摘要
【目的】研究增温对不同作物秸秆在土壤中分解速率的影响。【方法】于2019年11月至2020年10月进行两个生长季的田间填埋试验,观测增温和对照处理下玉米、红薯、大豆秸秆在夏熟作物生长季的分解率以及冬小麦、大蒜、油菜秸秆在秋熟作物生长季的分解率,并以秸秆初始碳含量、氮含量、碳氮比、木质素含量模拟不同处理下不同作物秸秆的分解速率系数。利用模型模拟得到的分解速率系数k值进一步模拟增温和对照处理下不同作物在填埋后不同天数的剩余秸秆质量,将剩余秸秆质量的模拟值与观测值进行回归分析以评估模型模拟效果。【结果】增温对玉米、红薯、冬小麦秸秆初期分解率具有显著(P<0.05)促进作用,而对这3种作物秸秆在其他时间段的分解率无显著影响。增温对油菜秸秆在整个生长季的分解率具有显著(P=0.029)促进作用。增温对大豆、大蒜秸秆在整个生长季的分解率无显著(P>0.05)影响。增温对6种作物秸秆分解速率系数均无显著(P>0.05)影响,而不同作物秸秆分解速率系数之间存在显著(P<0.05)差异。无论是对照还是增温条件下大蒜秸秆分解速率系数均最高,而大豆秸秆分解速率系数最低,大蒜秸秆分解速率系数超过大豆秸秆2倍。以不同作物秸秆碳含量(C)、氮含量(N)、碳氮比(C/N)、木质素含量(L)为因变量,采用多元线性回归,可得不同处理下不同作物秸秆分解速率系数的模拟方程(k=−1.073C+7.315N+0.223C/N−0.004L+33.900),该方程可模拟92.1%(R^(2)=0.921,P<0.001)的秸秆分解速率变异,描述模拟值和观测值之间关系的线性回归方程斜率非常接近1∶1线。利用模拟得到的秸秆分解速率系数k值对本研究填埋试验中观测的不同填埋天数后的剩余秸秆质量进行验证分析,可见增温和对照处理下不同作物剩余秸秆质量模拟值和观测值具有非常好的一致性(R^(2)=0.922,P<0.001),表明该模拟方程可有效模拟秸秆分解动态。【结论】增温比对照显著增加了玉米、红薯和冬小麦秸秆在分解初期的分解率,并增加了油菜秸秆在整个生长季的分解率,但对大豆、大蒜秸秆在整个生长季的分解率没有显著影响。作物秸秆的分解速率系数可用秸秆碳氮含量、木质素含量以及碳氮比进行模拟,用分解速率系数的模拟方程可有效估算对照和增温处理下不同作物秸秆在填埋后不同天数的剩余秸秆质量。
【Objectives】This study aimed to investigate the effects of warming on the decomposition rates of different crop straws in soils.【Methods】A field embedding experiment was performed during the two growing seasons from November 2019 to October 2020.The decomposition percentages of the straw of maize,sweet potato and soybean during the summer crops growing season and the straw of winter wheat,garlic and rape during the autumn crops growing season were measured.The coefficients of decomposition rates were simulated with a function including the initial C,N,lignin content and C/N ratio of different crop straws.The modelled decomposition coefficient k value was further used to predict the residual straw mass of different crops after the different embedding days.The predicted and observed residual straw mass was analyzed using a linear regression to evaluate the modelling efficiency.【Results】Compared with control,warming significantly(P<0.05)increased the decomposition percentage of the straw of maize,sweet potato and winter wheat during the early decomposition period,but had no significant(P>0.05)effects on the decomposition percentage during other decomposition periods.Warming induced a significant(P<0.05)increase in the decomposition percentage of the straw of rape during the whole growing season.Warming had no significant(P>0.05)effects on the decomposition percentage of the straw of soybean and garlic during the whole growing season.Warming had no significant(P>0.05)effects on the coefficients of decomposition rates of the straw of the six crops.However,there were significant(P<0.05)differences in the coefficients of decomposition rates of the straw among the six crops.The decomposition coefficient was highest for the garlic straw and lowest for the soybean straw under both control and warming treatments.The decomposition coefficient of the garlic straw was twice times higher than that of soybean straw.Multiple regression(k=−1.073C+7.315N+0.223C/N−0.004L+33.900)including the variables of the carbon content(C),nitrogen content(N),the ratio of carbon to nitrogen(C/N)and lignin content(L)could be used to model the variations in the coefficients of decomposition rates of the straw of the six crops under the different treatments.The model simulated 92.1%(R^(2)=0.921,P<0.001)of the variation in the decomposition rates of the straw.The slope for the linear regression function fitting the relationship between the modelled and the observed decomposition rates of the straw was very close the 1:1 line.The validation analysis based on the residual straw mass after the different embedding days and the modelled decomposition coefficients of straw showed that the modelled and observed values of residual straw mass of different crops fitted well(R^(2)=0.922,P<0.001),indicating that this model effectively simulated the straw decomposition dynamics.【Conclusions】Compared with control,warming significantly increased the decomposition rates of the straw of maize,sweet potato and winter wheat during the initial decomposition period and the decomposition rates of rape straw during the whole growing season,but warming did not impact the decomposition rates of the straw of soybean,garlic.The coefficients of decomposition rates of crop straws could be modelled by the C,N,lignin content and C/N of crop straws.This model could also well estimate the remained straw mass of different crops after different embedding days.
作者
丁司丞
陈书涛
王瑾
张苗苗
胡正华
DING Si-cheng;CHEN Shu-tao;WANG Jin;ZHANG Miao-miao;HU Zheng-hua(Nanjing University of Information Science and Technology/Jiangsu Key Laboratory of Agricultural Meteorology,Nanjing,Jiangsu 210044,China;School of Applied Meteorology,Nanjing University of Information Science and Technology,Nanjing,Jiangsu 210044,China)
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2021年第11期2054-2062,共9页
Journal of Plant Nutrition and Fertilizers
基金
国家自然科学基金项目(41775151,41775152)。
关键词
增温
秸秆
分解率
碳含量
氮含量
木质素含量
warming
straw
decomposition rate
carbon content
nitrogen content
lignin content