Effect Of Mixed Planting Of Vicia Sativa Or Fertilization On Weight Loss And Efficiency Enhancement Of Avena Sativa Pastures

In this study,the mixed grassland of annual forage grass Vicia sativa and Avena sativa was used as the research object.In 2020,a pot experiment of mixed planting of oats and arrow pea was carried out in the No.77 Regiment of Zhaosu County,Yili Prefecture,Xinjiang Uygur Autonomous Region.Field trials.Legume to grass ratio（0:100,12.5:87.5,25:75,37.5:62.5,50:50,62.5:37.5,75:25,87.5:12.5,100:0;9 treatments in total）as a change factor in the community structure of legume and grass mixed pastures.From the perspective of the biological nitrogen fixation of legume pastures,the changing factors of the population structure analyze the effects of the nitrogen fixation characteristics of legume pastures and rhizobia on grassland nitrogen yield and production performance under different mixed sowing ratios,focusing on the analysis of the nitrogen fixation performance of rhizobia and legume pastures Nitrogen fixation ability,AM fungal infection characteristics and nitrogen transfer,root architecture and the internal relationship of nitrogen absorption,clarify the apparent balance effect of mixed legumes and system external nitrogen input.The following main results were found:（1）The nitrogen yield of Avena sativa increased by 6.09%～50.99%compared with the mixed planting of Vicia sativa in the monoculture of Avena sativa,and the nitrogen nutrition competition rate increased exponentially as the proportion of mixed seeding of oats decreased.There was no significant difference in nitrogen fixation rate of Vicia sativa in mixed sowing（P>0.05）,but it was significantly higher than that in unicasting（P<0.05）;the highest nitrogen fixation amount in H1 treatment was 2.20 g·m^﹣2.The nitrogen transfer rate between different mixed sowing treatments ranged from 6.5 to 10.65%,and the nitrogen transfer rate was 0.41 to0.97 g·m^﹣2;AM fungi can significantly improve the nitrogen transfer ability of the legume and grass mixed system（P<0.05）.The biological contribution rate showed a downward trend with the increase of the proportion of mixed sowing Vicia sativa.（2）Mixed planting of Vicia sativa can increase the grass yield of Avena sativa grassland.Compared with the mixed planting treatment（H4,H1）of CK1,the grass yield increased by14.22%and 12.99%,respectively.From the point of view of the contribution of nitrogen application treatment and mixed sowing treatment to increasing yield and nitrogen yield,N1treatment is similar to H1 and H4 treatments.It shows that the contribution value（apparent balance effect）of mixed sowing treatment and N1 treatment on grassland is the same,that is,mixed sowing 12.5%（H1）or 50%（H4）Vicia sativa has the potential to replace 100 kg·hm^﹣2nitrogen（N1）.（3）There are two reasons why mixed planting Vicia sativa in Avena sativa grass can achieve the goal of weight loss（nitrogen）efficiency.One is that mixed planting Vicia sativa generally increases the nodulation number,nodule fresh weight and nitrogenase activity of Vicia sativa,and at the same time improves the bean.The frequency and intensity of AM fungi infection in the mixed-grain planting system,thereby forming a nitrogen fixation and transfer network with the nodule nitrogenase activity as the link,which promotes the nitrogen transfer and nitrogen fixation capacity of the legume-grass mixed planting system;the second Avena sativa is in the mixed planting system It is in a competitive position,but has strong inter-species compatibility（RYT>1）.At the same time,as the proportion of Avena sativa mixed sowing decreases,the morphological characteristics of the root system of Vicia sativa and oats show a complementary trend,that is,the forage in the mixed sowing system The plastic change of the root system optimizes the resource allocation mode.（4）The relative contributions of aboveground and underground factors to the yield and nitrogen yield advantages of the mixed planting system of Avena sativa+Vicia sativa mixed planting are 37.31%,62.69%and 36.36%,63.63%respectively,which is comprehensively reflected that the contribution of the underground part is greater than that of the above-ground part The ratio is about 1/3 of the above-ground part and about 2/3 of the underground part,indicating that the nutrient flow between the roots of various species in the legume-grass mixed planting system plays an important role in maintaining the advantage of mixed planting.