不同碳氮比下秸秆腐解与养分释放的动力学特征  

Dynamics Characteristic of Straw Decomposition and Nutrient Release Under Different C/N Ratio

作　　者：李然 徐明岗 孙楠[2] 王晋峰[1] 王斐 李建华[1] LI Ran;XU MingGang;SUN Nan;WANG JinFeng;WANG Fei;LI JianHua(Institute of Eco-Environment and Industrial Technology,Shanxi Agricultural University/Shanxi Province Key Laboratory of Soil Environment and Nutrient Resources,Taiyuan 030031;Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences/State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China/Key Laboratory of Arable Land Quality Monitoring and Evaluation,Ministry of Agriculture and Rural Affairs,Beijing 100081)

机构地区：[1]山西农业大学生态环境产业技术研究院/土壤环境与养分资源山西省重点实验室,太原030031 [2]中国农业科学院农业资源与农业区划研究所/北方干旱半干旱耕地高效利用全国重点实验室/农业农村部耕地质量监测与评价重点实验室,北京100081

出　　处：《中国农业科学》2023年第11期2118-2128,共11页Scientia Agricultura Sinica

基　　金：国家自然科学基金联合基金项目(U1710255);山西省科技重大专项计划“揭榜挂帅”项目(202201140601028)。

摘　　要：【目的】研究不同碳氮比下秸秆腐解和养分释放的动力学特征及其影响因素,为秸秆资源充分利用和煤矿区复垦耕地质量提升提供理论依据。【方法】依托山西煤矿复垦试验基地,开展大田填埋试验。供试玉米和小麦秸秆烘干过2 mm筛,通过添加尿素将玉米和小麦秸秆C/N比分别调节为25和10,以不添加尿素的秸秆(其C/N比分别为52和74)为对照,秸秆均按有机碳8 g称取后混匀,装于尼龙网袋(0.38μm孔径)内,水平埋入试验基地15 cm深的土壤中。在埋入土壤后的第12、23、55、218、281、365天采集尼龙袋内样品,分析玉米和小麦秸秆的干物质残留量、养分(碳、氮、磷和钾)释放的动态变化。【结果】前55 d,添加氮肥加快了玉米秸秆的腐解,以C/N比为25时腐解效果最佳。添加氮肥加快了小麦秸秆的腐解,以C/N比为10时腐解效果最佳。氮的添加可以显著促进前55 d玉米秸秆碳、磷的释放;氮的添加可以显著加快小麦秸秆碳、氮和磷的释放,对小麦秸秆中钾释放的促进作用不显著。小麦和玉米秸秆腐解及氮钾释放的一级动力学方程用积温拟合优于用时间拟合,秸秆磷的释放不适用衰减指数方程拟合。当积温为年积温(4 600℃)时,小麦和玉米秸秆碳、氮、磷和钾释放率的平均值分别为49.2%、39.5%、40.8%和90.3%;当累积积温达到1 125℃时,秸秆钾素释放85%以上。秸秆的腐解主要受温度、有机碳、木质素和半纤维素影响。【结论】施氮能加快玉米秸秆前期的腐解和碳、磷的释放,可以显著加快小麦秸秆的腐解和碳、氮、磷的释放。用温度拟合的方程比时间方程更能反映秸秆的腐解和氮钾释放过程。秸秆腐解主要受土壤温度,秸秆中有机碳、木质素和半纤维素含量的影响。因此,应结合煤矿区的水热条件,进行实时实地秸秆还田并配施适量的尿素,以提高复垦土壤的氮磷钾含量。【Objective】The decomposition,nutrient release characteristics and driving factors of straw under different C/N ratio were studied based on coal mining area,so as to provide as theoretical basis for the full utilization of straw resources and reclaimed soil fertility improvement.【Method】Air-dried maize straw and wheat straw were cut into 2 mm pieces and were selected for decomposition experiment of a coal mining reclamation area in Shanxi Province.Two C/N ratio levels of 25 and 10 were designed in maize straw and wheat straw by supplementing urea,taking no nitrogen application that C/N ratio levels was 52 and 74 as the control.All the straws(8 g in organic carbon)were put into a nylon mesh bag(0.38μm aperture),and horizontally buried into 15 cm deep of soil.On the 12,23,55,218,281 and 365 days after buried,samples were collected from the bags to analyze the dynamic of the dry matter residue and nutrient(carbon,nitrogen,phosphorus and potassium).【Result】During the first 55 days,the adjusting the C/N on 25 with the application N was the best way to accelerate the decomposition of maize straw.Meanwhile,the adjusting the C/N on 10 was the best way to accelerate the decomposition of wheat straw.Application N could significantly promote the release of carbon and phosphorus from maize straw during the first 55 days.Application N could significantly accelerate the release of carbon,nitrogen and phosphorus from wheat straw,but had no significant effect on the release of potassium.The thermal equation of straw decomposition and nitrogen and potassium release was better than the temporal equation,and phosphorus release from straw was not suitable for the exponential decay equation.When the accumulated temperature was 4600℃,the average release rates of carbon,nitrogen,phosphorus and potassium from straw were 49.2%,39.5%,40.8%and 90.3%,respectively;When the accumulated temperature reached 1125℃,more than 85%the potassium of straw was released.The decomposition of straw was mainly influenced by the temperature,

关 键 词：C/N比 秸秆 腐解 养分释放 动力学方程 煤矿复垦区 

分 类 号：S141.4[农业科学—肥料学]