Effects Of Environmental Factors On The Nitrogen-fixing Quantity Of Nitrogen-fixing Bacteria In Agropyron Cristatu

The effects of nitrogen, phosphorus, temperature, carbon source and soil sterilized on the growth and nitrogen-fixing quantity of nitrogen-fixing bacteria by the potted Agropyron cristatu plant experiment. In order that the best ecological conditions of nitrogen-fixing bacteria is determined .It can offer theoretic basis for setting up a highly active and anti-athwart nitrogen-fixing system .The results are as follows:1. Within the scope of 0.5~1.5g/kg of the nitrogen content, the associative nitrogen-fixing bacteria have the more significant effect on the increase of nitrogen-fixing quantity of nitrogen-fixing system. The nitrogen-fixing quantity in fungi treatment averagely increase 13.6%.Especially,the increase of the nitrogen-fixing quantity of cole is the most at level of 1.0g/kg of nitrogen content, and respectively increase 23.4%.2. Within the scope of 0.85~0.925g/kg of phosphorus content, the associative nitrogen-fixing bacteria have the more significant effect on the increase of nitrogen-fixing quantity of nitrogen-fixing system. The nitrogen-fixing quantity in fungi treatment averagely increased 12.2%.Especially, the increase of the nitrogen-fixing quantity of cole is the most at level of 0.875g/kg of phosphor content ,and respectively increase 20.7%.3. Within the scope of 20~40℃of temperature, the associative nitrogen-fixing bacteria have the more significant effect on the increase of nitrogen-fixing quantity of nitrogen-fixing system. The nitrogen-fixing quantity in inoculation treatment averagely increase 16.7%.Especially, the increase of the nitrogen-fixing quantity of cole is the most at level of 30℃of temperature ,and respectively increase 29.2%.4. Adding malic Acid ,sucrose and glucose all can increase the nitrogen-fixing quantity of nitrogen-fixing bacteria in this experiment,but adding mannite and citric acid have not effect on the nitrogen-fixing quantity of nitrogen-fixing bacteria. When adding sucrose as carbon resource,the nitrogen-fixing quantity of nitrogen-fixing bacteria is the biggest.5. The nitrogen-fixing quantity of nitrogen-fixing bacteria in sterilized soil all more than in non-sterilized soil. The nitrogen-fixing quantity of the integrated nitrogen-fixing system on the sterilized soil has increase 11.5%than non-sterilized soil.