民勤湖区表层土壤养分的空间异质性

利用地统计学方法研究了民勤绿洲湖区表层土壤养分碱解氮、速效磷和速效钾的空间异质性.结果表明:绿洲、过渡带和荒漠三种景观下表层土壤中氮磷钾含量都呈现出“丰氮、富钾、贫磷”的特征；碱解氮与速效磷的变异系数在绿洲区最小,荒漠区最大,而速效钾在荒漠区最小,过渡带最大,但都属于中等变异；从绿洲到荒漠,碱解氮、速效磷呈U型分布特征,而速效钾为倒U型分布特征.碱解氮的最佳拟合模型为Exponential,速效磷为PentaspHerical,速效钾为Tetrasherical;氮和磷的富集区位于绿洲区,而速效钾在过渡带上出现富集中心.土壤的养分元素含量除了与成土母质的元素有关外,人类活动的影响也是非常重要的因素.

Spatial heterogeneity of surface soil nutrients in Minqin lake area

By using the methods of geostatistics, the spatial heterogeneity of available N, available P and available K in surface soils in M inqin lake area was studied. The results indicated that soil N and K were rich b ut soil P was poor over the three landscapes of oasis, desert and transitional b elt. The variation coefficient of soil available N and P was the smallest in oas is area and the biggest in desert area, while that of soil available K was the s mallest in desert area and the biggest in oasis desert transitional belt. Soil nutrients in the study area wholly exhibited moderate spatial variability. The s oil available N and P presented a U shaped distribution pattern, and the soil available K presented an inverse U shaped distribution pattern from oasis to de sert. Available N, P and K fitted well to Exponential model, PentaspHerical mode l and Tetrasherical model, respectively. The enriched zone of available N and P was located in oasis area, whereas that of available K was located in oasis-dese rt transitional belt. The soil nutrient contents were related not only to the el ements of parent rocks, but also to the impact of human activities.