Effect Of Fecal Biochar On Vegetable Growth And Heavy Matal Transport

With the development of livestock and poultry industry in China,more and more livestock manure needs to be treated.Livestock manure can be used as an excellent source of organic fertilizer.However,due to the influence of modern feeding methods,the content of heavy metals in livestock manure is generally high.The traditional composting treatment in the field will inevitably BRing potential risk of heavy metal pollution.Biochar is a new effective method for rapid resource disposal of organic waste.After biochar treatment,it is an important prerequisite for the effective application of livestock manure as crop nutrition improver whether it can maintain the supply of mineral elements while effectively fixing heavy metals and reducing the risk of heavy metal pollution.At present,there is no clear conclusion about the agricultural safety of livestock manure biochar.Therefore,this study mainly explored the effects of pig manure biochar on vegetable growth and heavy metal transport in the application process.In order to ensure the safety of manure biochar,we further discussed the earthworm treated manure biochar as a contrast,To explore the effect changes of fecal biochar after earthworm strengthening,in order to provide a new method for the resource utilization and safe use of livestock manure.The yield of biochar decreased with the increase of pyrolysis temperature,but the total pore volume increased with the increase of pyrolysis temperature,and the adsorption efficiency was stronger.At the same pyrolysis temperature,the total control volume of earthworm manure biochar was larger than that of pig manure biochar.The C,H and N on the surface of biochar also decrease with the increase of pyrolysis temperature,but the C/N ratio increases with the increase of pyrolysis temperature,which indicates that high temperature makes biochar more stable.Compared with pig manure,the contents of heavy metals in earthworm manure decreased significantly.The contents of Cd,Cr,Cu and Zn decreased by 42.60%,40.64%,49.49% and 54.85% respectively,which indicated that earthworm had a good strengthening effect.The contents of Cr,Cu and Zn in fecal biochar increased with the increase of pyrolysis temperature.The effect of biochar on Rape(BRassica rapa,BR),Cherry Radish(Raphanus sativus,RS)and chrysanthemum coronarium(Chrysanthemum coronarium,CC)seeds showed the phenomenon of low promotion and high inhibition.Generally,the germination potential and germination rate reached the maximum under the condition of adding 20%,and the germination performance of the earthworm manure biochar group was better.The addition of biochar could increase the biomass of rape and Cherry Radish,but for chrysanthemum,the addition of pig manure biochar could inhibit the growth and reduce the biomass,while earthworm manure could promote the growth of chrysanthemum,which showed the best performance at 500℃ and 700℃,increased by11.37% and 29.73% respectively compared with pig manure biochar.In spatial configuration,the root shoot ratio of three vegetables increased with the increase of pyrolysis temperature,but the root shoot ratio of earthworm manure biochar group was smaller than that of pig manure biochar group at the same pyrolysis temperature.The maximum photosynthetic rate of three vegetables was significantly higher than that of pig manure biochar.The content of superoxide dismutase in rape and radish decreased with the increase of biochar pyrolysis temperature,but the earthworm manure biochar group was significantly higher than the pig manure biochar group,and its adaptability to stress was also stronger.For rape and radish,the contents of Zn,Cu and Cd in earthworm manure biochar group were less than those in pig manure biochar group,while the concentrations of Cu,Cr and Zn in chrysanthemum were less affected by biochar types.In addition,the pyrolysis temperature of biochar also has a significant effect on the transport process of heavy metals in plants.Whether it is pig manure biochar or earthworm manure biochar,the content of heavy metals in vegetables is relatively small when the pyrolysis temperature is 500℃ and 700℃.Considering the low production cost,yield,quality and other factors in the practical application process,500℃ is the best pyrolysis condition.In conclusion,the effects of pig manure biochar and earthworm manure biochar on the transport mechanism of heavy metals in the three crops showed great interspecific differences,which was related to the different tolerance of plants to different kinds of heavy metals and heavy metals.Pig manure derived earthworm manure biochar was not only superior to pig manure biochar in physical and chemical properties and heavy metal species and content,but also could alleviate the pollution of rape,rape and other crops The toxic effects of heavy metals on Chrysanthemum and Cherry Radish regulate the transport of heavy metals in plants.However,comprehensive analysis of biomass,plant growth,root shoot ratio and heavy metal content showed that the effect of earthworm manure biochar was better than that of pig manure biochar,and it was more suitable as a soil regulator for increasing yield and income.