In 2002,601 soil samples collected from sites extensively scattered over 100,000 hm2 of farmlands in 12 villages and towns of Jingchang City,Gansu Province were analyzed with results showing that the average content of soil organic matter in those soil was 15.1g/kg,and a large proportion of the farmlands was low or medium;and the proportion of the farmlands low in soil organic matter was growing while the one that was medium was shrinking.On the other hand,the average content of alkalytic nitrogen in those farmlands was 38 mg/kg,and farmlands deficient or fairly deficient in alkalytic nitrogen accounted for the most part of the farmlands.And the former was expanding and the latter reducing.The average content of available P in those farmlands was 20.9 mg/kg,showing an obvious increase.Most of the farmlands were high or medium in available P content and only a small portion was still low.The average content of available K in those farmlands was 158 mg/kg,showing an obvious drop.Most of the farmlands remained high or medium.The acreage of the farmland medium in soil available K was growing by a large margin.
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杨炳成.金昌市土壤养分现状与施肥建议[J].土壤,2006,38(2):228-231. YANG Bing-cheng. Soil Nutrients in Farmlands of Jinchang City and Fertilization Recommendations[J]. Soils,2006,38(2):228-231