宁夏半干旱偏旱区旱地引进苜蓿品种适应性及生态耗水状况

2003-2005年对引进的15个苜蓿品种在旱地进行比较试验.结果表明,在干旱少雨的条件下,不同品种生长速度和地上生物产量不同,水分生产效率和耗水强度各有差异.第二年生长期耗水强度17.4～22.95 m3/(hm2·d),其中当年第一茬占全年65%～71%.第二年以后土壤水分出现亏缺状态,0～2 m土壤水分亏缺60.9～123.5 mm,平均87.8 mm,生产年度(包括非生长季节)同层土壤水分亏缺值高达121.9～165.5 mm,平均143.1 mm,生产年度土壤缺水系数为0.454～0.607.根据品种各综合性状指标生态适应性分析,对引进品种进行了种植区域界定,并按土壤水分逐年亏缺量下限频率(P=70%)推算,半干旱偏旱区旱地苜蓿适应当地多年降水资源的效益型生长年限不超过5年就需进行粮草轮作.

The Adaptability of the Import Alfalfa Varieties and Status of Ecological Water Consumption in the Semiarid and Liable to Droughts Areas of Ningxia

Comparative experiment on the adaptability of 15 import alfalfa varieties in dryland between 2003-2005 were studied. The results showed that there were significant differences in growth speed, shoot biomass,water consumption rate and water use efficiency among different alfalfa varieties in drought condition. Water consumption rate of growth period in the second year was 1.16-1.53 m³/(hm²·d),and water consumption rate of the first harvest account for 65%-71% of that in the same year.Soil water deficit appeared since the second year,soil water deficit was 60.9-123.5 mm amo ng 0-2 m soil depth,and the average value w as 87.8 mm. Soil water deficit of the same soil depth reached 121.9-165.5 mm in production year (including beyond the growing season),the average value was 143.1 mm,and soil water deficit efficiency of production year was 0.454-0.607.According the analysis of ecological adaptability and the lower frequency of soil water deficit(P=70%)year after year,in the semiarid areas and semiarid areas liable to droughts,the benefit growth period not exceeded than 5 year for adapted precipitation resources of the region,and required carried through grass-crop rotation.