基于DNDC模型分析氮添加对内蒙古草甸和荒漠草地碳动态的影响  

Analysis on the Impact of Nitrogen Addition on Carbon Dynamics in Inner Mongolia Meadows and Desert Grasslands Based on the DNDC Model

作　　者：张新宇 方昭 焦峰[1] Zhang Xinyu;Fang Zhao;Jiao Feng(Institute of Soil and Water Conservation,Northwest A&F University,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学水土保持研究所,陕西杨凌712100

出　　处：《水土保持研究》2024年第5期84-92,101,共10页Research of Soil and Water Conservation

基　　金：国家自然科学基金项目“黄土丘陵区土壤斥水性及其对降水入渗机制的影响研究”(41977426)。

摘　　要：[目的]确定内蒙古不同草地类型在氮沉降背景下植物生物量碳和土壤有机碳的变化,探究DNDC模型对该区域草地碳动态模拟的适用度,对减缓气候变化和实现“双碳”目标具有重要意义。[方法]通过调查内蒙古草甸和荒漠草地对氮沉降的响应,并利用DNDC模型进行模拟验证。设置不同氮添加梯度[0,5,10,15,20,25,30 gN/(m^(2)·a)],分析了氮添加对不同草地碳库的影响,评估了DNDC模型对其模拟的差异。[结果](1)与空白对照相比,氮添加对草甸草地和荒漠草地地上生物量碳具有促进作用,平均分别增加了72.68%和66.52%,草甸草地在N_(5)处理下地下生物量碳达到最大值(240.93 gC/kg),荒漠草地则在N_(4)处理下增幅最大(129.67 gC/kg);(2)相对于对照组,氮添加对两种草地地下生物量碳没有显著影响,与地上生物量碳的响应不同,但整体而言,地下碳量表现为草甸草原>荒漠草原;(3)氮添加对两种草地土壤有机碳含量的影响均不显著,且不同氮添加处理间也没有显著性差异,总体而言,草甸草地土壤有机碳含量高于荒漠草地;(4) DNDC模型能够较好地模拟研究区草甸草地和荒漠草地的地上、地下生物量碳和土壤有机碳,模型的模拟值与实测值基本一致,决定系数R^(2)分别为0.9426,0.756 8,0.825 7,0.523 8,0.909 9,0.955 2,0.861 0,0.732 4,模型效率系数E分别为0.834 5,0.674 8,0.799 4,0.428 8,0.873 1,0.926 5,0.716 8,0.538 1,点位模拟效果整体良好,但对于生物量碳的模拟吻合程度更好,且对荒漠草原的模拟优于草甸草地。[结论]氮添加促进了不同干旱类型草地的固碳能力,DNDC模型能较好反映氮沉降对内蒙古两种类型草地的影响,因此模型可用于模拟内蒙古草地生态系统的生物量碳和土壤有机碳。[Objective] The aims of this study are to determine the changes of plant biomass carbon and soil organic carbon in different grassland types in Inner Mongolia under the background of nitrogen deposition,and to investigate the applicability of the DNDC model to simulate the carbon dynamics of grasslands in this region,which is of great significance for mitigating climate change and achieving the goal of the ‘dual-carbon strategy'.[Methods] The response of Inner Mongolian meadows and desert grasslands to nitrogen deposition was investigated and verified by simulation using the DNDC model.The effects of nitrogen addition on carbon pools in different grasslands were analyzed by setting different gradients of nitrogen addition [0,5,10,15,20,25,30 gN/(m^(2)·a)],and the differences in their simulations by the DNDC model were evaluated.[Results](1) Compared with the control,nitrogen addition promoted aboveground biomass carbon in meadow grassland and desert grassland,with an average increase of 72.68% and 66.52%,respectively,and the belowground biomass C of meadow grassland reached the maximum under N_(5) treatment(240.93 gC/kg),while the increase of the desert grassland was the largest under the N_(4) treatment(129.67 gC/kg).(2) Compared with the control,nitrogen addition did not significantly affect belowground biomass carbon of the two grasslands,with a different response from that of above-ground biomass carbon.Nitrogen addition had no significant effect on the below-ground biomass carbon of the two types of grassland relative to the control group,and the response was different from that of the aboveground biomass carbon,but on the whole,the below-ground carbon showed the order:meadow grassland>desert grassland.(3) The effect of nitrogen addition on the soil organic carbon content of the two types of grassland was not significant,and there was no significant difference between the different treatments of nitrogen addition,and on the whole,soil organic carbon content of meadow grassland was higher than that of dese

关 键 词：内蒙古草地 碳动态 DNDC模型 氮添加 

分 类 号：S812[农业科学—草业科学]