华北半干旱区农田土壤肥力变化及培肥管理对策——以山西忻府区为例

为了揭示华北半干旱区农田养分丰缺状况和演变规律，和指导培肥地力管理措施，以忻府区为例，采用1963年、1980年、2006年和2010年4次土壤肥力监测及农业统计数据和农户调查资料，研究4个主要土壤肥力指标（有机质、全氮、有效磷和速效钾）的变化程度，并分析忻府区农田土壤肥力演变趋势及原因，提出未来培肥管理的相应对策。结果表明，自1963年以来，全区土壤养分平均含量总体处于逐年下降的趋势，1980年基本处于最低水平，之后养分开始缓慢回升，从2006年以后养分增加速度加快，到2010年，有机质、全氮、有效磷和速效钾含量分别达到15.3、0.79、15.6、149 mg/kg。导致这种变化的主要农田管理原因是，投入的严重不足和种植模式改变使前期肥力出现下降，1980年后化肥施用量大幅增加和灌溉条件的改善促进土壤肥力的回升，而秸秆还田加快了2006年以后土壤肥力回升。实施精准配方施肥，推行秸秆还田，有机无机相结合的施肥制度，并实行保护性耕作措施、改善灌溉条件和扩大灌溉面积的综合管理是所在区域加快土壤培肥的有效措施。

Change in Farmland soil Fertility and Nutrient Management Strategy in the Semiarid Regions of North China——As a Case of Xinfu County of Shanxi Province

In order to reveal characteristics of soil nutrients and guiding the fertility maintaining practices in the farmland in semiarid regions, the trend and mechanism of change in main soil fertilities （organic matter, total nitrogen, available P and available K） in farmlands of Xinfu County, Shanxi Province was analyzed by using soil survey data for 1963, 1980, 2006 and 2010, from which a sustainable strategy for agricultural nutrient resource management was put forward. The results indicated that, a significant change in soil fertility for 1963 through 2010. Since 1963, whole area mean soil nutrient contents in the overall decreased significantly, down to the minimum level in 1980. And then, the nutrients began to raise slowly, higher speed after 2006. Serious shortage of inputs and change of cropping patterns lead to fertility decline in the former stage, while a dosage augment of chemical fertilizer and improving irrigation promoted soil fertility after 1980, and returning straw to field speeded up the recovery of soil fertility after 2006. By 2010, organic matter, total nitrogen, available phosphorus and available potassium content reached 15.3, 0.79, 15.6, 149 mg/kg, respectively. To further enhance the soil fertility, implementation of precision fertilization, combined the application of organic and inorganic fertilizers, increment of incorporated straw into the soil, and implement conservation tillage, improving irrigation and the expansion of irrigated area, should be the main regulation direction of agricultural management in the future in the area.