华北平原典型区土壤肥力低下区识别及限制因子分析

采用序贯高斯模拟方法对山东禹城市土壤质量指数的空间表征进行了评价,并深入分析了土壤肥力低下区的范围及其主要限制因子。结果表明,禹城市西南和中部土壤肥力质量指数较高,肥力质量较低的区域主要分布在该市北部、西北和东南三个区域。利用土壤肥力质量与产量的关系,确定禹城市土壤肥力低下的判定阈值为0.55,该市大部分区域土壤质量指数处于该阈值以上,仅在北部、西北和东南三个相对独立的区域共有2 494 hm2的耕地土壤肥力低下的风险较高。该市北部肥力低下区的主要限制因子是土壤质地和全磷含量,西北部主要受土壤盐化限制,而东南部的土壤肥力低下区则受土壤速效养分低、土壤盐化、质地较差以及土壤全氮含量不足等多个限制因子影响。

Identification of areas low in soil fertility and analysis of their limiting factors in the region typical of the North China Plain

The accurately spatial distribution prediction of soil fertility quality and the identification of soil fertility quality problem area are necessary to improve sustainable land use management. Base on the soil fertility quality data of total of 99 topsoil (0~20 cm) samples in Yucheng City, the sequential Gaussian simulation (SGS) were applied to perform a conditional stochastic simulation in this paper to quantitatively assess the uncertainty of spatial distribution prediction of soil fertility quality and identify the soil fertility problem area. Results show that the southwest and the central parts of the Yucheng City have the higher soil fertility quality than the north, northwest and the southeast parts. The relationship between soil fertility and crop yield show that 0.55 is the cutoff value to identify the problem area of soil fertility. Using this cutoff value and the spatial uncertainty assessment, 2494 ha land was been identified as the problem area. Furthermore, the mainly obstacle factors of the northern part of study area are soil texture and the soil total phosphorus content, the soil fertility quality in the northwestern part are affected by soil salt content and soil fertility quality in the southeastern part are controlled by soil availability nutrient, soil salt cont and soil total nitrogen content.