The invention discloses a
drug fertilizer for tomato production based on concentrated liquid of
biogas fermentation slurry, which is characterized by consisting of the following compositions in weight percentages: 95 to 98 percent of the concentrated liquid of the
biogas fermentation slurry, 25 percent of
prochloraz, 0.001 to 0.003 percent of missible oil, 80 percent of
mancozeb, 0.01 to 0.03 percent of
wettable powder, 0.8 to 1.2 percent of
ethylene glycol, 0.8 and 1.2 percent of
kerosene, and the balancing being auxiliary materials. A method for preparing the concentrated liquid of the
biogas fermentation slurry is characterized by comprising the following steps: taking the biogas fermentation slurry taken from a biogas generating pit or a reactor with normal fermentation and gas generation, making the biogas fermentation slurry pass through a steel
sieve the aperture of which is 20 millimeters, and sedimentating the
effluent to remove larger suspended substances; filtering the
effluent through a
sand filter and an
ultrafiltration membrane sequentially to retain substances of which the molecular weight is larger than 100, 000 Da; causing the liquid penetrating the
ultrafiltration membrane to enter a
nanofiltration tank from the top down; arranging a
nanofiltration membrane on the lower part of the
nanofiltration tank to only allow the substances of which the molecular weight is less than 200 Da to pass through; and when the main
fertilizer content index is 10 times or more than 10 times higher than that of the original biogas fermentation slurry, qualifying the concentration. The
drug fertilizer integrates the functions of sterilization,
disease prevention and fertilizing, reduces the labor intensity, improves the labor efficiency, and effectively reduces the agricultural expenditure for farmers; besides, the
drug fertilizer solves the problem of recycling the biogas fermentation slurry produced in the process of utilizing
agricultural waste resources to .