Abstract: In this paper, a pot experiment was conducted to study the effects of different nitrogen application on nodule growth,nodulation and nitrogen fixation in soybean( Glycnie max L.).The results showed that nitrogen application affected nodule forming, growth and nitrogen fixation capacity significantly, nodule dryweight and nodule number showed atrend of increasing first and then declining,while nitrogenase activity and leghemoglobin concentration showed the trend of continuosly declining.Proper N application improved nodule growth,however N deficiency or excessive N use restrained nodule growth.There was an order of N100> N200> N50> N25> N0 for nodule dry weight and nodule number.At different growth stages,nodule dryweight showed a trend of increasing first and then declining from seedling stage to podding stage,and for nodule number was flowering stage> seedling stage.N application significantly decreased nitrogenase activity and leghemoglobin concentration with N rates increasing,showed an order of N0> N25> N50> N100> N200, suggested that N application decreased the efficiency of nitrogen fixation.The difference analysis showed that there was a signifi2 cant difference between N application(N25, N50, N100 and N200) and no N(N0) treatment.Therefore,from the view of the balance between N fertilization and nitrogen fixation,proper N application not only makes the best of nitrogen fixation function which economizing N fertilizer application but also obtaining higher output of soybean.

Key words: Nodule growth, Nitrogenase activity, Leghemoglobin concentration, N application, Soybean

CLC Number: 

• S13.1