燕麦–绿豆间作效应及氮素转移特性

Intercropping Effect and Nitrogen Transfer Characteristics of Oat–Mungbean Intercrop

为探究燕麦(Avena sativa)–绿豆(Phaseolus radiatus)间作效应及氮素转移特性,在不施氮肥的大田试验条件下,设置3种种植模式(燕麦单作、绿豆单作和燕麦–绿豆间作),采用传统挖根法和^(15)N同位素标记法进行研究。结果表明,间作系统中燕麦侵袭力强于绿豆,绿豆生长受到抑制。整个生育期,间作燕麦地上部干物质积累量比单作增加14.9%–33.1%,2年成熟期间作燕麦的氮素积累量比单作分别提高53.1%和44.8%;间作减少了开花结荚期绿豆氮素积累量和根瘤重量,降低了绿豆的固氮效率,绿豆的固氮效率2年平均降低23.7%,生物固氮量平均减少11.66%。间作绿豆向燕麦的氮素转移率2年平均值达31.7%,氮素转移量为212.16 kg·hm^(–2)。燕麦–绿豆间作降低了开花结荚期绿豆的根瘤固氮酶活性和固氮效率,但绿豆体内氮素转移增加了燕麦对氮素的吸收利用,实现了地上部与地下部生长的相互调节和促进,优化了农田生态系统的氮素管理。

To explore the intercropping effect and nitrogen transfer characteristics of oat and mungbean,three planting patterns,oat monocropping,mungbean monocropping,oat–mungbean intercropping,were investigated with both root-digging method and^(15)N isotope labelling method.The results showed that in intercropping system,oat displayed higher invasiveness than mungbean,whose growth was inhibited.The dry matter accumulation of oat shoot was 14.9%–33.1%higher in intercropping than in monoculture in the whole growing stages.Compared with monocropping,the nitrogen accumulation of oat at two year mature stages was increased by 53.1%and 44.8%,respectively.The intercropping system reduced nitrogen accumulation,nodule weight at flowering and pod stage,and nitrogen fixation efficiency of mungbean.The total nitrogen fixation efficiency of mungbean decreased by 23.7%and the biological nitrogen fixation decreased by 11.66%on average for two years.The nitrogen transfer rate of intercropped mungbean to oat reached 31.7%,and the nitrogen transfer amount was 212.16 kg·hm^(–2).The oat–mungbean intercropping decreased nodule nitrogenase activity and nitrogen fixation efficiency of mungbean at flowering and pod stage,but nitrogen transfer in mungbean increased nitrogen uptake and utilization of oat,realized the mutual regulation and promotion between the growth of above and below ground,and meanwhile,optimized the nitrogen management system in farmland ecosystem.