Effects Of Biogas Slurry And Biochar On Soil Carbon,Nitrogen And Heavy Mental In A Poplar Plantation In A Coastal Area,China

With the global crisis of energy and eco-environment,effective utilization of resources has become an essential issue.Biogas slurry provids abundant available nutrients while biochar is used for the improvement of soil properties.The experiment was conducted to focus on the effects of biogas slurry and biochar on soil carbon,nitrogen and heavy metals.We set four concentrations of biogas slurry as 0 CK),125?L?,250?M?,375 m3?H?per hectare,and four concentrations of biochar as 0?B0?,40?B1?,80?B2?,120 t?B3?per hectare,through randomized blocks design in a poplar plantation in a coastal area,Dongtai forest farm in Jiangsu province.The main results are shown as follow:?1?Biogas slurry supplied available nutrients to soil: the concentration of NO₃^--N,NH₄⁺-N,DOC,DON increased at all treatment modes,of which the maximum increment of DON was at M treatment mode while others were at H treatment mode.?2?Biogas slurry promotes nitrification in the soil to release H+,decreasing soil pH?with original pH of 8.6?.Meanwhile,it decreased the ratio of soil carbon to soil nitrogen?C/N?and the concentration of the soil MBC and SOC.The trend of these changes showed that the higher the concentration of biogas slurry was applyed to soil,the lower the concentrations of MBC,SOC and C/N were.Soil MBN was on the contrary.?3?Using biochar?made by polar wood at 600??only decreased soil pH?with original pH of 8.6?and soil MBC.It increased the concentration of NH₄⁺-N,NO₃^--N and MBN.?4?Biochar increased pH and decresed the concentration of NH₄⁺-N in the soil with biogas slurry treatment through cation exchange mechanism.It also increased C/N,SOC and MBC,while MBN decreased.?5?Taking high concentration of biogas slurry irrigation may result in nitrogen leaching,which could be eased by biochar.?6?Biogas slurry increased the concentration of Cr and Cu in the soil.It also increased the concentration of Zn in the soil layer of 10-25 cm.Biogas made that Cr enriched in the soil layer of0-10 cm while Cu,Pb and Zn had a infiltrating trend.Biochar decreased the concentration of Cr,Cu and Pb.It exist the fact that using biogas slurry and biochar at the same time inspired the concentration of heavy mental.In a word,biogas slurry,as one of first-class organic fertilizer,supplied a mass of available nutrients to soil.Particularly,high concentration of biogas slurry irrigation may result in nitrogen leaching,which could be eased by biochar yet.Using biogas slurry only increased the concentration of heavy mental in the soil,e.g.Cr,Cu.etc.On the contrary,using biochar only decreased it.It exist the fact that using biogas slurry and biochar at the same time inspired the concentration of heavy mental.