"Bacterial fertilizer" is a non-polluting new compound biological fertilizer developed from the natural nitrogen-fixing bacteria species, which has been scientifically formulated and combined . When applying bacterial fertilizer in farmland, the following points should be noted: It is not appropriate to apply biological fertilizer to soils with high sulfur content and rust fields because sulfur can kill biological bacteria. For the paddy field, the fertilizer is generally not applied, and the spray method is more effective. It is not advisable to apply bacterial fertilizer to farmland under high temperature, low temperature and drought conditions. The optimum temperature for applying the bacterial fertilizer is 25-37 ° C, and the application effect is poor when it is lower than 5 ° C or higher than 45 ° C. When the soil water content is between 60-70%, the fertilizer efficiency of the bacterial fertilizer is better. Mixing should not be mixed with fungicides, insecticides, herbicides and sulfur-containing fertilizers (such as potassium sulfate) and straw ash, because these drugs and fertilizers can easily kill the bacteria. If you must use the above drugs, fertilizer, you can first apply the fertilizer, after 48 hours, then fight drugs and weeding. When using the bacterial fertilizer for seed dressing, it is forbidden to mix the seeds mixed with the bacterial fertilizer with the seeds mixed with the fungicide. In addition, it should be prevented from mixing the bacterial fertilizer with the unfertilized farmyard manure. Due to the quantity system, for the field where fertilizer is applied for many years, the application of biological fertilizer can not reduce the application of chemical fertilizer and organic fertilizer. Because crops can be dependent on fertilizers, using biological fertilizers instead of nitrogen fertilizers, crops can't adapt at once. The amount of bacterial fertilizer should be replaced by 30%, 40% and 60% of the nitrogen fertilizer in the first, second and third years respectively . Phosphorus and potassium fertilizers can only make up and cannot be reduced. Due to the time-adjusted biological bacterial fertilizer is not a quick-acting fertilizer, it is best applied in the nutrient critical period of the crop and 7-10 days before the nutrient mass absorption period.