In recent years, the production of biogas in Qutacun Village, Fengrun District of Tangshan City has developed rapidly. The vegetable growers have skillfully applied biogas slurry and biogas residues to the production of tomatoes, which has increased production, reduced pesticide residues, and reduced pests and diseases. Occurs and reaches the pollution-free standard of vegetables. Now they are introduced as follows: First, biogas slurry soaked in biogas slurry contains water-soluble nitrogen, phosphorus, potassium and other trace elements and stimulants, can effectively promote the growth of seedlings, but also has the role of sterilization, inhibition of pests and diseases. The specific method is as follows: the tomato seeds are sunned for 1 to 2 days and then soaked in a filtered biogas slurry for 8 to 12 hours, that is, ready for seeding. Second, the use of biogas residue for soil improvement Biogas residue is the solid residue of organic matter after fermentation to produce biogas. In addition to containing a large number of available nutrients such as nitrogen, phosphorus, and potassium, it is also rich in organic fertilizers and humic acids, which can significantly improve the physical and chemical properties of the soil and fertility. 1. Pre-preparation: Biogas residue cannot be applied directly to farmland. Although most of the eggs are killed during the fermentation process, it is unavoidable that some living parasitic eggs exist. Therefore, before the use of adding 1% to 2% concentrated ammonia, you can also add 1% of urea or 2% to 3% of lime, stir evenly. Stacked for 2 to 3 days before use. If it is needed urgently, 50 kg of biogas residue and 1 g of trichlorfon solution can be mixed evenly, and then used overnight after being piled up. 2. Biogas residue base application: Before the tomato colonization, apply 2000-2500 kg of biogas residues per mu, and according to the tomato ripening, cultivation period and other different proportions of a small amount of fertilizer. For dry early maturing varieties, 15-20 kg of calcium phosphate, 10-15 kg of potassium sulfate, and 5 kg of urea are applied per acre; for late maturing varieties, the amount of nitrogen fertilizer should be appropriately controlled. Mix well and spread it on the surface and rotate it 30 centimeters. Third, using biogas slurry for topdressing and preventing biogas slurry is the residue of the organic matter after fermentation to obtain biogas. It contains not only nitrogen, phosphorus, potassium, trace elements, amino acids and other nutrients, but also contains butyric acid, indole acetic acid, vitamin B12 and other activities, resistant substances, has the dual role of promoting crop growth and disease control. The specific method is as follows: Top dressing: 7 to 10 days after the colonization of tomatoes, the combination of water topdressing biogas liquid and fruit ripening will dilute the water from the biogas fertilizer by 1:1 and then pour 1000 kg of mu into the water. When the first panicle begins to swell, 8 to 12 kg of urea are applied in combination with watering. The first fruit is nearly harvested. When the second fruit is inflated, the plant enters the full fruit period. Then, about 1500 kilograms of biogas manure is applied per acre, and 3 consecutive topdressing operations can achieve the purpose of strengthening the body, preventing premature aging, and improving fruit quality. 2. Foliar spraying: after filtering and clarification of biogas slurry with gauze, spraying biogas slurry with 1.5 times of fresh water on the foliage for 4 to 5 times can increase production by about 20%, and can effectively prevent tomato's early and late blight. And the occurrence of gray mold.