长期氮添加对苏北杨树人工林碳储量的影响

Effects of Long-Term Nitrogen Addition on Carbon Storage of Poplar Plantation in North of Jiangsu

[目的]量化分析氮添加对南方杨树人工林碳储量分配格局的影响,为进一步提升我国杨树人工林在实现“双碳”战略目标中的作用,进而为我国“双碳”战略新时代背景下杨树人工林生产经营模式优化及技术集成提供理论支撑。[方法]基于东台林场杨树人工林长期氮添加样地,采用随机区组设置5个不同浓度氮处理:N_(0)〔0 g/(m^(2)·a)〕、N_(1)〔5 g/(m^(2)·a)〕、N_(2)〔10 g/(m^(2)·a)〕、N_(3)〔15 g/(m^(2)·a)〕、N_(4)〔30 g/(m^(2)·a)〕,研究长期氮添加对杨树人工林乔木层、土壤层、凋落物层、林下植被层碳储量的影响。[结果](1)与对照相比,杨树人工林乔木层碳储量在N_(3),N_(4)处理下显著增加,在N_(3)处理下最为显著,提高了21.6%;(2)各处理均显著提高了0—15 cm土层的土壤碳储量,但对30—45 cm土层的土壤碳储量没有显著影响;(3)N_(2),N_(3),N_(4)对凋落物层碳储量影响显著,N_(3)对其影响最强,提高了49.7%;各处理均降低了林下植被层碳储量,但差异不显著;(4)相关性分析结果表明:杨树人工林各层碳储量与土壤中TN,MBN,DON,DOC呈正相关,与pH,C/N呈负相关。[结论]在N_(3)处理下,即15 g/(m^(2)·a)对东台杨树人工林碳储量的影响最大,有利于其生态系统碳储量快速且稳定积累。

[Objective]In order to further enhance the role of China′s poplar plantation in achieving the China′s dual carbon goals,the impact of nitrogen addition on the carbon storage allocation pattern of southern poplar plantation was quantitatively analyzed,and theoretical support was provided for the optimization of production and management mode and technology integration of poplar plantation in the new era of China′s dual carbon goals.[Methods]Based on the long-term nitrogen addition plot of poplar plantation in Dongtai Forest Farm,five nitrogen treatments with different concentrations,N_(0)〔0 g/(m^(2)·a)〕,N_(1)〔5 g/(m^(2)·a)〕,N_(2)〔10 g/(m^(2)·a)〕,N_(3)〔15 g/(m^(2)·a)〕,N_(4)〔30 g/(m^(2)·a)〕,were set in random block groups.The effects of long-term nitrogen addition on carbon storage in tree layers,soil layer,litter layer and understory layer of poplar plantation were studied.[Results](1)Compared with the control,the carbon storage of poplar plantation significantly increased under the treatments of N_(3)and N_(4),and most significantly increased by 21.6%;under the treatment of N_(3).(2)All treatments significantly increased soil carbon storage in 0—15 cm soil layer,but had no significant effect on soil carbon storage in 30—45 cm soil layer.(3)N_(2),N_(3)and N_(4)had significant effects on litter carbon storage,and N_(3)had the strongest effect,increasing by 49.7%.All treatments reduced the carbon storage of understory vegetation layer,but the difference was not significant.(4)Correlation analysis showed that the carbon storage in each layer of poplar plantation was positively correlated with TN,MBN,DON and DOC in soil,and negatively correlated with pH and C/N.[Conclusion]Under N_(3)treatment,15 g/(m^(2)·a),had the greatest effect on carbon storage in Dongtai poplar plantation,which was conducive to the rapid and stable accumulation of carbon storage in the ecosystem.