渝东北紫色土饱和导水率传递函数研究

为研究渝东北紫色土理化性质在垂直空间上的分布情况以及对饱和导水率的影响,进而建立饱和导水率与各理化性质间的关系函数,推求饱和导水率的传递函数,选择渝东北开州区、云阳县等7个区县内45个紫色土典型田块为研究区域,运用Excel 2013和Matlab 2015b软件统计分析后,利用多元非线性回归法推求并验证了渝东北紫色土饱和导水率传递函数模型和模型参数。研究表明:①研究区土壤饱和导水率变化范围在0.16～195.68 cm/d,变化范围广,空间变异系数大,变异性较强;同一采样点深度越大,饱和导水率越小;②土壤饱和导水率与有机质含量有显著的指数函数关系,与饱和含水量有较强的二次函数关系,与土壤容重和土壤颗粒的相关性不大;③本次试验建立的土壤饱和导水率传递函数模型及模型系数检验合格,预测值与实际测算值误差较小,精度良好,可用于渝东北紫色土饱和导水率的预测工作。

Study on Pedotransfer Function of Saturated Hydraulic Conductivity of Purple Soil in Northeast Chongqing

Soil samples of different layers were collected from 45 typical fields of purple soil in the 7 districts and counties of northeast Chonqing, the physicochemical properties and saturated hydraulic conductivity (K_s) of the samples were measured, and the corresponding pedotransfer function of K_s were setup by using Microsoft Excel 2013 and Matlab 2015b software. The results showed: 1) K_s varied from 0.16 to 195.68 cm/d, indicating a wide range, a large spatial variation coefficient and a strong variability. K_sat decreased gradually with the increase of soil depth. 2) K_s had significant exponential correlation with SOM and significant quadratic correlation with saturated water content, but did not correlated with soil bulk density and particle composition. 3) The established multiple nonlinear regression models had high accuracy, and could predict well K_sat with high accuracies, thus could be used to predict K_s of purple soil in northeast Chongqing.