黄土丘陵沟壑区竹节式聚水沟聚水改土效应研究

Effects of Bamboo Knot-shaped Ditches on Rainwater Harvesting and Soil Structure Amelioration in the Hilly Loess Region of China

试验以水平阶地为对照,于7-9月在典型黄土丘陵沟壑区陕西省米脂县测定了竹节式聚水沟中间、上侧和下侧的土壤水分,并于4月初和9月末测定了聚水沟样地的土壤容重。结果表明:7-9月,各时期聚水沟整体土壤水分均高于水平阶地且差异均达到极显著性水平(p<0.01),200cm土层内聚水沟的储水量比水平阶地最高增加了53.54mm,增长率为29.5%;各时期聚水沟不同位置上土壤水分含量表现为沟中间>上侧>下侧,且中间与上、下侧土壤水分差异各时期均达到极显著性水平,上侧土壤水分变化幅度较下侧小;各时期聚水沟整体土壤水分含量表现为0～40cm土层最高,且从7月30日后呈不断下降趋势,>40～100cm土层次之,各时期变化幅度较小,>100～200cm土层最低,但呈不断增长趋势;沟内填充材料可以显著降低沟底10cm以内土层的土壤容重,增大总孔隙度(p<0.05)。竹节式聚水沟较水平阶地更能增加土壤水分含量,缓解浅层土壤干层形成,同时也具有改良土壤结构的作用,作为黄土丘陵沟壑区集聚水、保墒、改土于一体的新技术具有较好的推广应用价值。

Bamboo knot-shaped water harvesting ditches （BWHD） between the rows of jujube trees across the slope were built up. The ditches were filled with crushed biological materials to retain the rainfall. The soil moisture content of BWHDs at three sampling positions （top, middle, and the bottom） between July and September were measured, while the level bench terrace was used as the control. The soil bulk density （BD） and soil porosity （P） before and after constructing the ditches were also measured. The mean overall moisture content of BWHD was higher than that of the control throughout the observation period,and the difference between BWHD and the control was highly significant （p〈0.01）. BWHD significantly （p〈0.05） enhanced the soil water storage in 0 200 cm profile compared with the control with the maximum difference of 53. 54 mm in September （29. 5% higher）. The mean BWHD soil moisture contents of the three sampling positions were in the order of middle〉top2〉bottom. The difference between the middle po- sition and the top or bottom was highly significant （p〈0.01）. A comparison of the different layers showed that the overall soil moisture content was the highest in the 0-40 cm BWHD layer, although there was a de creasing trend from the end of July until the end of September. The 〉40-100 cm layer was higher than the 〉100-200 cm layer and it was relatively stable throughout the observation period. The 〉100-200 cm layer was the lowest,although there was an increasing trend. BWHD significantly ameliorated the physical prop- erties of 10 cm bottom soil layer by reducing the BD and increasing the P （p〈0.05）. Therefore,BWHD improved the soil moisture level and reduced soil desiccation in the 0 -200 cm soil layers compared with the control, and they had a better soil structure ameliorative function. BHWD could have widespread value as a new a pplication that could promote water harvesting, moisture conservation,and soil structure amelioration Hilly Loess Region of China.