| Biochar(Bc) is a kind of black carbon(BC), the research on biochar application in agriculture mostly concentrated on its effects on physicochemical properties, but there are little studies about the effects of Bc application on the content and structural characteristics of black carbon of black soil, the composition of humus,the structural characteristics of humic acid(HA)and soil and crop growth. This experiment was carried out in pot trial, culture experiment and field experiment to solve all these problems. Pot trial was set 4 treatments, the applied amount are equivalent to CK, 6t·hm-2,12t·hm-2 and 24 t·hm-2, respectively. Culture experiment was set 3treatments, the applied amount are equivalent to CK, 6t·hm-2and 12t·hm-2, respectively. Field experiment was set 2 treatments, the applied amount are equivalent to CK and 48t·hm-2,respectively. The method Wolbach-Anders were adopted to extract the black carbon, and the structural changes of BC were indicated by the elemental composition, FTIR(Fourier Transform infrared spectroscopy) and thermogravimetric analysis. The modified method of humic substance composition and the method recommend by IHSS were adopted to extract the humic components and purify the HA sample, the thermal oxidation of K2Cr2O7 and TOC analyzer were applied in analyzing the C contents of WSS, FA, HA and Hu, and the structural changes of HA were indicated from the elemental composition and FTIR. The experiment results showed : 1).The application of Bc can improve the content of SOC significantly; 2)Bc application can change the composition of soil humus, increase the organic carbon content of Hu, HA and WSS, lowered the organic carbon content of FA, improve the PQ value; 3) The elements analysis and FTIR showed that Bc application can enhance the stability of HA,improve the degree of aliphatic and aromaticity, lowered degree of oxidation; 4) Biochar application can improve the BC content of black carbon; 5) Corn stover biochar application can enhance the stability of BC structure, lowered the soil BC aliphatic and oxidation degree,improved soil BC degree of condensation, aromaticity, and corn stover biochar can improve BC’s thermal stability; 6) Corn stover biochar application can improve the p H and EC value of black soil, improve the content of available nitrogen and available phosphorus;7) Corn stover biochar application can improve the corn yield, and plant height, stem diameter, panicle length,panicle weight and rod weight.These also showed that Bc application can improve the soil fertility and has important value on the promoting agriculture eco-development. |
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