| In view of the unreasonable application of nitrogen fertilizer and insufficient attention to the nitrogen fixation capacity of legume root nodules,in order to give full play to the symbiotic nitrogen fixation effect of soybeans and reduce the amount of nitrogen fertilizer application,this experiment was carried out in the Agricultural Experiment Station of Tarim University.Spring soybeans（Xindadou 8,Shidadou 2,Heinong 61）and reseeding soybeans（Zhonghuang 30,Jiyu 202,Suinong 35）were used as materials,and the rhizobium（SMH12,T6,SN7）isolated from the saline-alkali land in Alar Reclamation Area.As the research object,it studied the effects of rhizobia inoculation on soybean nodulation,growth,dry matter accumulation and distribution,and yield under different nitrogen application rates.The selection of excellent rhizobia suitable for soybean growth and nitrogen fertilizer lever provide a theoretical basis for the popularization and application of soybean inoculation rhizobia in southern Xinjiang.The results show:The number of nodules and the dry weight of nodules of the tested soybeans gradually increased with the advancement of the growth process,and reached the maximum at the R6 stage.Nitrogen application significantly affects nodule formation.With the increase of nitrogen application rate,the number of nodules and the dry weight of root nodules increase first and then decrease.Compared with conventional nitrogen application,neither nitrogen application nor reduced nitrogen application can promote nodule formation.And the effect was more significant under the condition of reduced nitrogen application;the T6 and SN7-2 rhizobia has good compatibility with various soybean varieties,and the number of nodules was more.The diameter of nodule gradually decreased with the increase of nitrogen application rate,showing no nitrogen application>reduced nitrogen application>conventional nitrogen application;the inoculation of rhizobium had no significant effect on the diameter of nodule.With the increase of nitrogen application rate,soybean plant height,stem diameter,branch number,and number of branches increased significantly,but there was no significant difference in the number of main stem nodes.Rhizobium inoculation had little effect on soybean plant height.Increased application of nitrogen fertilizer and rhizobia inoculation,it has a significant effect on increasing the thickness of the stem,thereby making the stem thick and increasing the lodging resistance of the plant.Reasonable application of nitrogen fertilizer can delay the senescence of soybean leaves at the later stage,and increase the dry matter accumulation,leaf area index,and photosynthetic potential of the leaves at the later stage of soybean growth.Under the same nitrogen application rate,inoculation with rhizobia can increase the leaf area index to varying degrees,thereby increasing increasing leaf photosynthetic material accumulation.The leaf area index of spring soybean varieties and Zhonghuang30 of reseeding soybean under reduced nitrogen application conditions,and Jiyu 202 and Suinong 35 of reseeding soybean under conventional nitrogen application conditions increased significantly.The dry matter accumulation of each tested soybean showed a unimodal curve change throughout the growth period,and reached the maximum in the R6 stage.Spring soybean cultivars and Zhonghuang30 of reseeding soybean the dry matter accumulation reached the maximum under the condition of reduced nitrogen application.The dry matter accumulation of Jiyu 202 and Suinong 35 of reseeding soybean increased with the increase of nitrogen application.Xindadou 8,Shidadou 2,Zhonghuang 30,Suinong 35 inoculated with SN7-2 and T6,Heinong 61 and Jiyu 202 inoculated with SMH12 can promote plant growth and development and increase dry matter accumulation.Nitrogen application significantly affects soybean yield.Under the same rhizobia inoculation,application of nitrogen fertilizer can increase soybean grain yield by increasing the number of pods per plant,the number of seeds per plant,and the weight of 100 seeds;spring soybean cultivars and the yield of Zhonghuang 30 of reseeding soybean follow the application.The increase of nitrogen showed a trend of first rising and then decreasing.The yield of Jiyu 202 and Suinong 35 gradually increased with the increase of nitrogen application,and reached the maximum in conventional nitrogen application treatment.Under the same nitrogen application rate,the rhizobium inoculation can significantly increase the yield compared with the water dressing.The yield of Xindadou 8,Shidadou 2,Zhonghuang 30,and Suinong 35 responds to rhizobium in the trend of SN7-2>T6>SMH12>CK,and the response trend of Heinong 61 and Jiyu 202 to rhizobia is SMH12>SN7-2>T6>CK.The highest yield of spring soybean cultivar Heinong 61 inoculated with SMH12 rhizobia under reduced nitrogen application condition was5 565.8 kg·ha-1,and the highest yield of multiple seed soybean cultivar Suinong 35 inoculated with SN7-2 rhizobia under Conventional nitrogen application condition was 4 808.7 kg·ha-1.The results of two seasons of soybeans show that reducing the amount of basal fertilizer and inoculating high-efficiency rhizobia can promote the growth of nodules,increase the accumulation and distribution of dry matter,promote the increase in yield,and reduce the environmental impact of excessive nitrogen application harm. |
