间作水分高效利用的种间竞争互补机理

Interspecific competition and complementarity are leading factors influencing intercrops water use, while studies on synergistic effects of competition and complementarity in intercropping systems were limited. In this project,field experiments will be carried out under different root partitioning patterns,plant ratio and densities, as well as irrigation patterns in typical cereal/cereal,cereal/ legume intercropping and their corresponding sole crops. The purpose of the research as following: (1) To determine the tempo-spatial dynamics of dry matter accumulation allocation and irrigation water productivity, study compensation effects on water use in intercropped maize during post-harvest period of intercropped cereal(legume) crops in intercropping systems, and clarify the correlation between water use efficiency(WUE) of crops and interspecific interaction. (2)To investigate tempo-spatial dynamics of soil moisture, water potential, and available soil water, analysing the relationships among soil water movements within inter-specific competition/complementarity, in expectation to provide theoretical basis for optimizing interspecific competition and complementarity under irrigation regulations.(3)To evaluate the effects of different treatments on crop photosynthesis, transpiration, stomatal conductance, leaf area index and plant height, to reveal the complementary mechanism of inter-specific interaction with respect to hydro-physic-ecological viability.(4)To explore the correlations between root-shoot equilibrium and tempo-spatial distribution of root, as well as water use characteristics and inter-specific competition/complementarity, to elucidate how the root-shoot equilibrium works on improving water use efficiency via the synergistic effects of inter-specific competition and complementarity. Integration the main results under different research scale, construction academic basis for enhancing water use efficiency of intercropping through regulating interspecific interactions. Those findings from this project strengthen and deepen the theories on inter-specific interaction in intercropping systems, also provide essential basis for development and extension of intercropping systems in water-deficient areas.

针对种间竞争互补主导间作水分利用，但协同调控二者理论依据薄弱问题，以典型禾/禾、禾/豆间作模式为研究对象，在不同根系分隔、空间布局或供水条件下：(1)研究作物干物质累积、分配和水分生产力时空变化，早熟作物收获后晚熟作物的恢复效应，明确水分利用效率与种间竞争互补强弱消长的相关关系；(2)检测土壤含水量、水势和有效水分的时空动态，解析土壤水分迁移与种间竞争互补的关系，形成水分供给调控竞争互补的理论依据；(3)研究不同处理对作物光合、蒸腾、气孔导度、LAI和株高等水分生理生长指标的影响，揭示水分生理生态特性对种间竞争互补的响应机制；(4)探讨根冠协同发育与群体水分利用、种间竞争互补的相关关系，阐明根冠协同调控优化种间关系、提高水分利用效率的基本机理。集成不同尺度研究成果，形成间作水分高效利用的种间竞争互补调控理论。项目的实施将为深化种间关系研究，推动缺水地区间作发展提供重要理论和技术支撑。

针对种间竞争互补主导间作水分利用，但协同调控二者理论依据薄弱问题，以典型禾/禾、禾/豆间作模式为研究对象，通过不同耕作方式、根系分隔与施氮制度优化等方面研究了间作水分高效利用的种间竞争与互补机理。.间作具有保持较高土壤水势的作用，共生期，早熟作物小麦土壤水势均低于晚熟作物玉米带，相反，麦收后，小麦带土壤水势均高于玉米带，形成了间作作物在时间与空间上竞争互补利用土壤水分的动力学基础。小麦带免耕秸秆覆盖还田、玉米带地膜两年用高效较传统间作具有弱化共生期小麦对玉米带水分竞争，强化玉米独立生长期小麦对玉米带补偿利用土壤水分的优势，较传统间作降低水分竞争25.8%~58.9%，提高水分补偿42.2%~60.8%。高效模式具有弱化共生期小麦相对玉米种间竞争力，强化麦收后玉米补偿与超补偿效应，比传统间作种间竞争力降低27.1%~34.8%，麦收后间作玉米生长速率提高22.3%~25.3%。因此，高效较传统间作增产13.8%~17.1%，水分利用效率提高12.4%~17.2%。.地上地下完全互作促进间作作物带间水分竞争互补利用，密植增大带间水分潜在运移量。密植使共生期完全与部分互作处理潜在运移量分别提高34.3%和26.3%，玉米独立生长期分别提高41.1%和19.9%。同时，地上地下完全互作提高了种间竞争力及麦收后玉米的补偿生长效应，密植发挥了其正效应。间作较单作具有增产效应，地上地下部完全互作对籽粒产量的贡献率为23.7%，密植使其提高7.3%。.氮肥后移具有强化水分竞争互补利用的作用，氮肥后移30%处理下全生育期水分潜在运移量最大，共生期较地方传统提高49.0%~51.7%，玉米独立生长期提高59.3%~119.5%。氮肥后移30%较地方传统豌豆相对玉米种间竞争力提高5.5%~6.9%，提高豆收后玉米生长速率10.6%~11.5%。因此，氮肥后移30%较地方传统间作增产10.5%~15.2%，水分利用效率提高10.5%~17.7%。.总之，适宜的水分调控措施，合理密植与优化的施氮制度可通过协调种间作用关系，促进间作水分竞争互补利用，为间作高产及水分高效利用奠定基础。本研究集成不同尺度研究成果，形成间作水分高效利用的种间竞争互补调控理论，为推动缺水地区间作发展提供理论和技术支撑。

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