腐熟污泥施用对土壤有机-无机碳组分的影响

Effects of Agricultural Application of Composted Sludge on Organic-Inorganic Carbon Components

为探明腐熟污泥施用对两种不同酸碱性土壤有机碳、无机碳组分的影响,明确无机碳与有机碳及土壤酸碱性的关系,通过连续两年的盆栽试验,开展小麦玉米轮作模式下碱性壤土和酸性砂土污泥农用的研究。结果表明:添加腐熟污泥后,随污泥添加量的增加,两种土壤的有机碳(SOC)、易氧化有机碳(ROC)、可溶性有机碳(DOC)和腐殖质碳(HSC)等有机碳组分含量呈增加趋势。与对照(CK)相比,当污泥添加量为75 t/hm^2时,酸性砂土有机碳组分SOC、ROC、DOC、HSC含量分别增加了82.39%、25.62%、158.33%和30.77%(P<0.05);在碱性壤土中,上述有机碳组分分别增加了84.36%、49.26%、340.00%和354.90%(P<0.05),且两种土壤中各有机碳组分之间呈现极显著的正相关关系(P<0.01)。施用污泥降低了碱性壤土中ROC的分配比例(污泥施用量为3.75 t/hm^2时除外),但增加了DOC和HSC的分配比例;污泥农用降低了酸性砂土ROC和HSC的分配比例,但增加了DOC的分配比例。在碱性壤土中污泥农用降低了土壤无机碳(SIC)、活性无机碳(AIC)含量,同时土壤pH值降低;而在酸性砂土中污泥农用,土壤的SIC、AIC含量增加,同时土壤pH值增大;两种土壤的SIC和pH值之间均呈现极显著的正相关关系(P<0.01)。本研究可为不同酸碱性土壤碳库质量管理提供科学依据。

The agricultural use of composted sludge is an effective way to solve the problem of sludge recycling.Because sludge is rich in organic matter,agricultural use of sludge will affect the quality of soil carbon pool.In order to clarify the effects of sludge application on carbon components of two kinds of soils with different pH values,the effect of sludgeapplication on soil organic,inorganic carbon components and soil acidity were determined,and the relationship between soil inorganic carbon and organic carbon and soil pH value was explored.Under the wheat-maize rotation mode,two consecutive years experiment was carried out,four sludge addition amounts were 3.75 t/hm^2,7.5 t/hm^2,37.5 t/hm^2 and 75 t/hm^2,respectively,and one blank control was provided,which were marked as H1,H2,H3,H4 and CK,respectively.The main conclusions were as follows:the organic carbon components content such as soil organic carbon(SOC),readily oxidizable carbon(ROC),dissolved organic carbon(DOC)and humus carbon(HSC)were increased with the increase of sludge addition.Compared with CK,the SOC,ROC,DOC and HSC of acidic sandy soil were increased by 82.39%,25.62%,158.33%and 30.77%,respectively,when the sludge addition was 75 t/hm^2(P<0.05);the corresponding values were 84.36%,49.26%,340.00%and 354.90%in alkaline loam(P<0.05),and there was a very significant positive correlation among the organic carbon components in two kinds of soils(P<0.01).The application of sludge reduced the ROC distribution ratio(except when the amount of sludge was 3.75 t/hm^2),but increased the distribution ratio of DOC and HSC.However,the proportion of ROC and HSC was decreased,but the proportion of DOC was increased in acidic sandy soil.In addition,the content of soil inorganic carbon(SIC),active inorganic carbon(AIC)and pH value in alkaline loam were reduced due to application of sludge,and the pH value of soil was also reduced;however,AIC and pH value were increased in acidic sandy soil.There was a significant positive correlation between SIC and pH value of two kinds of soils(P<0.01).It can be concluded that application of composted sludge can produce different carbon effects on different acid-base soils.Therefore,sludge can be used in production practice to cultivate fertilizer or regulate the change of carbon pool quality in soil,and the acidification phenomenon of acid soil can be changed by adding composted sludge.