黄土高原东南部旱作农田一年二熟种植模式水分效应初探--以杨凌为例

Study on effect of double-cropping system on moisture of dry farmland in the southeast Loess Plateau——A case study of Yangling

为了揭示"一年二熟"种植模式的农田土壤水分动态及耗水规律,试验设置了4个不同的"一年二熟"种植模式,测定分析了不同种植模式的土壤水分动态变化、水分满足率、作物耗水强度及作物产量等指标。结果显示:在黄土高原东南部年降雨量达640 mm左右的旱作农田,发展"一年二熟"种植能较好地利用夏闲期的水热资源,不同程度地提高了全年的生物产量、经济产量、水分利用效率,加强了农田物质循环。"冬小麦—大豆"、"冬小麦—玉米"两个种植模式的平均耗水强度仅比"冬小麦—夏闲"(对照)处理高0.07、0.1 mm/d,而"冬小麦—谷子"的耗水量等同于对照。经济效益以"冬小麦—玉米"为最好,土壤水分资源的持续利用性以"冬小麦—谷子"最好,一年二熟在取得显著经济效益的前提下具有可持续性;综合考虑该区的自然资状况,在旱作农田下最优的"一年两熟"种植模式为"冬小麦—玉米","冬小麦—大豆"。

In order to observe soil water dynamics and water consumption in different multiple cropping systems by regarding it as a whole, analysis was made of soil water dynamics, water satisfied rate, daily water consumption and yield of different treatments. The results showed that： planting two crops in a year under the condition of 640 mm annual mean rainfall in the Loess Plateau conduced to the substantial use of solar and water resources in summer fallow, the biomass yield, economical yield and water use efficiency was improved in different degrees, and the material cycle was enhanced. The daily water consumption of treatment Ⅲ and treatment Ⅳ were only higher by 0.07 mm/d and 0.1 mm/d compared with the contrast, treatment Ⅱ was equal to the contrast. The best economic returns of multiple cropping systems were ＂wheat--maize＂. The best sustainability of soil water is ＂wheat--foxtail millet＂. In the premise of significant economic benefits, multiple cropping systems can be sustainablly developed. The optimum multiple-cropping systems with efficient resources utilization and high economic benefits are ＂wheat--maize＂ and ＂wheat--soybean＂.