on dry mass, nitrogen and potassium contents and uptakes of maize and available N and K contents in soil using a pot experiment under two irrigation levels (normal irrigation and mild water deficit) and two ratios of inorganic to organic N (100% inorganic N and 70% inorganic N + 30% organic N). Results indicate that under mild water deficit and combined application of organic and inorganic N fertilizer condition, AI at the jointing-tasselling stage increased shoot and total dry masses by 29.6% and 27.4%, and shoot and total N uptakes by 50.7% and 50.4%, respectively, if compared to CI. Combined application of organic and inorganic N increased shoot and total N uptakes to some extent, but generally reduced soil available N and K contents when compared to only inorganic N. Thus alternate partial root-zone irrigation at the jointing-tasselling stage could increase total dry mass and N uptakes under mild water deficit and combined application of organic and inorganic N fertilizer.