宁夏引黄灌区耕地土壤有机质及养分质量分数变化趋势

Changing trend of organic matter and nutrient content in cultivated land of the Ningxia irrigation area of yellow river

通过对比1985年和2005年两次土壤调查结果，发现宁夏引黄灌区20年来耕地土壤有机质及养分质量分数趋于增加，速效磷质量分数明显增加，速效钾质量分数趋于降低．2005年灌区耕地土壤有机质质量分数平均为14．18g／kg，年增幅平均为0．4％．耕地土壤全氮质量分数趋于增加，2005年灌区耕地土壤全氮质量分数为0．945g／kg，增幅为0．9％．耕地土壤碱解氮质量分数变化不大，平均为54．48～65．77mg／kg．2005年灌区耕地土壤速效磷质量分数为34．86mg／kg，增幅为8．6％．耕地土壤速效钾质量分数趋于降低．2005年灌区耕地土壤速效钾质量分数为150．1mg／kg，平均年降幅为1．8％．灌区耕地土壤有机质及养分质量分数空间变异以速效磷质量分数变异系数最大，反映出灌区耕地磷肥施用量不均衡．从影响耕地土壤有机质及养分质量分数变化的各种因素方面，阐明了其变异趋势的原因，提出要大力推广测土配方施肥技术，积极开展以增施有机肥为中心沃土工程等培肥地力的对策．

The changing trend of organic matter and soil nutrient content of the cuttlvated kand of the Ningxia irrigation area of yellow river in 2005 were discussed, compared with the soil investigation result in 1985. The result showed that the organic matter content were gradually increased since 1985, the average organic matter content were reached to 14.18 g/kg in cultivated land of the Ningxia irrigation area of yellow river. The organic matter content was increased 0.4%0 per years. The total nitrogen content of the cultivated land were also increased, which were reach to 0. 945 g/kg in 2005. The proportion of the total nitrogen increased were 0.9 per years since 1985. The available nitrogen have not obviously increased trend, the average available nitrogen content were about 54. 48--65. 77 mg/kg in the cultivated land in 2005. The available phosphorus content has an obviously increased trend in the cultivated land, the proportion of the available phosphorus increased were 8.6 per years. The available potassium content of the cultivated land has also a decreased trend, which were 150.1 mg/kg in 2005. The available potassium content of the cultivated land were decreased the 1.8% per years. Spatial heterogeneity of organic matter and soil nutrient in the cultivated land of the Ningxia irrigation area of yellow river were also studied in this thesis, the reason of soil nutrient spatial heterogeneity and the effect factors of soil organic matter and the soil nutrient content in the cultivated land were also analyzed. So, we concluded that it is important to development the Formula fertilization technology, it is the most important countermeasure to vigorously develop the technology on increasing organic fertilizer to the farm.