黄土区村级农田土壤养分空间变异特征研究

本研究选择黄土高原地区陕西省新集村为研究对象。在219hm2耕地上用网格法采集364个表层(0~20 cm)土壤,研究了该村土壤pH,有机质和速效养分(N,P,K,Ca,Mg,S)空间变异性。结果表明:该村98.9%耕地缺N,缺K,缺P比例占11.5%和4.4%。地统计学分析结果表明:土壤有机质、有效N、P、K、Mg、Ca、S具有中等的空间相关性,空间变异程度依次为:OM>P>Ca>K>Mg>N>S,土壤pH的空间相关性很弱。有机质、有效N、S最大相关距离大,达到1853m,pH值最小,为148m,K、Ca、P、Mg最大相关距离分别为717m、720m、1032m和1344m。施肥是导致该村土壤养分空间变异性的主要原因。基于土壤养分状况和空间分布特征,目前仅需要考虑对该村土壤K,P进行分区管理。

Spatial Variability of Soil Nutrients in Farmland of Loess Plteau

Total 364 top-layer(0-20cm) soil samples were taken in 70 m grid(cropping fields),50 m grid(fruit orchard),and 30m(greenhouse vegetable) from 219 ha~(-1) of cultivated land in Xinji village of Shanxi Province to investigate spatial variability of soil pH,OM,and nutrients(available N,P, K,Ga,Mg,S).Results indicated that soil N was widely deficient in the study area,11.5% and 4.4% of all samples were K and P deficient on the basis of assessment standard of SAI,corresponding value was 98.9% for N.Geostatistical methods was used and found the order of spatial heterogeneity was: OM>P>Ca >K>Mg >N >S.OM,N and S had the longest correlation range(1853m) and pH had the shortest(148m),whereas K,Ca,P and Mg had intermediate spatial correlation ranges.Spatial variability of soil nutrients could be contributed to the unbalance fertilization in this area.Based on the present situation and spatial distribution characteristics of soil nutrients,the key elements in nutrient management are K and P in the study village.