| At present, a series of environmental problems, such as soil acidification, compaction, salinization, were caused due to a large number of and long-term application of N, P, K fertilizer in traditional agriculture production of China, though, to a certain extent, it relieved the food security issues. It is important to apply appropriate biofertilizer, which could improve fertilizer efficiency, control disease and gradually repair the soil, on the way to sustainable development of agriculture. So it has broad market prospects to produce low-cost biofertilizer containing a large number of probiotic. And it is also consistent with the strategy of green agriculture in China. Traditional probiotic liquid fermentation process is complex and high cost, as consequence, it limits the application of biofertilizer in agriculture. Hence, it is necessary to develop a low-cost probiotic product and its derivative that suitable for agriculture.Firstly, four probiotic Bacillus were identified in ecology and molecular biology, and some of its properties were studied. Then we researched the production process of low-cost biofertilizer which were high in probiotic by solid-state fermentation. After optimized procedure we found that optimal conditions of Bacillus subtilis L7 in solid fermentation was:85%furfural residue,10% liquid glucose and 5% wheat bran, under 60% initial moisture, temperature 30℃, initial pH 7.0, inoculum 5×106 CFU/g, and turned over one time a day. Finally we obtained biofertilizer containing L7 number 2.48×1010 CFU/g and 2.40×1010 CFU/g spores with spore rate 96.7%. And the L7 number was 3.26×1010 CFU/g,31.1% higher than before under the 100 kg scale, and the fermentation time reduced from 6 to 3 days. Meanwhile we successfully got products with Bacillus licheniformis D62.48×1010 CFU/g, Bacillus megaterium J3 1.02×1010 CFU/g and Bacillus mucilaginosus G14 8.08×109 CFU/g respectively by small scale solid-state fermentation. The number of viable cells was higher than the corresponding liquid fermentation process. And this solid-state fermentation method had obvious competitive advantage due to its low cost.Then we studied the effect of compound biofertilizer, which mixed the production of solid-state fermentation with fertilizer (NPK 16:16:8), on the growth of rape (Brassica campestris L. Sp) under pot experiment. Results showed that the use of compound biofertilizer B3 effectively improved the dry weight of roots and shoots, 46.1% and 34.1% higher than control respectively, demonstrating that the biofertilizer could promote the growth of the crop.Finally, we analyzed the microflora of plant rhizosphere soil in pot experiment with DGGE method. Results indicated that, on the 30th day, biofertilizer B3 were significantly lower than the control at 206% and 47.7% in the richness and diversity of bacteria, respectively. While the values were 233% and 47.8% in the two aspects of fungi. On 60th day, biofertilizer treatments had a remarkable effect only on the stuctrure of fungi. The influence of biofertilizer B3 on fungal richness and diversity had obvious changes,98.2% and 26.7% lower than control, respectively. Demonstrating that biofertilizer produced by solid-state fermentation with its compound biofertilizer played an inhibitory effect on soil fungi. Therefore, the compound biofertilizer will have favorable application prospects on the control of soil-borne fungal diseases of crops in the future. |
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