| The global climate change has become the focus of global concern, all countries should work together to address climate change, to promote green, low carbon development which has become mainstream in today’s world. Farmland ecosystem as an important source of emissions of greenhouse gases, more and more attentions were paid by governments and scientists. Biochar in agriculture has been internationally recognized to control land degradation and to ensure food production, as well as an important way to address climate change.1. A field experiment was conducted to investigate the effect of biochar on maize and winter wheat yield in a calcareous loamy soil poor in organic carbon from Henan, central great plain, China. Biochar was applied at rates of0,20,40t hm"2with or without N fertilization. Results showed that biochar amendments significantly increased maize production. Maize yield was increased by18.2%and11.6%with N fertilization, and by15.8%and7.3%without N fertilization under biochar amendment at20t hm-2and40t hm-2, respectively. Biochar amendments had no effect on wheat yield.In maize season, soil organic carbon was increased by25.0%and42.2%, but soil bulk density was reduced0.13and0.17g cm-3with fertilization under biochar amendment at20t hm-2and40t hm"2, respectively. However, soil pH value and soil total nitrogen had no differences as compared to the control. In treatments without N fertilization, SOC was found to increase by57.8%and44.0%, total N was aslo increased by24.1%and31.0%under biochar amendment at40t hm"2(C2N0) and20t hm-2(C1N0) as compared to no biochar treatment (C0N0), Biochar amendment at40t hm-2caused a significant decrease in soil bulk density by0.17g cm-3and by0.28g cm-3with and without N fertilization. Biochar amendments had no significant effect on NH+-N and NO3--N. The agronomic N use efficiency (AEN) was increased from1.25kg kg-1with no biochar to2.28kg kg-1with biochar at40t hm-2.In the wheat season, biochar amendments had no significant effect on total soil nitrogen. Biochar amendments increased soil organic carbon, soil available P and K content, but reduced soil bulk density in the wheat reason. Soil organic carbon was increased by22.3%and15.8%with biochar as compared to control. Soil bulk density was decreased by0.08-0.1g cm"3, which showed that the effect on the soil after wheat yield was thinner that in the maize season. Soil available phosphorus was increased by31.9%under biochar amendment at201hm-2, while available potassium were increased by47.8%under biochar amendment at40t hm-2, we can conluded that biochar amendments increased soil nutrient content. Biochar applied to the dry croplands can provide moisture and water for plant which grew in drought conditions.2. This paper was studied to access the effect of biochar on green house gases (GHG). Results showed that N2O emission was increased with fertilization and raining, With N fertilization, biochar amendments resulted in a reduction in N2O emission by10.7%and by71.8%under C1N1and C2N1as compared to C0N1. However, there were no significant differences observed between biochar treatments without N fertilization. Results for CH4emission rates showed a small but insignificant "sink effect" in the dry cropland over the WMGS. While there was no difference in total CO2emission between treatments of C1N0and C0N0, total CO2emission was increased by12%under C2N0compared to under C0N0. In the wheat season, addition of biochar amendments resulted in a reduction in N2O emission by34.88%and34.3%under C1N1and C2N1as compared to C0N1. However, there were no significant differences observed between biochar treatments. Biochar amendments had no significant effect on total CH4and N2O emissions.There was a significant decrease in the overall total GWP and GHGI for the CH4and N2O when calculated over a100-year time frame. GWP was decreased by9.7%and41.5%, while GHGI was reduced by23.8%and46.7%with N fertilization under biochar amendments at20t hm-2and40t hm"2compared to control, respectively. However, there was no significant effect on GWP and GHGI. In the wheat season, GWP was decreased by35.3%and34.6%, while GHGI was reduced by34.0%and36.6%compared to C0N1, respectively. Biochar have a significant effect in reducing N2O emissions from dry lands and reducing nitrogen fertilizer application and greenhouse gases emissions from the process of nitrogen fertilizer production, it promote the application of biochar and the development of sustainable ecological agriculture.3. In this paper, a field experiment of amendment of biochar pig compost (BPC) in conjunction with pyroligneous solution (PS) from crop straw pyrolysis on soil fertility and wheat yield in a moderately salt stressed Entisol from the Central Great Plain of North China. The soil was amended with the BPC at12t hm-2following an initial treatments treated with diluted PS solution at0.15t hm-21week in advance, fertilization was added, wheat yield reached to450kg mu-1. Physical and chemical analysis showed significant effect on decreasing soil salinity by40%, soil pH by0.3and soil bulk density (BD) by0.1g cm-3decreased from1.33g cm-3to1.21g cm-3, exerting a much greater extent than the conventional farming. Plant tissue analysis revealed a greatly enhanced N translocation from shoot to grain under BPC-PS over the control and the conventional reclamation, thus increasing the fertilized nutrient use efficiency. The agronomic N use efficiency was increased by25%, to provide the nutrient to plant. Therefore, amendment of biochar compost in conjunction with pyroligneous solution would offer an effective measure to alleviate the salt stress and improving crop productivity in salt affected croplands. Further studies are needed for understanding the mechanism behind.In summary, results showed that biochar from crop straw was broadcasted in the soil, not only to deal with straw and other waste, but also to reduce soil greenhouse gas emissions, to improve the dry land salinity soil, to increase soil moisture and to make full use of nitrogen fertilizer. |
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