上海市不同经营体制下的土壤养分变异特征分析

通过对上海两种经营体制的土壤速效养分含量及变异性分析,结果表明:整个上海地区土壤速效钾均处于较低于的水平,都在临界值附近,而土壤有效锌在分散经营条件下处于中低水平,而在规模经营条件下有富集的趋势。土壤的有效铜含量在两种经营条件下均较高;同不经营体制下的土壤养分变异非管理元素的变异系数差异不大,管理元素在分散经营条件下的土壤养分一般都高于规模经营;规模经营条件下地块内的变异一般都在30%以下,所以,在分散经营条件下实施土壤养分精准管理的迫切性要高于规模经营地区;规模经营体制下和分散经营体制下的土壤速效养分的半方差结构均可用指数模型来描述。大多数土壤速效养分的半方差结构明显,结构性方差占总方差的比例均在50%以上。但分散经营条件下的管理元素相关距均小在规模经营条件下。

Spatial Variability of Soil Nutrient in Different Management Systems in Shanghai

Soil available nutrient content and its spatial Variability in two types of farm management systems were analyzed. The result showed that soil available K level was low and close to critical level in entire Shanghai area. Soil available Zn content was at a modest low level in small scale farming system while was at a relatively high level in large scale farming system. Soil available Cu level was high both in two types of management systems. Spatial variability for the no-managed nutrients was not significant difference in two different types of management systems and spatial variability for the managed nutrients in small scale farming system was higher than in large scale farming system. Under large scale farming system, spatial variability for the managed nutrients was often lower than 30% in the same field. So site-specific nutrient management is more necessary in small scale farming system than in large scale farming system. Semi-variation structures of soil available nutrients could be described in exponent model both in types of farm management systems. The semi-variation structure for most soil available nutrients was obvious and the rate of structural variation accounted for more than 50% of the total variation. However, the managed nutrients in small scale farming system had smaller correlation distance than in large scale farming system.