容重对红壤水平入渗及氯离子运移特性影响

Effect of bulk density on red loam horizontal infiltration and Cl^- transport characteristics

为了研究不同容重红壤KCl溶液的水平一维入渗和氯离子运移特性,进行了室内水平一维入渗试验,入渗溶液为摩尔浓度0.1 mol/L的KCl溶液,试验土壤为红壤,土壤容重设定为1.20,1.25,1.30,1.35,1.40 g/cm3等5个不同的水平,试验结束后对数据进行了理论分析.结果表明:容重对红壤土水分入渗和氯离子运移影响具有统计学意义,入渗率、累积入渗量和湿润锋随土壤容重的增大而减小;入渗结束后,各土层含水量和氯离子分布趋势基本相同,在相同入渗距离,红壤容重越大,氯离子含量越小,但相差不大;Philip入渗模型和Kostiakov入渗模型都能较好地反应不同红壤容重水平一维入渗的累积入渗量与时间的关系(R2>0.98),Philip模型和Kostiakov模型中反映入渗特性的系数S和K均随红壤容重的增大而减小,说明累积入渗量与红壤容重呈负相关关系.研究结果可为红壤地区农作物的灌溉施肥提供理论支撑.

In order to study the one-dimensional infiltration and Cl^-1 transport characteristics at diffe- rent bulk density of red loam, indoor horizontal one-dimensional infiltration experiment was carried out. The infiltration solution was the KCl solution whose concentration was 0. 1 moL/L,the experimental soil was red loam and the soil bulk density was set to five different levels of 1.20,1.25,1.30,1.35 and 1.40 g/cm^3. The theoretical analysis was done after experiment. The results show that bulk density affects significantly red loam water infiltration and Cl^-1- migration. Furthermore, infiltration rate, cumu- lative infihration volume and wetting front decreased with the increase of soil bulk density. After infil- tration, the content of Cl^-1 - in the soil had a negative correlation with soil bulk density. Philip infiltration model or Kostiakov infiltration model can accurately reflects the relationship between cumulative infil- tration and time of different bulk density red soil under one-dimensional infiltration condition （R^2 〉 0. 98）. The coefficient S and K of two models decrease with the increase of soil bulk density,it shows cumulative infiltration and red soil hulk density is negatively correlated. The results can provide theore- tical support for cotton irrigation and fertilization in red loam areas.