低山丘陵区土壤-景观模型的可移植性研究

The Study of Soil-Landscape Model Transportability at Hilly and Mountainous Area

为了分析在相似地形和成土环境中土壤-景观模型的可移植性,以西南丘陵山地区为研究对象,选取面积约2 km2的区域作为土壤-景观模型的建立区域,利用逐步线性回归方法建立该区的定量土壤-景观模型,并以此建模区域为缓冲中心,在研究区划分出4个不同的模型移植区域(分别记作A、B、C、D区)。结果表明,土壤-景观模型的预测结果在整体上具有较高的准确性;离建模区域越远,平均绝对误差(MEA)和均方根误差(RMSE)均有逐渐增大的趋势,说明随着距离的增大,预测精度降低;在4个区域中,相对误差(RE)都有一定比例大于20%,且距建模区域越远,相对误差(RE)大于20%的比例越大,相对误差(RE)小于10%的比例逐渐减小。

In soil science, the studies of quantitative soil-landscape models have become very active in recent years. However, transportability of these models to unsampled landscapes is still unknown. In this study, a 2 km2typical hilly study area in southwestern China was chosen as the origin spot. And the soil-landscape model in origin area was built by using multiple stepwise regression with the data of soil properties and terrain attributes. Based on the distance from the origin spot, the study area was divided into 4 regions（denoted A, B, C, D area）. All these 4regions which had similar terrain and soil environment were used to analyze the transportability of the soil-landscape model. The results showed that： soil-landscape model got predictions with high accuracy level in general. As the distance from origin spot increases, the mean absolute error（MEA） and root mean of squared error（RMSE） had shown a tendency to increase as well. These meant the accuracy of prediction was reduced with the distance. However, when the distance reached to a threshold the accuracy was no lower any more. In 4 regions A, B, C and D, there were proportions that the relative error（RE） was more than 20%. And the farther from origin area, the greater they became. Meanwhile the proportion that relative error（RE） was less than 10% decreased gradually.