盐渍化节水灌区氮磷互作效应及土壤微生物学特征反馈机理研究

Hetao Irrigation Area is the agricultural production essential area in China.The chemical fertilization quantity increase every year, and the salinity irrigation area is now challenged with the sharp reducing of diverting irrigation water quantity from Yellow River forced by the new policy. The pollution of Farmland environment and the Yellow River water, soil salinity and water shortage will be the important factors to restrict the agricultural sustainable development. Developing research of N、P interaction effect and feedback mechanism of soil microbial properties under the water saving in salinization irrigation area is the requirement of promotion of modern agriculture and improvement of agricultural cleaner production level, and it is an important measure for irrigation area of ecological environment security and water security in the Yellow River. The research site is located at Hetao Irrigation Area of Inner Mongolia, Based on the field trials, the fertilizer utilization efficiency and fertilizer loss mechanism of wheat and corn interplant under the salt stress and water saving conditions will be studied. Based on the test, we can build the Nitrogen transformation migration model that based upon Vensim, simulate leaching losses of nitrogen on the salinization irrigation area, determine the nitrogen and phosphorus threshold value in the condition of minimum nitrogen leaching loss,ask the water-saving interplant crops of nitrogen and phosphorus fertilizer clean optimization model in salinization irrigation area, find out the feedback machanics of soil microbial characteristics on the different nitrogen and phosphorus interaction mechanism.The results will provide the scientific theory basis for the protection and control of the non-point contamination.

内蒙古河套灌区作为我国重要的农业精华地区，农业生产过程中化肥用量呈逐年加大趋势，同时，这个盐渍化灌区又面临着政策性引黄水量的锐减，农田环境和黄河水质污染、土壤盐渍化及缺水将是制约该地区农业可持续发展的重要因素。在盐渍化灌区节水条件下开展氮磷互作效应及土壤微生物学特征反馈机理的研究，是提高灌区农业清洁生产水平和推进现代农业的重要科技需求，也是灌区生态环境安全和黄河水质安全的重要举措。研究以内蒙古河套灌区为背景，以田间试验为支撑，揭示盐分胁迫及节水条件下套种作物的肥料利用效率及流失机理；在试验基础上，构建基于Vensim的氮素转化运移模型，模拟盐渍化灌区氮素的渗漏损失，确定最小氮素淋溶损失的施氮、磷阈值，提出盐渍化灌区节水型套种作物氮、磷配施清洁优化模式，揭示氮、磷配施条件下耕层土壤微生物学特征参数的反馈机理，研究成果将为制订灌区农业面源污染有效防治措施提供依据。

内蒙古河套灌区作为我国重要的农业精华地区，农业生产过程中化肥用量呈逐年加大趋势，同时，这个盐渍化灌区又面临着政策性引黄水量的锐减，农田环境和黄河水质污染、土壤盐渍化及缺水将是制约该地区农业可持续发展的重要因素。在盐渍化灌区节水条件下开展氮磷互作效应及土壤微生物学特征反馈机理的研究，是提高灌区农业清洁生产水平和推进现代农业的重要科技需求，也是保障灌区生态环境安全和黄河水质安全的重要举措。研究以内蒙古河套灌区为背景，以田间试验为支撑，揭示盐分胁迫及节水条件下套种作物的肥料利用效率及流失机理；在试验基础上，构建基于Vensim的氮素转化运移模型，模拟盐渍化灌区氮素的渗漏损失，揭示氮、磷配施条件下耕层土壤微生物学特征参数的反馈机理。研究结果发现中氮中磷处理（N2P2）能够较好的满足作物对氮、磷肥料的需求，提高作物对氮素的吸收、利用、转运，同时，降低作物收获后的氮素盈余，降低土壤中硝态氮残留量和农田硝态氮淋失量。利用Vensim模型建立的氮素模型包含了几乎所有的氮素迁移转化过程，从模拟结果看模型模拟数据与试验数据拟合较好，用Vensim模型建立的模型模拟小麦玉米氮素的淋溶渗漏损失具有一定的有效性。在施磷量适宜时提高施氮水平，土壤微生物含量和酶活性均呈现出先增加后降低的趋势，在N2水平时，土壤微生物含量和酶活性出现峰值且增加的效果最显著，当施氮量为N3水平时，土壤微生物含量和酶活性反而呈下降的趋势。综合氮磷互作效应和施氮对土壤微生物学特征参数的影响，优化施氮阈值为：167.67～192.20kg·hm-2、222.10～299.14kg·hm-2。为合理施用氮肥、提高肥料利用率、减轻农业面源污染及农业的可持续发展提供了参考依据。