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本研究以黄土高原沟壑区农田为背景,对当地的肥料投入和土壤养分进行长期定位监测,利用10余年的监测资料,分析地形与施肥对土壤养分和作物产量的不同影响,掌握坡改梯和塬面在经过长期施肥后其土壤养分的变化趋势,为当地农田的有效管理提供理论依据。本研究设置三大试验监测区,分别是梯田监测区(TL)、塬面监测区(YL)和农民地监测区(NM),各个监测区之间构成地形与施肥之间的不同因素对比。研究结果表明,长期施肥有效地提升了各个监测区的土壤养分水平。与试验前相比,塬面、农民地和梯田监测区的土壤有机质分别提升了5%、5%、24%;全氮提升了1.8%、6.5%、14%;速效氮提升了2%、12%、30.8%;长期施肥后塬面土壤有效磷降低,而梯田和农民地提升20%~30%左右;塬面和农民地土壤速效钾提升幅度在20%~31%之间,梯田出现降低。梯田监测区初始养分含量较低,但长期施肥能够显著改善其养分状况,这说明该地区坡改梯工程能够实现对当地土壤的有效利用及改良。在黄土高原沟壑区,作物产量受生育期降水量及其分配、积温条件和肥力水平的影响,气候因素的影响较为显著。
Based on the farmland in the gully area of the Loess Plateau, the long-term local monitoring of fertilizer inputs and soil nutrients was conducted. Based on more than 10 years of monitoring data, the different effects of topography and fertilization on soil nutrients and crop yield were analyzed. The change of soil nutrients in the plateau after long-term fertilization provides the theoretical basis for the effective management of the local farmland. Three monitoring zones are set up in this study, which are terrace monitoring area (TL), plateau monitoring area (YL) and peasant land monitoring area (NM) respectively. Comparisons of different factors between topography and fertilization are made in each monitoring area. The results showed that long-term fertilization effectively raised the soil nutrient level in each monitoring area. Compared with the pre-experiment, the soil organic matter in the plateau, peasant land and terrace monitoring area increased by 5%, 5% and 24% respectively; the total nitrogen increased by 1.8%, 6.5% and 14%; the available nitrogen increased by 2% 12%, 30.8%. After long-term fertilization, the soil available phosphorus decreased, while the number of terrace and peasants increased by 20% -30%. The increase of available potassium in the plateau and peasant land ranged from 20% to 31% reduce. The initial nutrient content of the terraced monitoring area is low, but the long-term fertilization can significantly improve the nutrient status, which shows that the slope to the ladder project in the region can effectively use and improve the local soil. In the gully area of the Loess Plateau, the crop yield is affected by the amount of precipitation and its distribution during the growing period, the accumulated temperature conditions and the fertility level, and the climatic factors have significant effects.