Research On Ecological And Physiological Mechanism Of Composite Intercropping System Of Oat||Soybean And Oat||Mung Bean

Legume-cereal intercropping can use resources efficiently, enhance grain yield and play a crucial role in maintaining nitrogen (N) balance. Most of the previous studies focused on yield advantage, interacting effects of the above ground, insect, disease and weeds control. However, research on the relationship of above and below ground calling for further enhancement and improvement, especially in oats and legumes intercropping system. Our research used root barrier method,15N dilution method and Q-PCR technology, studies the effect of soybean (mungbean)-oat intercropping system on crop growth, above and below ground relationship, legume nitrogen fixation and soil N fixation microbial diversity. In order to provide a theoretic guidance, we established a systematic research on legume-cereal intercropping system in Baicheng, China. Main results are as follows:(1). Soybean-oat and mungbean-oat intercropping system has a yield advantage, enhance land use efficiency. Land equivalent ratio (LER) was1.36～1.43and1.24～1.4, while land use efficiency was36～43%and24～40%, respectively. Harvest index and dry matter accumulation of intercropped oat were higher than solo oat.(2). Intercropping significantly enhanced soybean N fixation efficiency at mature stage, but intercropping decreased mungbean N fixation efficiency. Intercropping enhanced legume nitrogenase activity, especially about mungbean.(3). In mungbean-oat intercropping system, oat have more competitive ability comparing to mungbean, while in soybean-oat intercropping system, they do not have a competitive affect with each other. Thus, the dominant interaction between legumes and oat was positive in soybean-oat system, while negative in mungbean-oat system.(4). Intercropped with legumes significantly enhanced oat relative chlorophyll content and net photosynthetic rate in leaves. Intercropped legumes relative chlorophyll content increased1.6%-32.6%and do not have significant in net photosynthetic rate.(5). Intercropping can enhance oat root activity and showed an increased first and then decreased trend with time extension. Besides, the nifH gene copy number of oat rhizosphere soil was increased in soybean-oat and mungbean-oat intercropping system, The nifH copies in the rhizosphere of oat intercropped with mung bean was high than that of oat intercropped with soybean during the whole growth period(6). In soybean-oat intercropping system, the contribution of above and below ground parts to system yield was80%and20%, respectively. On the contrary, above and below ground parts contribute64.1%and35.9%in mungbean-oat intercropping system.(7). Interspecific interaction studies of Oat‖Soyean and Oat‖Mung bean have shown that the nodule number and nodule weight were significantly higher in no barrier than that in barrier treatments, which indicated that interspecific root interactions promoted the ability of nodulation of legume crops. At the same time,the study found that nitrogen concentration of organ of oat had inproved in intercropping system. Nitrogen concentration was lower in solid barrier than in no barrier system.However nitrogen concentrations of soybean had decreased and improved nitrogen concentrations of mungbean in intercropping system.meanwhile solid barrier was higher than no barrier treatments.