Effects Of Stover Thermal Transformation Products On Fertility Improvement And Organic Matter Characteristics Of Black Soil

In China,the annual output of stover is huge,and the total amount of stover used for fuel is about 88.9 million tons.After burning stover for power generation,a large number of stover ash and ash will be produced.These thermal conversion products are mostly used in chemical industry,construction and other industries,and they are rarely used in agricultural utilization.In order to make rational use of stover thermal conversion products and improve soil properties,pot experiments were conducted to study the effect of stover thermal conversion products on black soil under the same amount of C,so as to provide reference for the application of stover thermal conversion products in agriculture.Pot experiments were conducted for two consecutive years CK(control),CS(corn stover),HCS(humified stover),Bc(biochar),ASH(corn stover ash),CHZ(corn stover coarse ash)and XHZ(corn stover fine ash)were mixed with soil.The amount of corn stover was converted according to the total amount of returning to field,and the amount of other treatments was added according to the carbon amount of corn stover.The structure of HA was analyzed by Fourier transform infrared spectroscopy,element analyzer,differential thermal analysis and fluorescence spectroscopy.The results showed that:(1)After the stover and its heat conversion products returned to the field,all treatments promoted the growth of corn and increased the corn yield.Compared with CK,the plant height and yield of Bc treatment were the highest in two years,followed by stover ash treatment(ASH).(2)Compared with CK,Bc treatment significantly reduced soil compaction,increased soil nutrient content,and the alkali-hydrolyzable nitrogen,available phosphorus and available potassium increase by 16.49%～12.99%,32.80%～38.37% and 26.04%～34.78% respectively compared with CK.In the second year of pot experiment,compared with other treatments,Bc and ASH treatments had the largest increase in soil nutrients.(3)Bc treatment also significantly increased the content of soil SOC and humic acid(HA)and humin(HM),and increased the PQ value(the radio of HA proportion in ex-tractable humus),Bc treatment increased SOC the most,22.08% and 22.51%higher than CK treatment,followed by ASH treatment,which increased 17.10% and18.18% compared to CK.(4)Compared with CK,Bc treatment is conducive to improving the aromaticity of HA structure,increasing the thermal stability of HA and making the structure more stable,followed by ASH treatment;However,HCS and CS treatments are more conducive to improve ha activity,increase the aliphatic properties of HA molecules,and simplify the structure.(5)In conclusion,the application of biomass carbon is the best choice to improve corn yield and soil fertility and improve soil structure in a short time.The judgment and selection of long-term effect need to be carried out in the field for a long time and in-depth experiment and further study.