黄土区不同地貌类型耕地土壤养分空间格局及驱动因素

Spatial Patterns and Driving Factors of Soil Nutrient Contents in Cultivated Lands Across Various Topographical Types in the Loess Plateau

[目的]了解黄土区不同地貌条件耕地土壤养分空间格局,揭示养分空间变化的驱动因素,可为区域农业精准管理及农田工程建设提供参考。[方法]基于陕西黄土区2020年耕地土壤养分数据,采用克里金插值揭示4种不同地貌耕地土壤养分空间格局,采用地理探测器模型探讨养分空间变化的驱动因素作用。[结果](1)长城沿线风沙滩区、陕北黄土丘陵沟壑区、渭北黄土台塬区和关中平原区有机质(SOM)含量均值分别为10.20,10.08,15.28,18.78 g/kg,全氮(TN)均值分别为0.63,0.66,0.98,1.19 g/kg,有效磷(AP)均值分别为12.99,13.10,16.97,27.24 mg/kg,速效钾(AK)均值分别为117.72,149.94,217.27,252.83 mg/kg,各养分空间格局总体呈现出“风沙滩—丘陵沟壑—台塬—平原”逐渐递增的趋势;(2)日照时长对陕西黄土区整体养分含量解释力最大,其次为年气温与化肥用量,风沙滩区养分分布受土壤容重影响最大,丘陵沟壑区、台塬区及平原区均受化肥用量影响最大,排名前列的因子交互作用对养分的解释力均强于其单因子作用。[结论]风沙滩区及丘陵沟壑区宜适当增加养分输入及提升土壤保肥能力,台塬区及平原区宜注重提高养分利用效率;在农田建设过程中,应根据不同地貌区环境特征因地制宜地进行人为活动。

[Objective] This study aims to comprehend the spatial distribution patterns of arable soil nutrients in various geomorphic conditions of the Loess Plateau,to unveil the driving factors behind these changes,and to provide the critical insights for precision management in the regional agriculture and the construction of agricultural projects.[Methods] Based on the 2020 soil nutrient data from the Loess Plateau in Shaanxi,the Kriging interpolation method was employed to analyze the spatial patterns of soil nutrients across four different geomorphic types.The driving factors behind these nutrient spatial variations was explored by using the geodetector model.[Results](1) In the Loess Plateau,spanning from the Great Wall′s sandy lands,through the hilly and gully regions of northern Shaanxi,the loess table lands in northern of Weihe River,to the Guanzhong Plain,the average contents of soil organic matter(SOM),total nitrogen(TN),available phosphorus(AP),and available potassium(AK) exhibited a gradual increasing trend.Specifically,the SOM content averaged 10.20,10.08,15.28,and 18.78 g/kg,respectively,across these regions.TN averaged 0.63,0.66,0.98,and 1.19 g/kg.AP level averaged 12.99,13.10,16.97,and 27.24 mg/kg,and AK averaged 117.72,149.94,217.27,and 252.83 mg/kg,respectively.This trend indicated a consistent increase from the sandy lands to the plains.(2) In the loess area of Shaanxi,the duration of sunshine had most significant factor influencing overall nutrient contents,followed by annual temperature and fertilizer use.The distribution of nutrients in the windy area was predominantly affected by soil bulk density,whereas in the hilly and gully areas,plateau areas,and plains,fertilizer use was the primary influencing factor.The interaction of various factors provided a more comprehensive explanatory of nutrient dynamics than individual factor alone.[Conclusion] To optimize soil health,it is advisable to increase nutrient input and enhance soil fertility retention in sandy areas and hilly and gully areas.In contrast,the focus should be on improving nutrient utilization efficiency for plateau and plain areas.Additionally,in the process of farmland,it is crucial to tailor human activities to suit the environmental characteristics and specific conditions of different geomorphic regions.