MANAGEMENT OF THE SAWDUST LITTER IN THE PIG-ON-LITTER SYSTEM OF PIG WASTE TREATMENT

In the 'pig-on-litter' system of livestock waste management, pig wastes were fermented in the sawdust litter with or without added microbial products in the substratum or to the feed. Weekly samples of the sawdust litter mere monitored for bedding temperature, moisture content, pH, urea, ammonia, nitrite, nitrate, phosphate, sulfphide, sulphate, chloride, fluoride, redox electrode potential reading, soluble and insoluble protein, CHN content, and sawdust particle sizes. It was found that for successful fermentation to take place, the moisture content must be kept low (about 50%). A bedding having good fermentation rates had higher pH due to trapped NH4+, and lower levels of urea, nitrite and nitrate, and soluble N, but had higher levels of insoluble protein and sulphate. Water-logging reduced aeration, promoted anaerobic fermentation, increased generation of sulphide, and accumulated substantial amounts of soluble nitrogen compounds which could not be accounted for as protein, urea, nitrite or nitrate. The changes in bedding composition suggested the release of volatile N products into the atmosphere while non-volatile P and Cl accumulated. F increased in proportion to the degree of moisture in the litter, suggesting that the source of water came mainly from drinking. A well managed system was found to effectively control the production of offensive odour.