垄沟覆膜集雨系统垄宽和密度效应对玉米产量的影响

通过大田试验研究了垄沟覆膜集雨系统中，垄宽和密度效应对玉米产量和水分利用效率的影响。垄沟覆膜集雨系统有30、60 cm 2种垄宽，低、中、高3种玉米种植密度。结果表明，垄沟覆膜集雨能提高土壤含水率和土壤微生物量碳质量分数。随着玉米密度的增加，同一垄宽的垄沟集雨系统中，玉米株高和单株生物量逐渐下降，玉米单位面积生物量逐渐增加。降雨量较少的情况下，60 cm垄宽的垄沟覆膜集雨能显著提高玉米的叶绿素质量分数，但其在高密度条件下却显著降低玉米叶绿素质量分数。高密度条件下，30 cm垄宽的垄沟覆膜集雨处理，由于玉米种内竞争较激烈而导致有机物质向籽粒输入减少，从而引起产量降低。在所有的处理中，高密度、60 cm垄宽的垄沟覆膜集雨种植的玉米产量和水分利用效率最高。

Effects of ridge width and planting density on corn yields in rainwater-harvesting system with plastic film mulching on ridge

Field experiment was carried out to study effects of ridge width and planting density on corn yields and water use efficiency in a plastic film mulching on ridge for rainwater-harvesting system. The system was designed by two widths of ridges of 30 cm and 60 cm that had three planting densities of high, middle and low. The results showed that soil water content and microbial biomass carbon content were increasing in the system. Corn height and biomass per plant decreased gradually but biomass per unit area increased gradually in the system with the increase of corn density under the same wide ridges. The rainwater- harvesting system with the ridge width of 60 cm could significantly increase chlorophyll content during a period of less precipitation, but significantly decreased the chlorophyll content in high corn density. The rainwater-harvesting system with the 30 cm wide ridge would make grain yield decrease due to the decreasing proportion of organic matter allocation to grain caused by intensive intraspecific competition. The rainwater- harvesting system with the ridge width of 60 cm and the high planting density had the highest yields and water use efficiency among the treatments.