砒砂岩与沙复配土的水土保持效应研究

Soil and water conservation benefit of composite soil with feldspathic sandstone and sand

毛乌素沙地的水土流失严重,是黄河下游泥沙和北方沙尘暴风沙的主要起源地之一。本文以水土保持为目标,以砒砂岩与沙复配成土为研究对象,采用小区试验、模拟土柱试验和风洞试验方法,设置砒砂岩与沙的质量比例分别为1∶5(S_1)、1∶2(S_2)、1∶1(S_3)的处理,以S_s(全沙)、S_(ss)(全砒砂岩)为对照,研究复配土的保水、保肥、保土能力。结果表明:复配土中随着砒砂岩的增加,土壤粘粒、粉粒含量逐渐增加,沙粒含量逐渐减少;S_3处理的复配土,土壤大团聚体含量最高,呈现出随着含沙量的增加,土壤大团聚体减少的趋势;不同处理的土壤含水量S_3>S_2>S_1,砒砂岩与沙复配比例为1∶1时,土壤蓄水条件较好;砒砂岩与沙复配比例为1∶1时土壤保肥效益最好,其中硝态氮含量分别比S_s(全沙)、S_(ss)(全砒砂岩)高24.64%、43.10%;S_1、S_2、S_3处理与S_s、S_(ss)相比,风蚀量均显著减少89%以上。其中在7 m·s-1的风洞模拟风速下,S_1处理的复配土风蚀量最小。砒砂岩与沙复配可以提高保水、保肥及保土效益,复配比例为1∶1时,水土保持效益最佳。试验结果在土地复垦和土壤改良等方面具有重要参考意义。

The water and soil loss in the Mu Us Desert is serious and it is one of the main origins of sediments in the lower reaches of the Yellow River and sandstorms in the North.This paper aimed to evaluate the soil and water conservation and resource utilization technology of feldspathic sandstone and sand.Using field experiments to simulate soil column tests and wind tunnel test methods,the quality ratio of sandstone and sand is set to 1∶5(S_1),respectively.In the treatment of 1∶2(S_2)and 1∶1(S_3),using Ss(all sand)and Sss(full sandstone)as controls,the water retention,fertilizer retention,and soil conservation ability of the compound soil were studied.The results showed that:with the increase of feldspathic sandstone,the content of soilclay and silt gradually increased and the content of sand decreased gradually in the compound soil.The content of macroaggregates in the soil treated with S_3 was the highest,showing the highest content of soil aggregates.With the increase of sediment concentration,the tendency of large aggregates in soil decreases;soil moisture content of different treatments S_3>S_2>S_1,when the proportion of sandstone and sand mixed is 1∶1,soil water storage conditions are better;the benefit of soil fertility conservation was the best when the proportion of sandstone and sand was1∶1,and the nitrate nitrogen content was 24.64% and 43.10% higher than Ss(all sand)and Sss(all sandstone);compared with S_s and S_(ss),S_1,S_2 and S_3 treatments have significantly reduced wind erosion by more than 89%.Among them,under the simulated wind speed of wind tunnel of 7 m·s-1,the amount of wind erosion of the compound soil treated by S_1 is the smallest.The combination of sandstone and sandstone sandstone can improve water conservation,fertilizer retention and soil conservation benefits.When the compounding ratio is 1∶1,the benefits of soil and water conservation are the best.The test results have important reference significance in land reclamation and soil improvement.