玉米秸秆碳形态对植烟土壤有机碳及土壤综合肥力的快速提升效应

Rapid Improvement of Maize Straw Carbon Form on Soil Organic Carbon and Comprehensive Fertility in Tobacco Planting Soil

为探究不同玉米秸秆碳形态的增碳培肥效果,在烟田上建立原位土柱培养试验,分析不添加秸秆碳(CK)、添加常规秸秆(RS)、腐熟秸秆(DS)以及秸秆生物炭(BC)4个处理下耕层(0~20 cm)土壤有机碳组分和结构、理化性质及酶活性等指标。结果表明,与不添加秸秆碳相比,3种秸秆碳形态显著提高土壤总有机碳(TOC)和微生物量碳(MBC)含量。与不添加秸秆碳相比,常规秸秆和腐熟秸秆处理显著提高了土壤可溶性有机碳(DOC)含量,而秸秆生物炭处理显著增加了颗粒有机碳(POC)含量(42.40%)。3种秸秆碳形态均提升微生物量碳/有机碳,这表明了秸秆碳投入可促进土壤有机碳周转。采用^(13)C核磁共振波谱技术(NMR)分析土壤有机碳官能团结构,结果表明,常规秸秆、腐熟秸秆处理增加了土壤烷氧碳(O-Alkyl-C)和羰基碳(Carbonyl-C)(易降解碳组分),而秸秆生物炭则增加了烷基碳(Alkyl-C)(难降解碳组分)、烷基碳/烷氧碳(A/O-A)和疏水碳/亲水碳(Hydrophobic-C/Hydrophilic-C)。不同形态的秸秆碳对土壤养分及酶活性具有差异性,秸秆生物炭处理显著提升速效钾(AK)、铵态氮(AN)和硝态氮(NN)含量,分别为65.72%,19.93%,5.77%,常规秸秆和秸秆生物炭处理可显著提高蔗糖酶(Su)和脲酶(Ur)的活性,而磷酸酶(Ps)活性均随3种形态秸秆碳添加而提升。冗余分析表明,碳氮比(C/N)、纤维素酶(Ce)和全氮(TN)是影响土壤有机碳含量差异的主要因子;纤维素酶、pH值和速效钾是影响有机碳结构差异的主要因子。综上,施用秸秆生物炭在短期内具有提升有机碳含量及稳定性、养分含量和酶活性的显著优势,且土壤综合肥力评价中也以秸秆生物炭处理的得分最高(0.57),表明添加玉米秸秆生物炭是能够快速提升植烟土壤有机碳水平并改善土壤肥力的有效措施。

To investigate the effects of different maize straw carbon addition on soil organic carbon and fertilizer improvement,it focused on an in-situ soil column incubation experiment was established on tobacco fields.Four treatments were set,including none straw addition(CK),conventional straw(RS),decomposed straw(DS)and straw biochar(BC).The organic carbon components and structure,soil physical and chemical properties,and enzyme activities of the 0-20 cm soil layer of tobacco field treaded by the four treatments were characterized and analyzed.One-year incubation results showed that:Compared with none straw addition,the three forms of straw carbon addition all significantly increased the content of total organic carbon(TOC)and microbial biomass carbon(MBC)in the soil.Compared with none straw addition,treatments of conventional straw and decomposed straw significantly increased soil dissolved organic carbon(DOC)content,while straw biochar treatment significantly increased particulate organic carbon(POC)content(42.40%).The three forms of straw carbon addition all significantly increased the microbial biomass carbon/total organic carbon ratio and promoted the turnover of soil organic carbon.The functional group structure of SOC was analyzed by ^(13)C nuclear magnetic resonance.The results indicated that conventional straw and decomposed straw treatment increased the relative content of Alkoxy carbon(O-Alkyl-C)and Carbonyl carbon(Carbonyl-C)(labile carbon component),while straw biochar treatment increased Alkyl carbon(Alkyl-C)(recalcitrant carbon component),Alkyl carbon/Alkoxy carbon(A/OA)and Hydrophobic-C/Hydrophilic-C(Hydrophobic-C/Hydrophilic-C).Different forms of straw carbon had significantly different effects on soil nutrients and enzyme activities,straw biochar treatment significantly increased by 65.72%,19.93%and 5.77%for the content of available potassium(AK),ammonium nitrogen(AN)and nitrate nitrogen(NN),respectively.Conventional straw and straw biochar treatments significantly increased the activities of sucrase(Su)and urease(Ur).The three forms of straw carbon all had a significant effect on the activity of phosphatase(Ps).Redundancy analysis showed that C/N ratio(C/N),cellulase(Ce)and total nitrogen(TN)were the main factors affecting the organic carbon content,while cellulase,pH,and available potassium were the main factors affecting the organic carbon structure.Overall,the application of maize straw biochar had significant advantages in improving organic carbon content and stability,nutrient content,and enzyme activity in a short term.In the comprehensive soil fertility evaluation,straw biochar had the highest score with 0.57.Maize straw biochar was an effective measure to improve the organic carbon level and soil fertility in the tobacco planting soil.