TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: The method for preparing microbial fertilizer, involves (A)(a) culturing the B.subtilis in inclined plane of 500 ml shake flask containing 100 ml culture medium, placing the shake flask in rotary table at 180 revolutions per minute (rpm), and maintaining culture temperature at 30 degrees C for 24 hours to obtain first-level seed culture, (b) inoculating 10% first-level seed culture in 500 ml shake flask, and performing culturing process to obtain second-level seed culture, (c) inoculating 10% second-level seed culture in 5000 ml shake flask containing 1000 ml culture medium, placing the shake flask in rotary table at 100 rpm, and performing culturing process at 30 degrees C for 24 hours to obtain third-level seed culture, (d) inoculating 10% third-level seed culture in 150 l seed tank containing 100 l fermentation-culture medium, performing culturing process at 28 degrees C and 0.05 MPa for 24 hours, and stirring the culture at 100 rpm and providing ventilation (V/V) at a rate of 1:0.5 during culturing process, and (e) inoculating 10% cultured strain of seed tank in 1.5 tons second-level seed tank containing 1 ton fermentation-culture medium, performing culturing process at 28 degrees C and 0.05 MPa for 24 hours, stirring the culture at 100 rpm and providing ventilation (V/V) at a rate of 1:0.5 during culturing process, centrifuging the obtained fermentation liquid using existing method, and freeze-drying the obtained B.subtilis, (B) preparing L.plantarum agent by (a) culturing the L.plantarum in 500 ml shake flask containing 100 ml culture medium, and maintaining culture temperature at 30 degrees C for 24 hours to obtain first-level seed culture, (b) inoculating 10% first-level seed culture in 500 ml shake flask, and performing culturing process to obtain second-level seed culture, (c) inoculating 10% second-level seed culture in 5000 ml shake flask containing 1000 ml culture medium, and performing culturing process at 30 degrees C for 24 hours to obtain third-level seed culture, (d) inoculating 5% third-level seed culture in 150 l seed tank containing 100 l fermentation-culture medium, performing culturing process at 30 degrees C and 0.05 MPa for 18 hours, (e) inoculating 5% cultured strain of seed tank in 3 tons second-level seed tank containing 2 tons fermentation-culture medium, and performing culturing process at 30 degrees C and 0.05 MPa for 22 hours, and (f) performing fermentation at low temperature and under vacuum, concentrating the fermented product to original volume of 45% to obtain bacterial concentrated liquid, adding carrier to the concentrated liquid, uniformly mixing the concentrated liquid with carrier in a weight ratio of 0.5:1, and drying the mixture in fluidized bed at 50 degrees C, and (C) preparing A.niger culture by (a) culturing the A.niger strain in inclined plane culture medium, and performing culturing process at 27 degrees C for 3 days to obtain first-level seed culture, (b) inoculating 100 g first-level seed culture in 500 ml Erlenmeyer flask, and performing culturing process at 30 degrees C for 3 days to obtain second-level seed culture, (c) inoculating 1000 g second-level seed culture in 5000 ml Erlenmeyer flask containing culture medium, and performing culturing process at 30 degrees C for 3 days, (d) inoculating the seed culture in fermenting tank containing sterilized culture medium, inoculating yeast in the culture medium, performing solid fermentation at 26-35 degrees C and humidity at 80-90% for 5-7 days, turning the material once for every 10 hours, where the culture medium is sterilized at 121 degrees C for 1 hour, and (d) drying and crushing the fermented product at 60 degrees C in fluidized bed or using other drying device till the water content of the product is less than 10%, and pulverizing the dried solid culture to obtain product of 60 meshes. The culture medium for B.subtilis, comprises 6% glucose, 1% yeast extract, 0.2% peptone and 1% calcium carbonate, where pH of the medium is 6.8. The carrier for L.plantarum, comprises 25 pts. wt. calcium carbonate and 12 pts. wt. dextrin. The culture medium for L.plantarum, comprises 1% cheese peptone, 1% beef extract, 0.5% yeast extract, 0.5% glucose, 0.5% sodium acetate, 0.2% citric acid, 0.1% Tween 80 (RTM: Polysorbate 80), 0.2% potassium monohydrogen phosphate, 0.02% magnesium sulfate heptahydrate, 0.005% manganese(II) sulfate monohydrate, 2% calcium carbonate and 1.5% agar, where pH of the medium is 6.8. The culture medium for A.niger comprises 70% bran, 15% crop straw, 5% bean cake powder, 10% corn starch and appropriate amount of water, where initial pH of the medium is natural. Preferred Composition: The fertilizer comprises 20 pts. wt. or 22 pts. wt. A.niger (CGMCC 7927) culture, 4 pts. wt. or 3 pts. wt. B.megaterium agent, 15 pts. wt. or 18 pts. wt. L.plantarum (CGMCC 7928) agent, and 30 pts. wt. or 32 pts. wt. B.subtilis (CGMCC 7926). Preferred Method: The step (B)(f) involves uniformly mixing the concentrated liquid with carrier in a weight ratio of 0.6:1. Preferred Component: The carrier for L.plantarum, comprises 30 pts. wt. calcium carbonate and 16 pts. wt. dextrin. ACTIVITY - Fertilizer.