长期不同施肥制度对花生根际红壤磷素生物有效性的影响研究

Red soil contains a large amount of soil total phosphorus, but phosphorus is easily fixed and hence causes the deficiency of soil available phosphorus. Although the researches on organic acids, phosphate-solubilizing microbes, and root development and architecture have been developed recently, there have not been research using these methods systematically. In this study, we, with the assist of the red soil fertilizer experiment in Chinese Academy of Sciences Ecological Station, use molecular biology and biochemical method and three-dimensional scanning technology to (1) explore the interaction between different fertilizations and root exudates, rhizosphere microorganisms and root development; (2) investigate the effect of such interaction on peanut rhizosphere phosphorus absorption and utilization and (3) identify the mechanism for fertilization improving peanut rhizosphere phosphorus bioavailability and to understand phosphorus behavior and kinrtics in rehizosphere environment. According to the above research, we try to find a new way to regulate the level of rhizosphere nutrition，to promote phosphorus mobilization and, to improve crop utilization of soil potential phosphorus. A method of evaluating the phosphorus utilization efficiency would be establish based on the reasonable fertilization model. The result of rhizosphere basic research would directly guide practical production, and is of great practical significance on improving arricultural environment and increasing the yield of peanut.

针对红壤中总磷储备量大，但易被固定造成土壤有效磷极度缺乏等关键问题，同时基于土壤有机酸、解磷功能微生物以及根发育构型等单项措施研究的不足，本研究利用中国科学院红壤生态实验站肥料定位试验，通过分子微生物学和生物化学方法结合三维根系扫描技术，从＂作物根系－根际土壤－根际微生物＂生态微域角度，探讨长期不同施肥制度与作物根系分泌物、根际微生物、根系生长发育间的联系及其对花生根际磷素养分有效转化及作物吸收利用的影响，揭示其提高花生根际磷素有效性的机制及磷素在根际环境中的化学行为。通过以上研究，寻求调节根际营养环境、促进磷素活化、提高作物对土壤中潜在磷素利用率的途径，筛选合理的施肥模式，并在此基础上建立一套行之有效的优化施肥衡量评估办法。本研究结果对合理利用农业废弃物资源，改善农村生态环境，提高花生产量，实现根际微区基础研究直接指导宏观生产具有重要现实意义。

针对红壤中总磷储备量大，但易被固定造成土壤有效磷极度缺乏等关键问题，本研究利用中国科学院红壤生态实验站肥料定位试验辅以盆栽，通过分子微生物学和生物化学方法，从＂作物根系－根际土壤－根际微生物＂生态微域角度，探讨长期不同施肥制度与作物根系分泌物、根际微生物、根系生长发育间的联系及其对花生根际磷素养分有效转化及作物吸收利用的影响，揭示其提高花生根际磷素有效性的微生物学机制及磷素在根际环境中的化学行为。研究结果表明，红壤有效磷来源于钙、铁结合态无机磷及有机磷，长期化肥有机肥配施培肥提高有效磷源比例，有利于土壤真菌对有机磷矿化；红壤有效磷的释放激发红壤微生物活性，加速秸秆腐解，刺激硝化作用增强；有机培肥模式下，根际微生物互惠型促生作用增强，磷关键网络微生物代谢是土壤C-P和N-P耦合解磷新途径；相较于传统化肥，有机培肥减少红壤旱地地表径流，有效固持水分与养分，优化花生根系构型，提高土壤养分摄取；农田体系中，种间植物长期互作，植物通过根系乙烯释放改变根际微生物提高竞争适应性；以上研究对合理利用农业废弃物资源，改善农村生态环境，提高花生产量，实现根际微区基础研究直接指导宏观生产具有重要现实意义。