添加不同来源生物质炭对暗棕壤腐殖质组成和胡敏酸结构特征的影响

Effect in Humus Composition and Humic Acid Structure Characteristic by Adding Different Sources of Biochars to Dark Brown Soil

为了研究暗棕壤添加不同来源的生物质炭对腐殖质组成和胡敏酸结构特征的影响,选用玉米秸秆生物质炭(JG-Bc)、杨木生物质炭(YM-Bc)和毛竹生物质炭(MZ-Bc)进行培养试验,生物质炭(Bc)添加量为10.6 g/kg(相当于24 t/hm^2)。采用腐殖质组成修改法测定胡敏酸(HA)、富里酸(FA)和胡敏素(Hu)的含量;用国际腐殖质协会(IHSS)推荐的方法提取和纯化HA样品,并研究了胡敏酸的元素组成、红外光谱和热力学性质。结果表明:培养90 d后,添加生物质炭处理显著提高了土壤有机碳(SOC)和腐殖质各组分含量。SOC的增加主要体现在Hu上,由ck的8.40 g/kg增加到16.45~18.04 g/kg。可提取腐殖质总量虽然变化不大,但HA比例增加,PQ值由ck的54.71%上升到75.24%~82.50%。添加Bc不仅提高了HA的含量和比例,同时也影响到HA的结构特征,表现为HA的Δlog K、H/C摩尔比、O/C摩尔比降低;碳元素含量和分子缩合度增加,脂族链烃比例增加,促进HA结构趋于复杂化;HA的高温/中温放热和失重比值增加,热稳定性提高。不同处理之间作用大小顺序:毛竹Bc>杨木Bc>玉米秸秆Bc。该研究可为分析不同来源的生物质炭与腐殖质的关系及增加土壤有机质积累提供理论依据。

In order to study the effects of different sources of biochars on the composition of humic substance and the structural characteristics of humic acid in dark brown soil,a culture experiment was conducted with corn straw biochar(JG-Bc),poplar biochar(YM-Bc)and bamboo biochar(MZ-Bc),and the amount of biochars added is 10.6 g/kg(equivalent to 24 t/hm^2).The contents of humic acid(HA),fulvic acid(FA)and humin(Hu)were measured by the modified humic composition method.The humic acid(HA)samples were extracted and purified by the method recommended by IHSS,and the elemental composition,FTIR and thermal properties of humic acid were studied.The results showed that after 90 days of culture,the contents of soil organic carbon(SOC)and humus were significantly increased by adding biochars.The increase of SOC was mainly reflected in the increase of Hu,from 8.40 g/kg of ck to 16.45 g/kg-18.04 g/kg.Although the total amount of extracted humus did not change significantly,the proportion of HA increased,and PQ increased from 54.71%of ck to 75.24%-82.50%.The addition of Bc not only increased the content and proportion of HA,but also affected the structure of HA,showing a decrease inΔlogK,H/C molar ratio and O/C molar ratio of HA;And the structure of HA was promoted to be complex by the increase of carbon content and molecular condensation,and the increase of aliphatic chain ratio and chain length;HA high/medium temperature exothermic and weight loss ratio increased,and thermal stability improved.The order of action between different processes is:Bamboo Bc>poplar Bc>corn stalk Bc.The results of the study provide a theoretical basis for analyzing the relationship between biochars from different sources and humus and increasing soil organic matter accumulation.