Study Of Greenhouse Gases Emission And Carbon Cycle From The Soil Under The Condition Of Several Agricultural Waste Returning To Field

Agricultural production has an important influence on the level of greenhouse gases in the atmosphere, which directly affects of global climate change. Fertilization is the essential means to increase agricultural production and economic benefits. It is also the significant emission source of greenhouse gases. Fertilizer and agricultural wastes are combined in proper ration in order to support resource utilization of agricultural wastes. It can reduce polluting emission and improve agricultural sustainable development capacity. During the growing season of maize, the static chamber technique is used. Under the condition of the same amount of NPK nutrition, combining straw, cow dung and fowl manure with fertilizer in proper ration returning to field. The influences of CO2, N2 O and CH4 emissions, soil carbon and plant carbon are studied in this paper. The conclusions are as follows:1 CO2 emission and seasons show a regularly change. Under the condition of the same amount nutrition(N 240kg/hm2, P2O5 100 kg/hm2, K2 O 120 kg/hm2).Single application of chemical fertilizer(treatment S1), 100% straw fertilizer pure N 215.62 kg/hm2(treatment S2), 50% cattle manure organic nitrogen application in the field with 50% nitrogen fertilizer(treatment S3) and 50% of organic chicken manure nitrogen application in the field with 50% nitrogen fertilizer(treatment S4) in June, July, August. The three months in the amount of CO2 emissions were accounted for the total emissions of respectively 83.74%、80.08%、78.90% and 78.78% in growth season. Cattle manure returning to field reduces the emission of CO2 in soil, 50% cattle manure organic nitrogen application in the field with 50% nitrogen fertilizer(treatment S3) led to the lowest average CO2 emission flux, up to 357.02 mg/(m2·h).2.N2 O emissions were significantly influenced by fertilization. N2 O emissions in all fertilization treatments are higher than CK treatment, and the difference was significant. There were also differences in N2 O emissions of all fertilization treatments. The average fluxes of N2 O emissions in chemical fertilizer(treatment S1), 100% straw fertilizer pure N 215.62 kg/hm2(treatment S2), 50% cattle manure organic nitrogen application in the field with 50% nitrogen fertilizer(treatment S3) and 50% of organic chicken manure nitrogen fertilizer nitrogen fertilizer was 50%(treatment S4) were respectively 153.21μg/(m2?h), 138.64μg/(m2?h), 137.19μg/(m2?h) and 135.80μg/(m2?h). The results showed that agricultural waste and fertilizer to field can reduce the emission of N2 O, and it was a significant difference with the application of single chemical fertilizer(treatment S1).3. The upland soil was an important sink of atmospheric CH4 absorption. All treatments showed absorption of CH4 during corn growth period. The average fluxes of CH4 emissions in CK, single application of chemical fertilizer(treatment S1) and 100% straw fertilizer pure N 215.62 kg/hm2(treatment S2), 50% cattle manure organic nitrogen application in the field with 50% nitrogen fertilizer(treatment S3) and 50% of organic chicken manure nitrogen application in the field with 50% nitrogen fertilizer(treatment S4) in the growth period were-34.55μg/(m2?h),-42.18μg/(m2?h),-24.60μg/(m2?h),-29.89μg/(m2?h) and-34.99μg/(m2?h). Compared with the 100% straw fertilizer pure N 215.62 kg/hm2(treatment S2), single chemical fertilizer(treatment S1) increased by 41.69% in absorption. Compared with50% cattle manure organic nitrogen application in the field with 50% nitrogen fertilizer(treatment S3), single chemical fertilizer(treatment S1) increased by 29.13% in absorption. Compared with 50% of organic chicken manure nitrogen fertilizer nitrogen fertilizer was 50%(treatment S4), single chemical fertilizer(treatment S1) increased by 19.42% in absorption. The results showed that in the same nutrient conditions of the nitrogen phosphorus and potassium, single application of chemical fertilizer(treatment S1) could absorb the maximum amount of atmospheric CH4, and it was significant difference between the other agricultural wastes.4. Agricultural waste and fertilizer to field could promote the accumulation of soil organic carbon. In the same nutrient conditions, the soil organic carbon content of single application of 100% straw fertilizer pure N 215.62 kg/hm2(treatment S2), 50% cattle manure organic nitrogen application in the field with 50% nitrogen fertilizer(treatment S3) and 50% of organic chicken manure nitrogen fertilizer nitrogen fertilizer was 50%(treatment S4) compared to before planting increased by 7.46%, 10.85% and 5.99%.100% of straw and fertilizer of pure N 215.62 kg/hm2(treatment S2),50% cattle manure organic nitrogen application in the field with 50% nitrogen fertilizer(treatment S3) and 50% of organic chicken manure nitrogen application in the field with 50% nitrogen fertilizer(treatment S4) the proportion of organic carbon inputs 3.88:1.86:1. The proportion of input organic matter in 50% cattle manure organic nitrogen application in the field with 50% nitrogen fertilizer(treatment S3) and 50% of organic chicken manure nitrogen application in the field with 50% nitrogen fertilizer(treatment S4) was consistent with the increase in the proportion of soil organic carbon after the autumn harvest.5.Carbon content between individual processing plant organs showed a balance b y different treatments. There was no significant difference. Plant carbon fixation was closely related to plant biomass. Plant carbon fixation increased with the increasing of biomass. In all treatments of CK, 50% chicken manure organic nitrogen combined ap plication of nitrogen fertilizer in field 50%(treatment S4) was the maximum biomass.So the 50% chicken manure organic nitrogen application in the field with 50% nitrog en fertilizer(treatment S4) carbon sequestration was also the largest, up to 147.59g/pl ant. The regional carbon sequestration amount for theory was the product of the multi ply unit plant carbon fixation and the planting density. Therefore, the carbon sequestra tion of 50% of organic chicken manure nitrogen application in the field with 50% nitr ogen fertilizer(treatment S4) was the highest, up to 9.59 t/hm2.6 The output of various fertilizer treatments is more than that of CK treatment. The output of agricultural wastes returned to field is more than that of applying chemical fertilizer. Compared with single chemical fertilizer(treatment S1), 50% cattle manure organic nitrogen application in the field with 50% nitrogen fertilizer(treatment S3),50% of organic chicken manure nitrogen fertilizer nitrogen fertilizer was 50%(treatment S4),the 100% straw fertilizer pure N 215.62 kg/hm2(treatment S2) increased by 5.70%, 4.80% and 4.30% respectively. The output of agricultural wastes returned to field is more than that of single chemical fertilizer(treatment S1). The output of 50% cattle manure organic nitrogen application in the field with 50% nitrogen fertilizer(treatment S3) is the most. Compared with single chemical fertilizer(treatment S1), volume variance reaches significant level.