控释尿素配伍腐植酸对玉米耕层土壤氮素转化及根系养分吸收的调控机制研究

Improvement of the nitrogen use efficiency and yields crops is a hot issue following the development of modern agriculture. Previous studies had shown that crop nitrogen use efficiency and yield could be increased significantly by combined application of controlled-release urea (CRU) and humic acid (HA). Even when the nitrogen input was reduced by 20%, the treatment still keeps the similar yields. However, the regulatory mechanism of soil nitrogen transforming, maize root morphology and nutrient uptake efficiency by the application of CRU and HA are still unclear. The regulatory mechanism of HA for the nutrient transmembrane diffusion of CRU was investigated by an self-made thermostatic airtight device. Besides, the mechanism of slow-release nitrogen on the active functional groups of HA was studied by FTIR detection. Moreover, the effects of CRU combined with HA on the soil nitrogen supply during the critical growth period of maize were explored by 15N isotopic tracer technique. In addition, the superposition effect based on the interaction of CRU and HA for soil nitrification and denitrification process was reseached by the BaPS nitrogen cycle monitoring technology. Meanwhile, the metabolic pathway and key gene of nitrogen utilization were investigated via transcriptomics and metabolome analysis. In the end, the regulatory mechanisms of CRU combined with HA for soil nitrogen transform and maize root growth were finial clarified after above systematic research. The theoretical foundation will be provided for the development of HA based controlled release fertilizer, which have great scientific significance value for the efficient utilization of nitrogen fertilizer.

如何提高氮肥利用率，实现作物高产高效是现代农业发展的热点。前期研究证明控释尿素配施腐植酸可显著提高作物氮肥利用率和产量，减氮20%依然稳产。然而控释尿素与腐植酸耦合对土壤氮素转化的调控途径，及其对玉米根系形态和养分吸收效率的影响机制仍不清楚。项目通过自制恒温密闭装置，探讨腐植酸配伍对控释尿素养分跨膜扩散的调控机制；结合红外光谱技术，探索缓释氮对腐植酸活性官能团的影响机理。通过15N同位素示踪，探明控释尿素配伍腐植酸对玉米关键生育期土壤氮素供应的影响机制；结合BaPS氮循环监控技术，探讨其交互对土壤硝化、反硝化进程影响的叠加效应；通过代谢组学技术，研究根系分泌物中主要差异代谢物并绘制其调控关系；利用转录组学技术，比较玉米氮代谢与转运相关的差异关键基因，并整合于代谢通路中，为腐植酸增效控释肥的研发与推广应用提供理论依据，对于氮肥高效利用具有重要科学意义。

本项目按照研究计划顺利开展了各项研究工作，执行情况良好，取得了预期的研究成果。阐明了农作物秸秆、淀粉、蓖麻油改性制备聚氨酯膜材对控释尿素养分释放动力学特性的调控机制；揭示了腐植酸的官能团及分子量特性对于改性技术的响应，对土壤物化性质的综合影响及玉米生长、光合作用、激素和渗透系统的调节作用；阐明了缓释氮条件下土壤溶液中尿素浓度处于较低水平时腐植酸显著抑制土壤氮素硝化与反硝化进程的调控机制；明确了氮素缓释持续矿化土壤有机质改善作物根系形态和养分吸收效率的微生物驱动机制；发现两者配伍可调控作物苯丙氨酸、氧化磷酸化、半胱氨酸和蛋氨酸等碳氮代谢通路从而提高氮利用效率；在冬小麦-夏玉米轮作体系进行了长期定位研究，为腐植酸增效型缓控释肥料研发和高效应用提供依据，丰富了缓控释肥料减肥增效理论体系。依托项目发表高水平SCI论文13篇，其中，中科院SCI一区杂志收录9篇；本项目第一标注7篇，第二标注4篇，第三标注2篇；申请发明专利3件，其中授权专利1件；获得山东省科技进步一等奖1项、山东省教学成果一等奖1项（首位）；培养研究生11名；转化相关技术成果2项，获专利许可费用421万元，超额完成了项目任务。