豆科/禾本科间作作物群体对生物炭输入的响应及菌根效应

Biochar derived from pyrolysis or incomplete combustion of agricultural biomass waste is increasingly recognized as a multifunctional material for soil amendment, fertilizer carrier and carbon sequestration. Legume/cereal intercropping is a common agronomical practice in china, however, how response to soil biochar amendment have not been well studied. We hypothesize biochar amendment would improve total legume/cereal intercropping effects through two means: (1) improving soil fertility and increasing nutrient availability, and directly increasing crops effects of legume/cereal intercropping system; (2) improving mycorrhizal function and enhancing the facilitation between crops, and indirectly promoting intercropping synergistic effects. Thus, we would utilize field study and root compartment technique to test the hypothesis. Our objectives are as follows: (1) to illustrate the responsive characteristics of rhizospheric environments and crops growth to soil biochar amendment in legume/cereal intercropping system; (2) to reveal feedback effects of arbuscular mycorrhizae on legume/cereal intercropping system with soil biochar amendment. The results will offer theoretical basis for the application of biochar in agricultural sustainable development.

由生物质热解而成的生物炭（biochar）农用作为土壤改良剂、肥料缓释载体及碳封存剂备受世人关注。然而，豆科/禾本科间作体系作为我国重要的农业生产模式之一，如何响应生物碳的输入并不清楚。我们假设生物碳的输入能够提高豆科/禾本科的间作效应，并且由两种途径介导：（1）提高土壤肥力，增强养分有效性能，从而直接提高豆科/禾本科间作的作物效应；（2）提高菌根功能，增强作物种间的互惠作用，从而间接促进豆科/禾本科间作的作物协同效应。为此，本项研究拟通过野外田间试验和根箱根系分隔试验进行验证。本研究的目标是（1）阐明豆科/禾本科间作群体的根际环境和作物生长响应生物炭输入的变化规律；（2）揭示生物炭输入条件下，丛枝菌根对豆科/禾本科间作体系的调节效应。研究结果将为生物炭在农业可持续发展中的应用提供理论依据。

目前关于生物炭环境和作物效应的研究主要集中在温室盆栽试验与单一作物群体。作物间作套种作为重要的农业生产模式之一，如何响应生物碳的输入研究甚少。本研究以田间定位试验和同位素根箱分隔试验探讨了典型的豆科/禾本科作物间作模式对生物炭输入的响应特征及其内在机制。研究结果表明：（1）相比于对照（无生物炭处理），生物炭施用显著地提高了玉米/大豆和玉米/花生间作系统的生物学产量和经济学产量，增强了间作效应；（2）生物炭施用改善了间作系统土壤的理化性能，改变了土壤微生物（细菌和真菌）的群落组成，增强了土壤脲酶、过氧化氢酶和碱性磷酸酶的活性，提高了间作作物的根系活力、菌根侵染率、豆科作物固氮酶的活性和根瘤数量，促进了间作作物的光合性能和干物质积累；（3）叶片15N富积标记根系分隔受控试验证实了生物炭施用提高了玉米/花生间作体系氮素的转移量和转移率，且菌根网络对调控玉米/花生间作系统氮素的转移具有重要作用。研究结果为生物炭在间作系统中的进一步应用提供了理论依据，对推动生物质炭化利用，增强间作系统生产力，保障国家的粮食安全具有重要意义。