A Study On Parameters Of Composting Dead Livestock And Poultry And Stock Capacity In Different Croping Systems

With the improvement of living standards in China, more meat, eggs and milk are demanded and more large-scale farms are established. As a result, manure, sewage, and dead livestock and poultry are increasingly produced, which has become one of the main pollution sources of environmental pollution in China. The traditional way of processing dung and dead livestock and poultry has many disadvantages, such as large investment, high cost, easy to spread diseases. The study focused on large scale livestock and poultry farms waste disposal problems, and studied on the harmless disposal of dead livestock and poultry, using rice husk and sawdust as bedding to go through a high temperature mature compost, and took Shandong Province as an example to estimate the suitable land grazing capacity in different cropping patterns, which provided theoretical basis for waste disposal and resource utilization of large scale livestock and poultry farms. The study draws the preliminary conclusion, mainly includes the following five experiments:Experimental 1 study of the varying pattern of bedding substrate. Choosing new padding pools, padding pools having been used 7 months and having been used 10 months, we analysed padding from surface layer, 30 centimeter, 60 centimeter and 90 centimeter deep. The result showed that, water content from the upper layer to lower layer increased significantly(P<0.05), the pH of new litters was lower than the pH of used litters(P<0.05). C/N decreased significantly in the treatment process(P<0.05), and the organic matter in used padding pools were significantly higher than that in the new ones(P<0.05).Experimental 2 study of the parameters of the litter disposal of dead livestock and poultry were researched. We chosen new padding pools, padding pools having been used 7 months and having been used 10 months and buried a certain amount of dead pigs in winter, padding pools having been used 5 months and having been used 15 months and buried a certain amount of dead pigs in spring and padding pools having been used 8 months and having been used 18 months and buried a certain amount of dead pigs in summer and buried a certain amount of dead broilers into the padding pools inoculated with mixed strains and without those. The variation of the temperature of surface layer, 30, 60 centimeters and room temperature were recorded. In addition, padding buried in the above-mentioned pools were collected at the first, 3th, 7th, 14 th, 21 th and 28 th day and the degradation rate of animal bodies were determined. The result showed that the surface layer’s temperature is lowest and the 30 centimeters’ deep litter’s temperature is highest, which could keep more than 55℃ for 3 weeks. Besides, along with the fermentation time, the water content, C/N obviously decreased(P<0.05), but the pH increased significantly(P<0.05), and organic matter was not significance(P>0.05). The dead animal bodies were completely disposed for 3-4 weeks. There was not significance between the treatment inoculated with mixed strains and without those strains(P>0.05), but the treatment inoculated with mixed strains could dispose the dead broilers more completely.Experimental 3 study of the variation of pathogenic microorganism in the process and Escherichia coli was chosen as the indicator. We analysed new padding pools, padding pools having been used 7 months and having been used 10 months in winter, padding pools having been used 5 months and having been used 15 months in spring from surface layer, 30 centimeter, 60 centimeter and 90 centimeter deep. The result indicated that only some surface layer of padding we collected was found Escherichia coli positive and the others were not found, which declared that the high temperature the padding made can kill pathogenic microorganism, realizing the harmless treatment of dead livestock and poultry.Experimental 4 study of the available time of the padding. We took samples from surface layer, 30 centimeters, 60 centimeters and 90 centimeters of a padding pool before used and 1, 3, 5, 7, 9, 11 and 13 months after used to analyse. The result showed that the pH of litter tooken from the padding pool which has been used 7 months began to increase significantly, C/N began to decrease remarkablely and organic matter was not significance. From the result we can infer that the best time to supply fresh litter to padding pools is 7 months after used, when the activity of microbe in the padding began to decrease because the carbon source was deficiency and the micobe could not resolve the organic matter.Experimental 5 study of the suitable and grazing capacity in different cropping patterns. The nitrogen and phosphorus requirements under three cropping systems, wheat-corn production, apple production, and vegetable production, were estimated as well. A mathematical model was built to determine the stock capacity based on the principle of ecological balance. The result showed that the vegetable cultivation system had higher nitrogen and phosphorus outputs while the apple production system had lower nitrogen and phosphorus outputs, compared to grain production system. For vegetable cultivation, the stock capacities under greenhouse and open-field production patterns were 4.5 and 3.8 hog unit/ha, respectively. The stock capacity at apple production system was 1.2 hog unit/ha. In grain production, the stock capacity was dependent of the straw returning to field and the suitable stock capacity for wheat/maize production system was 3.9 hog unit/ha in case of no straw returning to field. The minimum farmland needed for the effective usage of animal manure produced from a pig farm of 1000 breeding sow was 188.7, 833.3, and 256.4 ha under vegetable, apple, and grain production system, respectively.In summary, the harmless treatment of high temperature composting reactor system can be achieved using the mat of dead livestock and poultry; In the recycling ecological model of animal husbandry-cropping system, the suitable stock capacity was from 1.2 to 4.5 hog unit/ha, basing on different cultivating systems. The present result lays a foundation for the regional planning of animal husbandry and manure and farmland management.