| Recycling waste is conducive to the healthy development of ecology and the layout and scale of agricultural industry.At present,with the increasing number of crops and livestock and poultry breeding,how to deal with the waste brought by its planting and production scale has also become a top priority.The research shows that the biochar prepared from straw and branches can improve the maturity of the pile and reduce the emission of harmful gases.In addition,the mixed application of organic fertilizer and inorganic fertilizer produced by composting can also save planting costs and improve soil conditions.However,at present,there is little research on the fertilizer effect of organic fertilizer produced by branch biochar composting.In this paper,through the mixed composting of biochar prepared from pepper branches in Hancheng City and pig manure,the indexes of main substances in the composting process(temperature,moisture content,p H,conductivity,nitrous oxide,carbon dioxide,nitrogen content,organic matter content,ammonium nitrogen,nitrate nitrogen,seed germination index,etc.)are studied,The basic law of matter change and maturity degree of pig manure composting under different biochar addition and different carbon nitrogen ratio were revealed.The parameters of pig manure mixed composting were optimized by central composite experimental design.The optimal proportion of organic fertilizer and inorganic fertilizer is obtained by studying the effect of mixed fertilizer on the growth process of Chinese cabbage.The research results are as follows:(1)The effects of different biochar treatments(2.5%(T1),5%(T2)and 7.5%(T3)of dry weight of the reactor)on pig manure composting were studied.By controlling the carbon nitrogen ratio to 25:1,the changes of various physical and chemical indexes and the degree of maturity in the compost were observed and measured.The addition of biochar can improve the ventilation conditions of the reactor,increase the internal oxygen,promote the composting process and improve the maximum temperature that the reactor can reach,However,excessive biochar addition will also have an inhibitory effect on composting.For example,the temperature of T3 does not reach 50 ℃.When the amount of biochar was 5%,the seed germination index reached 94,the temperature reached 50 ℃ on the fifth day and lasted for3 days,the moisture content was 72%,and the data indexes such as greenhouse gas emission were better than the pile with the amount of biochar of 2.5% and 7.5%.(2)The effects of different carbon nitrogen ratios(20:1(T4),25:1(T5))and 30:1(T6))on pig manure composting were studied.By controlling the addition of biochar to 5% of the dry weight of the compost,the changes of various physical and chemical indexes and the degree of maturity in the compost were observed and measured.It was found that when the C/ N of the compost was 20,the temperature of the compost was slow and reached 50 ℃ on the 11 th day.When the C / N was 30,the reactor reached 50 ℃ on the fourth day.However,when the carbon nitrogen ratio was 25,the seed germination index was higher than T4 and T6,the temperature lasted for more than 3 days at 50 ℃,the moisture content was also more stable than T4 and T6,the conductivity and p H were 3.14 and 8.01 respectively,and the gas emission and other indicators were also better than T4 and T6.(3)The process parameters of composting were optimized by response surface method.Taking C / N and biochar addition as independent variables and seed germination index as dependent variables,the optimal process conditions were obtained through model optimization.With the increase of biochar and C / N,the seed germination index increased first and then decreased;There is interaction between biochar and C / n.When the optimal composting process was C / N 26.025:1 and the amount of biochar was 5.305%,the maximum seed germination index was 94%.During this period,the internal microbial activity is also the most vigorous.The temperature can reach 50 ℃ and last for more than 3 days,and the maturity is the best.(4)The best compost and chemical fertilizer were mixed and divided into five groups:pure inorganic fertilizer(T1),nitrogen content in inorganic fertilizer: organic fertilizer nitrogen content 1:3(T2);2:2(T3);3: 1(T4)and pure organic fertilizer(T5).It was found that the total length and single plant quality of the treatment of mixed application of organic fertilizer and inorganic fertilizer at the end of potting were higher than T1 and T5 with simple addition of organic fertilizer.Therefore,the mixed application of organic fertilizer and inorganic fertilizer can make Chinese cabbage thrive and improve the content of soil nutrients.At the end of the five treatments,the highest vitamin C content of T3 was 86.21mg/kg,and the weight of pakchoi was large,reaching 26.53 g,significantly higher than T4(P < 0.05).The leaf area and leaf length were also large,with an average height of about 55.17 cm.At the end of potting,there was no significant difference between T3 length and T4(P > 0.05),so T3 was the optimal group. |
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