Technology of extraction of compost extracts to make liquid fertilizer

Compost extracts is a good liquid fertilizer and bio-control agents，in order to obtain the extraction process parameters of compost extracts to make liquid fertilizer, 0.5 mol/L potassium sulfate and water (as control) were used to extract nutrient solutions from pig manure compost. The ratios of extracts to compost were designed as 1:10, 1:8, 1:6.67, 1:5 and 1:4, and the extracting time was set from 12 to 144 hours respectively under aerated and nonaerated conditions. Results show in terms of the compost extracts extracted with water, the optimum process parameters were 1:5 of extraction ratio, 72 hours of extraction under the aerated condition, while, those under aerated condition is 1:5 of extraction ratio and 36 hours of extraction for the compost extracts extracted with 0.5 mol/L potassium sulfate solution. We conclude that water and 0.5 mol/L potassium solution as extract reagents, using suitable extraction ratio and extracting time can get better effect of nutrient extraction at ambient temperature.