Effect of biogas residue feed on swine carcass and meat quality and nutrition content Availability of potassium as affected by biogas residue reasonable application Effects of combined application of biogas residues and chemical fertilizers on greenhouse tomato’s growth and its fruit yield and quality. Analysis of nutritive value of biogas residues and heavy metal content in feedstuff with biogas residues and the pork fed on it Pig farm-cropland configuration under typical waste treatment mode— A case study of direct anaerobic fermentation of manure Cultivating A.Polytricha with forage and biogas residues and the effect of fungi residues on soil improvement