Effects of pile size and packaging on swine manure composting

The studies were conducted on the effects of pile size on composting and the feasibility of packaged composting. The mixture of swine manure and straw was divided into 800 kg, 400 kg and 200 kg. Each of them was composted for 40 days. Another mixture of 800 kg, which was first composted for 10 days, was packaged into several bags to compost for 40 days. The pile temperature was measured twice a day. The C/N ratio, soluble carbon content, total content of humic substance, ammonia-nitrogen and nitrate-nitrogen of the mixtures were sampled and measured after composting for 1, 5, 10, 20, 30 and 40 days. The results indicated that the mixtures of 400 kg and 800 kg reached maturity after composting for 40 days. However the organic matter could not be decomposed thoroughly in the mixture of 200 kg. Compared with the unpackaged one, the packaged mixture of 40 days had a lower C/N ratio, approximate content of humic substance and ammonia-nitrogen, and higher content of soluble carbon and nitrate-nitrogen. Packaged composting is suitable for wide use in countryside and on animal farms because of simplicity, low cost, and little land occupancy.