微地形土壤养分空间变异特征及养分管理研究

选取安徽省郑蒲港新区作为研究区域,运用地理信息系统与地统计学相结合的方法,选取土壤有机质、p H、全氮、碱解氮、有效磷、速效钾作为研究对象,选择不同的插值模型,并分析了各土壤要素的空间变异特征。结果表明,受到土地平整和施肥等人为因素影响,地形因子(高程、坡度)对土壤养分的影响程度较小,研究区河流隔开采样数据出现空间不连续,采用区域分块插值的核平滑方法插值模型最为稳定,更加符合研究区实际情况,不会出现为满足假设条件而出现系数为负的插值方程。研究区5种土壤元素均呈现南北低中间高的趋势,土壤速效钾和有效磷的变异系数较高,碱解氮和有机质变异性较弱,p H变异性最弱。占研究区90%以上的土壤4种养分元素均土壤有机质含量均处在中上水平以上,只有占研究区面积的19.66%和72.30%的碱解氮,分别处在中上、中下水平,研究区面积的61.6%和35.67%的p H分别处于酸和弱酸级水平。

Spatial variability of soil nutrients and nutrient management in micro-topography

In this research, we chose different interpolation models to analyze the spatial variability of the soil elements in Chengpo port district of Anhui Province by analyzing soil organic matter, pH, total nitrogen, alkali nitrogen, available phosphorus and available potassium using Geostatistics method combined with GIS. The results showed that the topography (altitude and slope) exerted a little effect on soil nutrients due to activities including levelling the land and fertilizing. We observed that the data of river segregation samples remained spatially discontinuous, while the interpolation model by applying of kernel smoothing method in regional segregation interpolation kept the most stable, which corresponded to the realistic situation in the research region, avoiding a minus coefficient interpolation equation just for meeting the assumed conditions. All the five elements in the soil showed a trend of lower in South and North, and higher in the middle. Meanwhile, the variation coefficient of soil available potassium and phosphorus was high, while the variability of alkali-hydrolyzed nitrogen and organic matter was weak and pH was the weakest. The soil nutrients accounted for more than 90% of the study area were all above the middle and upper levels of soil organic matter content. Only 19.66% and 72.30% of alkali nitrogen in the soil of the study area were in the upper and lower levels. At the same time, the soil pH value of 61.6% of the study area was at the acid level, while the soil pH of 35.67% of the study area was at a weak acid level.