黄土沟坡刺槐林地土壤水分垂直变化的数学模型

A Model Used to Describe Vertical Change of Soil Moisture of Robinia pseudoacacia Plantations Growing in the Loess Gully Slope

2004,2005年4—10月,在位于黄土高原半湿润水分生态区的陕西省长武县,采用中子仪对刺槐人工林土壤水分垂直变化进行监测,运用隔室模型和2004年的实测数据建立降水在土壤中的入渗平衡模型:WC=a(e-kh-1)+c(1-e-k1h)+f,其中a>0,c>0,f>0,k1>k>0,k1和k分别为土壤入渗水的吸附速率和衰减速度。k,k1在特定取值条件下,模型可表达黄土高原刺槐林下不同的土壤水分生态环境。采用2005年5月实测数据对模型的拟合验证结果表明:拟合优度R2符合统计学要求,能很好地反映刺槐人工林地土壤水分垂直变化特征。

Soil moisture plays an important role for forestry in the Loess Plateau.Using neutron probe,the vertical changes of soil moisture of Robinia pseudoacacia plantations grown in the semi-humid region were measured during April to October in 2004 and 2005.A compartment model and the data of the soil moisture measured in 2004 were used to set up a balance model with absorption chamber of rainfall infiltration into the soil：WC=a（e-kh-1）＋c（1-e k_1h）＋WC_0,if a〉0,c〉0,k_1〉k〉0.k_1 and k is the soil absorption rate and loss rate of rain water into soil the parameters under specific conditions reveal the different ecological environment of soil moisture of Robinia pseudoacacia plantations grown in the Loess Plateau.The model was tested and verified by using the survey data in May 2005.The result showed that the goodness of fit answered for need of statistics,and the model was able to well reflect the characters of vertical changes of the soil moisture.