西辽河平原灌区深松措施下磷肥下移提高春玉米磷效率的生理机制

Phosphorus content in root layer and the temporal and spatial distribution of root in the soil directly impact phosphorus absorption and utilization by spring maize, but their optimum matching relations and physiological mechanisms of phosphorus regulation are not clear. Based on the previous work, we found there were enrich accumulation of phosphorus in the surface but lack in the deep layer of soil caused by the plough pan due to shallow tillage with small power machinery over years. Subsioling could break plough pan, improve distributuion of phosphorus, and promote roots penetration in the soil, but lead to deterioration of spatial match of roots and phosphorus nutrients. In view of the above, we supposed a hypothesis that included a coupling of supply and demand of phosphorus in the time and space through downwards shifting phosphate, by which the phosphorus use efficiency can be improved in maize production.. We will ascertain phosphorus content, the temporal and spatial variations of root and their matching relations in root layer soil by field trials at multiple locations. Both PVC pole culture and field experiments were carried out to study the effect of downwards shifting phosphorus on root characteristics (morphological characteristics, physiological activity and temporal and spatial distribution), canopy biomass production (matter accumulation, physiological functions and yield formation) and phosphorus absorption and utilization (absorption feature, transshipment contribution and utilization efficiency), and to reveal physiological mechanisms of improving phosphorus use efficiency through downward shifting phosphate. Meanwhile, the research supplied a new way to manage phosphorus in root layer soil, and thus provided theoretical evidences and technical supports about low utilization and high use efficiency of phosphate fertilizer management for Xiliaohe Plain and similar areas in spring maize production.

根层磷素养分与根系的时空分布直接影响到春玉米对磷的吸收与利用，但其适宜的匹配关系与调控磷效率的生理机制尚不清楚。我们的前期工作发现，多年的小动力农机作业造成了土壤磷素养分表层富积而下层不足，深松打破了犁底层促进了春玉米的根系下扎，导致了根系与磷素养分的空间匹配性变差。据此提出通过磷肥下移实现磷素养分供需在时空上的耦合提高春玉米磷效率的科学假设。我们将通过多点田间试验，探明深松措施下根层土壤磷含量和根系特性的时空变化规律及二者间的匹配关系；通过大田栽培和PVC土柱栽培相结合的方法，探明磷肥下移对根系特性（形态特征、生理活性、时空分布）、冠层物质生产（物质积累、生理功能、产量形成）和磷吸收利用（吸收特征、转运贡献、利用效率）的影响，揭示磷肥下移提高春玉米磷效率的生理机制，为根层磷素养分调控提供新思路，为西辽河平原及其同类地区春玉米减磷增效提供理论指导和技术支撑。

摘要：以西辽河平原种植面积较大的郑单958和先玉335为供试品种，研究深松对春玉米根系特征、生理特性、干物质积累、产量及其构成、磷素养分吸收利用的影响；同时，采用大田栽培和PE土柱栽培相结合的方法，研究施磷深度和分层施磷对春玉米根系特性、冠层物质生产和磷素吸收、转运和利用效率的影响；在这些研究的基础上，进一步探讨深松措施下磷肥下移提高春玉米磷效率的生理机制。研究结果表明，深松促进春玉米根系特别是下层根系干质量的增加，增加根系纵深分布，春玉米根系重心下移，并保持较高的生理活性；同时，深松能促进春玉米干物质和磷的积累、转运，提高磷的收获指数、吸收效率和偏生产力，但不同玉米品种间存在显著的差异，郑单 958 产量和磷效率对深松更为敏感。在土柱栽培条件下，施磷深度12cm处理产量、磷积累量、磷肥偏生产力、磷吸收效率和利用效率均高于施磷深度6cm、18cm和24cm处理。大田栽培深松措施下磷肥下移至12cm，春玉米籽粒产量和磷素吸收效率、磷肥利用效率均显著高于其他处理（含常规施磷深度6cm），证明了深松措施下磷肥适度下移能够实现春玉米高产栽培减磷增效的目标。本研究结果可为西辽河平原及其同类地区春玉米生产减磷增效提供理论参考和技术支撑。