本项目针对夏玉米种肥同播过程中存在的肥料投入量大、配比不当、面源污染重、利用率低等制约高产高效的突出问题，以土壤中可移动性差异显著的氮和磷两种元素为对象，通过降低氮磷肥料投入、优化施肥深度调控土壤养分的垂直分布，借助形态学和同位素示踪等技术手段，研究肥料减量20%条件下氮、磷及二交互作用对夏玉米根系组成；不同类型根系数量、长度与着生角度；不同类型根系上侧根起始分支位置、密度与长度；根系时空分布等构型指标的调控效应。借助动态离子流检测、分子生物学等技术分析根系对硝酸根和磷酸根离子吸收性能及吸收相关基因的表达量。从形态、生理、生化等多个层面揭示肥料减量适宜深度施用条件下氮、磷及二者交互作用对根系构型与生理功能的调控机理，探明调控高产夏玉米根系与土壤氮、磷时空耦合程度、提高肥料利用效率的可能技术途径，为协同提高产量与资源利用效率，促进夏玉米可持续增产增效提供理论与技术支撑。

No-tillage and seed-fertilizer simulcasting is one of the simplified and efficient cultivation technique of summer maize and widely been applied in China. However, in this cultivation technique, there are some outstanding problems like large amount of fertilizer input, improper fertilizer ratio, diffused pollution and low use efficiency, which seriously limited the high yield and high resource use efficiency of summer maize. Therefore, this project chooses two elements of nitrogen and phosphorus as key element, and they have significant differences of transferability in soil. We aimed study the regulation effect and mechanism of reduce nitrogen and phosphorus fertilizer input, optimize the depth of fertilization on vertical distribution of nutrients in the soil, maize root plasticity, especially root morphology and architecture, temporal and spatial distribution in soil and function. We will also study the interaction effect of nitrogen and phosphorus on root’s plastic and function. Morphology, physiological and biochemical and isotope tracer technologies will be combined to reveal its physiological mechanism of relieving internal competition of root system, and promotion of efficient economic utilization of photosynthetic assimilation in plants. Importantly, this study will provide the theoretical and technical support for the realization of the high spatial and temporal coupling of root and soil nutrient, and then promote of the synergistic improvement of production and resource utilization efficiency of summer maize.