黄河中游旱坡地枣园集水保水的效果

Water-collecting and Water-maintaining Effect of Arid Hillside Jujube Gardens in the Middle Area of Yellow River

晋西黄土区枣树生长前期 (4 6月份 )降雨量少是限制枣树生长发育的主要气候因子 ,在没有地下水的情况下 ,集水栽培是解决干旱问题的惟一有效措施。降水是黄土区产生地表径流的惟一来源 ,降水量、降水强度及降水历时是影响坡面径流过程和径流量的重要因子。人工模拟径流蓄集试验表明 ,当径流集蓄至 40 80mm时 ,增墒持续时间就能维持 30d左右 ;当径流集蓄超过 80mm后 ,增墒持续时间能够稳定在 45d左右。一次天然降雨 15mm ,集水枣园土壤水分含量能够维持 10d左右的增墒效果。 15mm <降雨量 <40mm ,集水枣园土壤增墒时间约在 10 30d之间。生长期内 (4 10月份 )降雨量达 30 0mm时 ,集水枣园水平沟集蓄效果开始显著 ,比对照平均提高土壤水分含量 1.30 %左右 ;低于 30 0mm时 ,尽管个别月份差异显著 ,但整个生育期计算 ,集水枣园集流增墒效果不显著。当生长期降雨量超过 40 0mm时 ,坡地枣园土壤水分含量比对照提高 1.7% 1.8%。覆盖能提高土壤水分含量 1%左右 ,但主要体现在降雨月份上 ,在非降雨月份或少降雨月份覆盖效果不显著。生长期松土能提高集水枣园土壤水分含量 0 .91% ,松土效果与降雨量有着密切的关系 。

The less rainfall during the first part of growth phase (April to June) in loess hills west Shanxi is the growth-limiting major climatic factor of jujube tree, under no ground water-using, water-collecting culture is the only one effective measure to control arid, precipitation in loess hills is the only resources which can lead to runoff, amount of precipitation, rainfall intensity and rainfall duration are importance factors which affect the runoff course at slope and the amount of runoff. Artificial stimulated test of runoff collecting shows when the accumulation deep of runoff reached 40 to 80 mm, the duration of the moisture preserving of the soil can keep about 30 days; when the accumulation deep was over 80 mm, the duration of the moisture preserving keeps steady about 45 days. There was 10 days effect of moisture-preserving in water-collecting jujube garden at a deep of 15 mm rainfall each time, when the amount of one precipitation is over 15 mm, and less than 40 mm, the duration of moisture preserving is between 10 to 30 days. In the whole growth phase(April to October), when the accumulative amount of precipitation reached 300 mm,the accumulation effect in level ditch of water-collecting garden began to be remarkable, the moisture content of the soil increased by 1.3% over the check; when the amount of precipitation was less than 300 mm, although there was a remarkable difference in the individual month, the moisture-preserving effect was not remarkable by the whole growth phase calculation in the water collecting jujube garden; when the amount of precipitation was over 400 mm, the soil water content of the slope garden increased by 1.7% to 1.8%. Grass covering raised the moisture of the soil nearly by 1%, which most reflected the month of precipitation, there was no difference of grass covering in the non-rainfall or less rainfall month. The soil-loosening in the growth phase can raise the moisture content by 0.91% in water-collecting garden, the effect of the loosening maintained close ties with precipitation, the difference was more obvious in the rainfall months.