苹果主产区土壤养分空间分布特征及其影响因素——以陕西省礼泉县为例

客观、定量化分析土壤养分空间异质性及其影响因素,可为作物精准施肥提供科学依据。本研究以陕西省礼泉县苹果产区为研究区,基于“S”形的样点布设法采集果园0~40 cm土层的土壤样品,运用地统计学和GIS研究了土壤有机质、碱解氮、速效钾和有效磷4种养分的预测精度,并通过交叉验证和相对预测误差确定最优预测模型,绘制果园土壤养分空间分布图,综合分析土壤养分空间分布特征,及结合相关性分析和多元线性回归分析,探讨土壤养分的影响因素及其权重。结果表明:1在最佳变异函数理论模型下,普通克里格法对果区土壤碱解氮的预测精度高,协同克里格对其他3种养分的预测精度高。2土壤有机质的空间分布格局是由骏马-阡东和建陵-昭陵一带向中部递减;赵镇至史德镇的东部为碱解氮的高值区,分别向东、北和西南递减;速效钾的高值区主要分布在研究区南部,北部大多数地区钾含量偏低;有效磷的高值区分布在烽火和骏马镇、石潭-昭陵镇一线。3有机质与地形因子具有显著相关性,碱解氮受NDVI、土壤类型和地形因子的影响,速效钾与当地坡度、坡向具有显著相关性,但有效磷与三大类因子的相关性不显著。

Spatial Distribution of Soil Nutrients and Their Influential Factors in Apple Production Area-A Case Study of Liquan County, Shaanxi Province

Theobjective and quantitative analysis of spatial heterogeneity of soil nutrients and their influential factors can provide scientific basis for precision fertilization. Apple production area at Liquan County, Shaanxi Province was selected as the research area, soil samples at 0–40 cm depth were collected by the “S” shape sampling method, the mapping accuracies of soil nutrients including organic matter, alkali hydrolysable N, available K and available P were studied by geostatistics and GIS. The optimal prediction models were determined by cross-validation and relative tolerance, and spatial distribution maps of soil nutrients were drawn, the spatial distribution characteristics of soil nutrients were comprehensively analyzed. Moreover, influential factors of soil nutrients and their weights were decided by Pearson correlation and multiple regression analysis. The results showed that: 1) Under the optimal variogram model, the interpolation accuracy of Cokriging were better to predicate organic matter, available K and available P compared by Ordinary Kriging, while, Ordinary Kriging was better to predicate alkali hydrolysable N. 2) Soil organic matter showed a decrease trend from Junma Town-Qiandong Town, Jianling and Zhaoling Town to the middle part area; the high value area of hydrolysable N was from Zhao Town to the east of Shide Town, decreasing toward the east, north and southwest respectively; the high value area of available K was located in the south of the studying area; The high value area of available P was located among Fenghuo and Junma Town, Shitan-Zhaoling Town. 3) Soil organic matter and terrain factors were significantly correlated. Alkali hydrolysable N was affected by NDVI, soil types and terrain factors. Available K content was significantly correlated with slope and aspect, however, no significant correlation was found for available P.