杭州市耕地土壤肥力状况及区域差异

Status and Spatial Variation of Some Fertility Indexes of Cultivated Soils in Hangzhou Region

为全面了解杭州市耕地土壤肥力状况及存在问题,为科学管理有限的耕地资源提供依据,利用近期（2007—2008年）获得的耕地地力调查测定数据,统计分析了杭州市耕地土壤pH值、有机质、全氮、有效磷和速效钾等重要肥力指标的特征及其空间差异。结果表明,杭州全市耕地主要由酸性（pH 4.5~5.5）、微酸性（pH 5.5~6.5）和微碱性（pH 7.5~8.5）土壤组成,强酸性和碱性土壤的比例较低。土壤有机质和全氮以中量水平为主,大部分土壤的有机质和全氮分别在20~40 g/kg和1~2 g/kg之间,但仍约有1/4（27.00%）和1/8（12.06%）的土壤有机质和全氮偏低。全市耕地土壤有效磷高低差异非常明显,缺磷与富磷土壤并存;土壤速效钾的变化也较大,且多数土壤钾素明显不足。除滨海平原土壤以微碱性和中性为主外,其他区域的土壤以酸性和微酸性为主;土壤酸度以丘陵区为最高,其次为河谷平原区,而水网平原区相对较低。土壤有机质和全氮平均含量以水网平原最高,其次为丘陵区和河谷平原区,滨海平原最低。土壤有效磷以丘陵区为最高,其次为河谷平原和滨海平原,水网平原的最低。土壤速效钾以水网平原最高,滨海平原最低,丘陵区和河谷平原居中。不同县（市、区）因地貌特征、土地利用方式及施肥水平等的差异,其土壤肥力指标也有较大的差异。杭州市耕地土壤肥力在空间上的高度变异性及氮磷钾养分之间的不均衡性要求进一步完善测土配方施肥工作。

In order to understand the status and defect of soil fertility of cultivated soils in the Hangzhou Region, pH value, organic matter, total N, available P and available K of the soils covering 8 counties of the region were investigated. The results showed that： most of the soils were acid （pH 4.5-5.5）, slightly acid （pH 5.5-6.5）, and slightly alkali （pH 7.5-8.5）, and proportions of soils with strong acid or strong alkali were lower. Contents of organic matter and total N of the soils were mainly classified as medium level, mostly ranging from 20 to 40 g/kg for organic matter, and 1-2 g/kg for total N. However, there were 27.00% and 12.06% of the soils, respectively, with low levels of organic matter and total N. Soil available P varied greatly among 8 counties, and soils with high available P and with low available P existed simultaneously in all of the eight counties. Also, soil available K varied spatially, most of the soils had low level of available K. All of fertility indexes of the cultivated soils varied greatly with landscape. Soil pH decreased in the sequence of coastal plain, plain with water network, valley plain, and hilly areas. The contents of soil organic matter and total N were higher in plain with water network and lower in coastal plain, and both valley plain and hilly areas had medium levels of soil organic matter and total N. Higher concentration of available P was found in the cultivated soils in hilly areas, and mean available P decreased in order of hilly areas, valley plain, coastalplain, and plain with water network. Mean soil available K decreased in sequence of plain with water network, valley plain, hilly areas, and coastal plain. Because of differences in landscape, land use, and fertilizer application rate, 8 counties had different levels of soil fertility. Great spatial variation of soil fertility indexes and imbalance of soil nutrients in the cultivated land of Hangzhou Region suggested that further implementation of technique for soil testing and formulated fertilization is still needed.