Study On Deep Litter System For Management Of Livestock Manure

Deep-litter systems have been developed as an alternative to management of domesticlivestock manure, which aims to "in-situ decomposition of livestock manure". In this paper, aseries of researches concerning this technology were investigated in farms, including experimentsindoor and breeding outside. Effect of deep litter and shallow litter, different litters and no litter onpig growth were compared and had a preliminary study to the composting discarded litter. Thepaper tried to present and validate that deep-litter systems was a new and effective managementmodel of livestock waste.By investigating the pollution about livestock manure in farms, it was found that strongobnoxious odor which was given off from wastewater of breeding farm seriously polluted the air.In the wastewater, the content of COD_Cr, BOD₅ and nitrogen reached 7029.12mg.L^-1.4231.53mg.L^-1 and 1760 mg.L^-1, respectively, which had already notably surpass the statestandards; in livestock manure, the amount of coliform far exceeded the national control standards;Salmonella was not detected in this investigation. Bacteria drug-resistant test results showed that,as use of antibiotics in farm, druy-resistant bacteria emerged and were discharged intoenvironment, which also increased the risk of bacterial resistance to the proliferation.In Jiangsu province, both the temperature and relative humidity were very high in summer,the effects of deep litter system on pig growth need to be evaluated. A pile experiment was carriedout on pig feed farm near Nanjing city. The results showed that the incidences of swine diseases inthe shallow and deep litter system were reduce to 19.7ï¼…and 25.1ï¼…, respectively. Only half ofthe quanlity oflabor force was needed in the hoggery and 82.07ï¼…of the water was saved. Thedaily increasing rate of pig was 7.23ï¼…. The deep litter system was a suitable breeding mode inNanjing under summer's climate.The results of microorganism inoculation indicated that pH of litter decreased, the contentsof NH₄^+-N and NO₃^--N were reduced to the lowest in 5d. Both of catalase and cellulose activitiesreached peaks in 5d, and urease activity reached the peak in 10d, while the activity of proteaseincreased continuously. Inoculating microorganism could accelerated the rate of pig manuredecomposition.After analyzing organic bedding surface sampling by undergoing breeding deep-litter systemprocess, the results show that, at the beginning, the temperature of litters rose dramatically, after30 days, the litter temperature consisted with atmospheric temperature; Moisture content in 6d stably saturated, and pH maintained between 6 and 8. The salt content of the materialsaccumulated. Organic substance and nitrogen remained stable after 6 and 30 days, respectively.Catalase activity remained stable in the fifth days; Cellulose activity and urease activity hasmaintained an upward trend. In the 60th days there was a downward trend of protease activity. Stat.of data results showed that the majority of environmental indicators in the late period (after 30days) was not significant. After one time of pig breeding, litters major enzymes remained active.The results also confirmed that the laboratory-developed inoculating microorganism couldincrease the degradation rate of livestock manure in organic litters.Composting the discarded organic litter results showed that, sawdust litters composted for 28days reached stability, mixed litter only need 14 days. The sawdust litters compost pH was 7.09,and organic substance of the compost content was 45.47%. Total nitrogen, phosphorus (P₂O₅) andpotassium (K₂O) contents were 1.97%, 3.50% and 1.07%, respectively. The mixed compost pHwas 7.34, organic substance of the compost content was 36.45%, and total nitrogen, phosphorus(P₂O₅) and potassium (K₂O) contents were 2.04%, 2.62% and 1.40%, respectively.The characteristics of the litter profiles in two deep-litter systems were investigated. Thefresh system has been used to raise pig for two months, and the old system had been used for twoyears, but stop raising pig for one month before sampling. The litter samples were collected fromthe top to the bottom of litter profiles, and analyzed for physical, chemical and bacterial properties.The temperature of the litter was significantly higher in fresh system than in old system, andincreased with litter profiles. No significant difference in pH of the litter was detected betweenfresh and old systems, but the values of pH decreased with litter profiles and ranged from 7.0 to7.6. The content of soluble salinity was significantly higher in old than in fresh system, andshowed more than 20 mg kg^-1 over 0-80 cm in the old litter profiles, which indicated saltaccumulation in the old litter system Total porosities were over 70% in both litter systems, and noeffect on biodegradation of pig manure Numbers of the fibre degraded bacterial, antinomyces, andmold were higher in the fresh litter than in the old litter system. The concentration of total N washigher in old than in fresh system, but the reverse results were obtained for the concentration ofinorganic N. The results suggest that the key to prolonging life of the deep litter system is tominimize salt accumulation and refresh the old system.