| Agricultural waste is a kind of organic matter which is discarded in the whole process of agricultural production. Usually agricultural waste is mainly based on crop straw and livestock and poultry manure. With the rapid development of agriculture and animal husbandry in China, agriculture and animal husbandry industry in China has been embodied in the development of intensive, large-scale and efficient development, and therefore more and more agricultural waste. But the low efficiency of current use of straw, which directly burned in the field, not only has large quantities of CO2 and other greenhouse gases and harmful gases pollute the atmosphere, but also caused plenty of waste recycling use of resources. In this study, chicken manure, pig manure, cow dung and straw as the raw material, according to the different C/N ratio of compost. Through the research of chicken manure, pig manure, cow dung and straw high temperature aerobic composting process, the dynamic changes of different physical index, chemical index and greenhouse gas(CO2, CH4 and N2O), and to explore the variation of composting greenhouse gas changes and carbon and nitrogen substances. The main conclusions are as follows:1. CO2 emission occurred mainly in the pre composting. In the chicken manure and straw compost, C/N=25(treatment 2) CO2 average emission rate is maximum, 106.50 mg·kg-1·h-1. C/N=20(treatment 1) 62.3% higher than C/N=30(3) 37.2%. In the cow dung and straw compost, C/N=25(treatment 5) CO2 average emission rate is maximum, 109.84 mg·kg-1·h-1. C/N=20(treatment 4) 51.5% higher than C/N=30(6) 33.9%. In the pig manure and straw compost, C/N=25(treatment 8) CO2 average emission rate is maximum, 101.60 mg·kg-1·h-1. Higher than C/N=20(treatment 7) 54%, higher than the C/N=30(9) 38.5%. It showed that C/N was the most suitable microbial activity, and the CO2 emission was the best when the compost was 25.2. CH4 emissions were mainly concentrated in the high temperature stage of composting, with the decrease of CH4 emissions from the composting temperature, and the CH4 emission at the later stage of composting was kept at a low level. In the chicken manure and straw compost, C/N=25(treatment 2) the average emission rate of CH4 maximum, 3.75 mg·kg-1·h-1. Higher than C/N=20(treatment 1) 82.9%, higher than the C/N=30(3) 35.4%. In the cow dung and straw compost, C/N=20(treatment 4) the average emission rate of CH4 maximum, 3.37 mg·kg-1·h-1. C/N=25(treatment 5) 1.8% higher than C/N=30(6) 10.1%. In the pig manure and straw compost, C/N=25(treatment 8) the average emission rate of CH4 maximum, 3.51 mg·kg-1·h-1. C/N=20(treatment 7) 66.4% higher than C/N=30(9) 24.5%. In chicken manure and pig manure, CH4 emission from C/N=25 processing, show strong microbial activity in the C/N=25, consume a lot of pile body oxygen leads to partial anaerobic. CH4 emissions and cow dung processing C/N=20, showed that different material composting differences.3. In the composting of chicken manure and straw, C/N=20(treatment 1) TOC decreased the maximum, 141.4 g·kg-1, TN content increased, 26.9 g·kg-1, C/N=25(2) at the end of the compost C/N is most appropriate for 15.6; in the composting of cow dung and straw,(C/N=25 5) the content of TOC decreased the maximum, 134.6 g·kg-1, C/N=20(treatment 4) and increased the content of TN, 3.6 g·kg-1, C/N=30(6) at the end of the compost C/N is most appropriate for 14.27; in the composting of pig manure and straw, C/N=25(treatment 8) TOC content. The biggest drop, 100.5 g·kg-1, C/N=30(treatment 9) and increased the content of TN, 13.9 g·kg-1, C/N=20(7) at the end of the compost C/N is most appropriate for 12.34.4. In chicken manure and straw compost treatment, C/N=20(treatment 1) ammonium nitrogen(NH4+-N) maximum peak is 5.17 g·kg-1; in cow dung and straw compost treatment, C/N=20(treatment 4) ammonium nitrogen(NH4+-N) maximum peak is 3.47 g·kg-1; in pig manure and straw compost treatment, C/N=20(7) ammonium nitrogen(NH4+-N) maximum peak for 2.23 g·kg-1. Show high activity processing of microbial C/N=20, organic nitrogen leads to rapid decomposition of ammonium nitrogen(NH4+-N) increased. In the chicken manure and wheat straw compost. C/N=20(treatment 1), C/N=25(2) and C/N=30(treatment 3) nitrate nitrogen(NO3--N) content were increased by 0.125 g·kg-1, 0.072 g·kg-1, 0.069 g·kg-1. Among them, in the chicken manure treatment C/N=20(treatment 1) at the end of nitrate nitrogen(NO3--N) content increased greatly. In cow dung and straw compost, C/N=20(treatment 4), C/N=25 processing(5) and C/N=30(6) the content of nitrate nitrogen(NO3--N), respectively, an increase of 0.154 g·kg-1, 0.185 g·kg-1, 0.17 g·kg-1. Among them, in the treatment of cow dung in C/N=25(treatment 5) at the end of nitrate nitrogen(NO3--N) content increased greatly. In pig manure and straw composting. C/N=20 handle(7), C/N=25(8) and C/N=30(9), nitrate nitrogen(NO3--N) content were increased by 0.215 g·kg-1, 0.209 g·kg-1, 0.127 g·kg-1. Among them, in the manure treatment in C/N=20(treatment 7) at the end of nitrate nitrogen(NO3--N) content increased greatly.5. A sharp increase in the heating stage and high temperature composting stage NH3 emission rate in the cooling phase decreased and tended to be stable, high temperature composting is the main stage of NH3 emission. In the chicken manure and wheat straw compost. C/N=20(treatment 1), C/N=25(2) and C/N=30(3) the maximum NH3 emission rate of 287.12 mg·h-1, 249.62 mg·h-1, 254.55 mg·h-1, respectively. Among them, C/N=20(treatment 1) NH3 emission. In cow dung and straw compost, C/N=20(treatment 4), C/N=25 processing(5) and C/N=30(treatment 6) the maximum NH3 emission rate were 260.13 mg·h-1, 214.66 mg·h-1, 208.13 mg·h-1. Among them, C/N=20(treatment 4) NH3 emission rate is the largest. In pig manure and straw composting. C/N=20 handle(7), C/N=25(8) and C/N=30(treatment 9) maximum NH3 emission rate respectively for 249.22 mg·h-1, 210.65 mg·h-1, 208.46 mg·h-1. Among them, C/N=20(treatment 7) NH3 emission rate is the largest. Show that with the increase of compost NH3 emission rate of C/N decreases, loss reduction of N. The groups of the chicken manure, cow manure, pig manure and straw compost treatment variation of N2 O can be seen the N2 O emission peak occurred mainly in the high temperature phase of composting. Although N2 O different C/N emissions are different, but the difference was not significant emissions.6. The temperature changes of the 9 groups of several agricultural wastes in the groups were in line with the temperature rising stage, the high temperature stage, the cooling stage and the stable stage. Chicken manure and straw 3 treatment groups. C/N=25 treatment(2) and the maximum temperature of a high temperature is 60 DEG; cow dung and straw 3 treatment groups. C/N=20 treatment(treatment 4), the highest temperature in high temperature stage, 68.5 Deg. C; pig manure and straw group 3 treatment, C/N=25 processing(processing temperature of high temperature stage 8) highest for 59 DEG C treatment. This experiment 1 to 9 p H value of compost were eventually stabilized at 8.21, 8.15, 8.24, 8.29, 8.30, 8.35, 8.30, 8.32, 8.31. Chicken manure and straw compost treatments. C/N=20(treatment 1) p H value rise in the highest, biggest change; cow dung and straw compost treatments, C/N=20(treatment 4) p H rise highest, biggest change; although pig manure and straw compost treatments. C/N=30 treatment p H value rise in the highest, the greatest change, but the difference with the other 2 groups is very small. The test group 9, the final EC value except chicken manure and straw compost C/N=20(treatment 1) EC Value of 2216μs·cm-1, pig manure and straw compost C/N=20(7) EC value is 2512μs·cm-1 outside, other treatments were between the 900~2000μs·cm-1, suitable for healthy crop growth. The seed germination rate index(GI) in addition to chicken manure and straw compost C/N=20(treatment 1) and chicken manure and straw compost C/N=25(2) than the other 7 groups of the final compost product GI 80% can be toxic to plants that. |
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