Study On Association Nitrogen Fixation With Azotobacter Chroococcum And Bermudagrass

As a kind of turfgrass,bermudagrass is widely used in the construction of dome stic and foreign turf ecological environment.It has high ecological value and econom ic value.However,the application efficiency of nitrogen fertilizer in bermudagrass is low,and the ecological environment of bermudagrass is easily destroyed by applying more nitrogen fertilizer.Therefore,The way to improvethe utilization efficiency of nit rogen in bermudagrass and improve the utilization of nitrogen in bermudagrass have become a problem to be solved.In this study,bermudagrass was used as material,by using sand culture and soil culture potted plant,through bacteria liquid and urea treatments,Studying the morpho logy and physiological change of bermudagrass.On this basis,through the research i n different temperatures,studying the effect of azotobacter chroococcum and urea on the soil nutrient,soil related enzyme activity,exploring the suitable bacteria liquid te mperature.The results were listed as follows:1.The results of the sand culture pot experiment of bermudagrass showed that th e applied urea and bacteria liquid after 30 d,The growth of bermudagrass was better promoted.Leaf length,stolon length,stem diameter,root length,and the ground part of the production of bermudagrass were significantly improved(P<0.05),the urea cou Id significantly increase the leaf width,color rate(P<0.05),chlorophyll content and to tal nitrogen content of bermudagrass.Azotobacter chroococcum significantly improvee d the bermudagrass total nitrogen content(P<0.05),and had no significant effect on c olor rate and chlorophyll content;The combination of urea and azotobacter chroococc um had a better promoting effect on the growth of bermudagrass,color rating,chloro phyll content and total nitrogen content(P<0.05).Azotobacter chroococcum could imp rove the utilization efficiency of ureain bermudagrass.2.In this study,urea and bacteria liquid were used to study the bermudagrass ph otosynthesis.The results showed that in different treatments after 20 d,accumulation of dry matter,chlorophyll content and total nitrogen content of bermudagrass were in creased significantly(P<0.05),urea could improve the chlorophyll fluorescence related indicators,photochemical efficiency of bermudagrass,so urea could improve the phot osynthesis of bermudagrass,azotobacter chroococcum had no significant effect on the chlorophyll fluorescence related indicators of bermudagrass(P>0.05),but the mixture of urea and azotobacter chroococcum could significantly increase the photosynthesis o f bermudagrass,azotobacter chroococcum could improve the effect of urea to promot e the photosynthesis of bermudagrass;Through the correlation analysis of the content s of dry matter,chlorophyll,total nitrogen and chlorophyll fluorescence of bermudagr ass,it was found that the contents of chlorophyll,total nitrogen and chlorophyll fluor escence were significantly correlated with each other(P<0.05).In addition,the experi ment also found that there were significant differences in dry matter(P<0.05),chloro phyll,total nitrogen content and related indicators of chlorophyll fluorescence in berm udagrass only at 20 d.However,with the extension of time,urea was decomposed a nd utilized,and the activity of azotobacter chroococcum decreases,resulting in the di fference gradually disappeared.3.Soil culture pot experiment results of bermudagrass showed that after applying urea and bacteria liquid after 20 d,The growth characteristics of bermudagrass was s imilar to sand culture results in experiment 1.In 20℃ and 30℃,urea and azotobact er chroococcum could significantly improve the growth of bermudagrass(P<0.05).Th e combination of urea and azotobacter chroococcum could more significantly improvet he growth of bermudagrass(P<0.05).In 10℃,there was not any effect;in 30℃,ure a and azotobacter chroococcum could significantly increase the auxin secretion of ber mudagrass(P<0.05),and the effect of azotobacter chroococcum was better than urea.In the study of related parameters of soil,in 20℃ and 30℃,urea and azotobacter c hroococcum significantly increased the soil pH(P<0.05),urea significantly reduceed t he soil urease activity,azotobacter chroococcum significantly increased the soil nitrog enase activity(P<0.05),within the three temperature,urea significantly increased the content of soil alkaline hydrolysis(P<0.05),azotobacter chroococcum in 20℃ and 30℃ could significantly increase the soil available nitrogen content(P<0.05);In additi on,the experiment also found that the soil available nitrogen at different temperature s had different effects on the growth of bermudagrass.In 30℃,the soil available nit rogen have significant correlation with the leaf length,and the soil available nitrogen have significant correlation with the stolon length,root length and chlorophyll content of bermudagrass in 20℃(P<0.05).