风沙区雨养耕地水分与养分动态及其对作物产量的影响

风沙区由于林带的缺少,雨养耕地风蚀现象严重,就地起沙,形成了风蚀地以及风积地在短距离内交错分布的特点。通过对风沙区雨养耕地土壤水养状况的定位研究得出:没有防护林带保护的雨养耕地有3种类型,即风蚀地、积沙地、过渡地段。沿主害风方向,上风地段为风蚀沙地,下风地段为风积沙地。风蚀沙地水分状况最好,风积沙地最差;表层土壤(0~20cm)养分状况比下层(20~60cm)差,风积沙地肥力最低,过渡地段最好。沙区雨养耕地特点明显,一年中土壤含水率变幅比降水量小得多,水养同步作物生产力水平高;农作物产量与土壤中全N、全P、全K含量关系不密切,与土壤表层有机质、有效P、K含量及下层有效N的含量呈明显的正相关。

Dynamics of Water and Nutrition and Their Impact on Crop Production on Dry Farmland in Sandy Area

Studies on water and nutrition dynamics of dry farmland were carried out in fixed positions in Sands area. There were 3 types of dry farmland in areas without shelterbelts, namely wind-eroded land(on the wind ward),wind-accumulated sand(on the leeward)and the transitional part. Wind-eroded land was the best and, wind-accumulated sand worst in moisture condition. The top soil (0~20cm) was better than the lower part (20~60 cm) in nutrition. Soil fertility was the poorest in wind- accumulated sand, and best in the transitional part. The dry farmland in sandy area had clear characteristics. The fluctuation soil moisture was smaller than that of rainfall in the year. Crops with synchronous needs for water and nutrition were of high production. The output was not greatly influenced by total N, P or K but in close correlation with organic matter, available P and K in top soil and available N in lower part.