喷灌条件下玉米地土壤水分动态与水分利用效率

为了探索适宜于鄂尔多斯高原玉米的最佳喷灌定额和节水效果，在鄂尔多斯市赛乌素镇喷灌示范基地内进行了田间试验，研究了喷灌和管灌方式下玉米地土壤水分动态、玉米产量及其构成因子和水分利用效率（WUE）的变化。结果表明：喷灌区土壤含水率在玉米全生育期内变化幅度较小，20～60?cm土层的含水率略高于其他土层，管灌区变幅较大；喷灌水入渗速率明显低于管灌；喷灌灌溉定额主要通过影响单穗粒数和单位数量粒籽质量影响玉米粒籽产量，对玉米穗数也有一定影响，当喷灌灌溉定额大于4?965?m3/hm2时，喷灌与管灌产量无明显差异，灌溉定额5?430?m3/hm2时，喷灌WUE可提高到1.26?kg/m3，比管灌提高17.76%；耗水量70.40%～88.90%来自于灌溉，且随灌溉定额的增加，所占比例增加；试验地从播种到定苗期需补充灌溉，否则玉米穗数（株数）会显著降低。

Dynamic variations of soil moisture and water use efficiency of maize under sprinkler irrigation

In order to study irrigation quota of maize and water saving effect of sprinkler irrigation on Erdos Plateau, a large-scale field experiment was conducted in sprinkler irrigation base of maize in Saiwushu town of Erdos from May to October, 2009. Dynamic variations of soil moisture in maize field, maize yield and its components, water consumption and water use efficiency (WUE) under sprinkler and pipeline irrigation were tested and quantitatively analyzed. The results showed that the changed range of soil moisture in sprinkler treatment was less than that under pipeline irrigation throughout maize growth period. Soil moisture in 20-60cm layer was slightly higher than the other layers in sprinkler treatment. Water infiltration rate under sprinkler irrigation was lower than that under pipeline irrigation. Sprinkler irrigation quota affected kernel number per ear and seed weight per kernel, and thus maize yield, and slightly affected the ear number on stalk. Difference in yields of maize under sprinkler and pipeline irrigation was not significant when sprinkler irrigation quota was higher than 4965 m3/hm2. WUE was 1.26kg/m3 in sprinkler irrigation quota of 5430 m3/hm2 (17.76% higher than that of pipeline irrigation). The ratio of irrigation to water consumption was 70.40%-88.90%, and it increased with irrigation quota. Without well watered from sowing to seedling stage, numbers of ears on stalk was declined.