不同品质凋落物分解对黄土高原草地土壤有机碳及其稳定性的影响  

Effects of litter decomposition with different qualities on soil organic carbon content and its stability in grassland on the Loess Plateau

作　　者：郭鑫 罗欢 许雪梅 马爱霞 尚振艳[1] 韩天虎 牛得草[1] 文海燕[1] 李旭东[1] GUO Xin;LUO Huan;XU Xue-mei;MA Ai-xia;SHANG Zhen-yan;HAN Tian-hu;NIU De-cao;WEN Hai-yan;LI Xu-dong(State Key Laboratory of Grassland Agro-ecosystems,College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou 730020,China;Gansu Vocational College of Agriculture,Lanzhou 730030,China;Gansu Grassland Technology Promotion Station,Lanzhou 730010,China)

机构地区：[1]兰州大学草地农业生态系统国家重点实验室,兰州大学草地农业科技学院,甘肃兰州730020 [2]甘肃农业职业技术学院,甘肃兰州730030 [3]甘肃省草原技术推广总站,甘肃兰州730010

出　　处：《草业学报》2023年第5期83-93,共11页Acta Prataculturae Sinica

基　　金：甘肃省科技计划(甘肃省自然科学基金重点项目,22JR5RA400);甘肃省科技计划(甘肃省自然科学基金项目,22JR5RA464);国家自然科学基金项目(31572458);甘肃省级林业和草原科技项目(2021kj071)资助。

摘　　要：植物凋落物是土壤有机碳(SOC)最重要的来源,凋落物的品质决定新碳(C)进入到土壤中形成SOC的数量和稳定性。本研究选取陇中黄土高原典型草原不同品质的凋落物(AS:铁杆蒿茎秆、SR:长芒草根、SL:长芒草叶片和SAL:苦豆子叶片),将凋落物与土壤共同培养,研究不同品质凋落物分解过程及其对SOC含量和稳定性的影响。结果表明:与低品质凋落物(AS和SR)相比,高品质凋落物(SL和SAL)因其较高的易分解可溶物含量和较低的碳氮比而具有相对较高的分解速率。分解2年后,各处理SOC含量均显著增加,高品质凋落物处理下SOC的增幅和新C形成效率均显著高于低品质凋落物,说明高品质凋落物分解后对SOC固存有较高的贡献。各处理对不同粒径土壤团聚体质量无显著影响。分解2年后,<0.053 mm土壤团聚体SOC含量在各处理下均显著升高,高品质凋落物处理较低品质凋落物处理下<0.053 mm土壤团聚体具有更高的SOC含量和新C形成效率;说明与低品质凋落物相比,高品质凋落物分解后更容易形成稳定的矿质结合态SOC。Plant litter is the most important source of soil organic carbon(SOC),and the quality of litter may affect the amount and stability of newly formed SOC.In this study,we evaluated the effects of decomposition of litters of different quality(AS:Artemisia sacrorum stem,SR:Stipa bungeana root,SL:S.bungeana leaf,SAL:Sophora alopecuroides leaf),which were selected from the typical grassland of the Loess Plateau in the middle of Gansu Province,on SOC and its stability.According to their chemical composition,litters were divided into high-quality litters(higher soluble components content and lower lignin content)and low-quality litters(lower soluble components content and higher lignin content).The litters were co-incubated with soil to study the decomposition process and determine how it affected SOC content and stability.Compared with low-quality litters(AS and SR),high-quality litters(SAL and SL)had a relatively higher decomposition rate due to their higher content of labile components and lower carbon/nitrogen(C/N).After decomposition for 2 years,the SOC content had increased in each treatment.The increases in SOC and the formation efficiency of new carbon(C)were significantly higher in the high-quality litter treatments than in the low-quality litter treatments.These results indicated that,compared with low-quality litters,high-quality litters made a greater contribution to SOC sequestration after decomposition.The amounts of all soil aggregate components did not vary significantly among treatments.After decomposition for 2 years,the SOC content in<0.053 mm soil aggregates was significantly increased in all the treatments.The SOC content and efficiency of new C formation in<0.053 mm soil aggregates were significantly higher in the high-quality litter treatments than in the low-quality litter treatments.Overall,these results show that,compared with low-quality litter,high-quality litter more readily forms stable mineral-associated organic matter after decomposition.

关 键 词：凋落物 化学组成 土壤团聚体 土壤有机碳 土壤有机碳稳定性 

分 类 号：S812.2[农业科学—草业科学]