水稻生产改为蔬菜或葡萄栽培对土壤养分的影响研究——以浙江富阳为例

Responses of Soil Nutrients to Land Use Changes from Rice Production to Vegetable Cultivation or Viticulture:A Case Study in Fuyang City, Zhejiang Province

以浙江杭州郊区为例,研究了土地利用方式变化对土壤养分的影响,以期对土地利用方式的选择提供借鉴。选取当地3种典型的土地利用方式变化类型,调查由传统水稻生产改为种植高经济收益的芦笋、葡萄或芥菜后不同年限对土壤养分变化的影响。结果表明,水稻田改种芦笋后,除铵态氮以外,土壤表层中的其他养分(有机碳、全氮、全磷、全钾、硝态氮、有效磷、速效钾)浓度均显著提高(P<0.05);全氮、全钾以及硝态氮的增幅延续到剖面深层。其他两种类型的土地利用方式变化也有相似规律,其中有效态养分增幅更为明显。土地利用方式变化对养分分布也有一定的影响,水稻田改种芦笋后全氮和全钾的浓度增加最为显著,而改种葡萄后变化最大的养分是速效钾,改种芥菜后土壤硝态氮上升更显著。因此,水稻田转变成种植其他经济作物会引起土壤表层乃至剖面深层养分浓度的增加,可能造成农业面源污染,易引起养分流失和导致水体富营养化。

Changes in land use may alter soil microbial, chemical and physical properties, thus influencing soil nutrients. Soil nutrient changes were investigated after changing paddy rice to asparagus production, to vineyards, or to field mustard cultivation in Fuyang city, Zhejiang province. Changing from paddy rice to asparagus production increased total organic C, total N, total P, total K, NO^-N, Bray-P, and NH4OAc-K） in surface soils（P〈0.05）, with an exception of NH4＋-N. Total N, total K, and NO^-N were also found to increase in sub- surface soil layer. Similar nutrient changes were observed in other two types of land use changes, but with greater changes found in ex- tractable than in total nutrients. Nutrient responses to land use changes were different among different use types. The greatest increases in total N and total K was found in asparagus production, NH4OAc extractable K in viticulture and NO3--N in field mustard. The results suggest that land use changes from paddy rice to cash crops might cause agricultural pollution via ＇nutrient leaching, and suitable planning is neces- sary to maintain agricultural sustainability.