The impact of soil moisture on litter decomposition and soil organic carbon deposition in the temperate grasslands of the Loess Plateau

doi:10.11686/cyxb2025420

Abstract

Abstract:

Litter decomposition is a key process affecting the formation of soil organic carbon （SOC）， and soil moisture conditions exert a significant influence on this process. Investigating the effects of soil moisture changes on grassland litter decomposition and its role in soil organic carbon formation is conducive to clarifying the dynamic changes in soil carbon pools and their stabilization mechanisms in the context of climate change. In this study， Stipa bungeana， a dominant species in the temperate grasslands of the Loess Plateau-was selected for study. S. bungeana leaves （SL） and S. bungeana roots （SR） were co-cultured with soil for 3 years under different moisture conditions ［W₁： annual average soil moisture content （gravimetric water content of 7.16%）； W₂： 50% of soil field capacity （gravimetric water content of 23.55%）］. The decomposition characteristics of litter and the changes in soil organic carbon and organic carbon in soil aggregates under the different moisture conditions were analyzed. It was found that， compared with W₁， the soil microbial biomass carbon in the SL and SR treatments in the W₂ treatment increased （P<0.05） by 25.2% and 40.7%， respectively. The W₂ treatment not only significantly accelerated the litter decomposition rate but also significantly increased the SOC content （P<0.05）. In addition，adequate moisture conditions facilitate the formation of mineral-associated organic carbon in soils of semi-arid regions. Specifically， in the W₂ treatment， the new carbon formation efficiency of the SL and SR treatments increased significantly by 6.5% and 8.0% respectively compared with W₁ （P<0.05）. These findings indicate that in the temperate grasslands of semi-arid regions， an increase in soil moisture can not only promote litter decomposition， but also promote a greater allocation of litter carbon to soil aggregates <0.053 mm， thereby facilitating the formation of mineral-associated organic carbon.

Key words: soil moisture, litter, decomposition rate, soil aggregates, carbon stability

Huan LUO, Yu-qi JIANG, De-cao NIU, Ding GUO, Xu-dong LI. The impact of soil moisture on litter decomposition and soil organic carbon deposition in the temperate grasslands of the Loess Plateau[J]. Acta Prataculturae Sinica, 2026, 35(8): 14-21.

Figures/Tables 7

Table 1 Changes in the chemical composition of litter under different moisture treatments （g·kg-1）

凋落物 Litter	培养时间 Co-culture time （a）	处理 Treatment	可溶性成分 Soluble components	半纤维素 Hemicellulose	纤维素 Cellulose	木质素 Lignin
叶片Leave （SL）	0	W₀	0.135±0.001b	0.163±0.001a	0.147±0.000a	0.055±0.000b
	3	W₁	0.204±0.003a	0.114±0.010b	0.036±0.011b	0.090±0.010a
	3	W₂	0.210±0.006a	0.113±0.009b	0.026±0.007b	0.108±0.017a
根Root （SR）	0	W₀	0.101±0.000b	0.126±0.001a	0.165±0.001a	0.061±0.000b
	3	W₁	0.148±0.025ab	0.117±0.016a	0.069±0.010b	0.144±0.007a
	3	W₂	0.195±0.042a	0.109±0.006a	0.050±0.009b	0.166±0.020a

Fig.1 Dry matter residue rates of litters under different moisture treatments

Fig.2 Changes in the litter carbon contents under different moisture treatments

Fig.3 Changes in the soil organic carbon content under different moisture treatments

Fig.4 Net changes in the organic carbon content of soil aggregates with different particle sizes under different moisture treatments

Fig.5 New carbon formation efficiency in soil aggregates of various particle sizes under different moisture treatments

Fig.6 Soil microbial biomass carbon content under different moisture treatments

References 33

[1]	Bontti E E， Decant J P， Munson S M， et al. Litter decomposition in grasslands of central North America （US Great Plains）. Global Change Biology， 2009， 15（5）： 1356-1363.
[2]	Chen Y C， Ma S Q， Lu X Y. Litter decomposition and nutrient dynamics of typical plant species in an alpine steppe ecosystem in northern Tibet. Pratacultural Science， 2019， 36（4）： 1066-1073.
	陈有超，马书琴，鲁旭阳. 藏北高寒草原典型物种凋落物分解与养分动态. 草业科学， 2019， 36（4）： 1066-1073.
[3]	Zhang G S， Huang G B. Soil organic carbon sequestration potential in cropland. Acta Ecologica Sinica， 2005， 25（2）： 351-357.
	张国盛，黄高宝. 农田土壤有机碳固定潜力研究进展. 生态学报， 2005， 25（2）： 351-357.
[4]	Jin X X， Wang J K， Sun L J， et al. Progress of carbon cycle in farmland and sequestration in soil aggregates revealed by stable ¹³C isotope. Soils， 2017， 49（2）： 217-224.
	金鑫鑫，汪景宽，孙良杰，等. 稳定¹³C同位素示踪技术在农田土壤碳循环和团聚体固碳研究中的应用进展. 土壤， 2017， 49（2）： 217-224.
[5]	Epstein H E， Burke I C， Lauenroth W K. Regional patterns of decomposition and primary production rates in the US Great Plains. Ecology， 2002， 83（2）： 320-327.
[6]	Wang M M， Hou F J. Influence of main factors on grass litter decomposition. Pratacultural Science， 2012， 29（10）： 1631-1637.
	王苗苗，侯扶江. 草地凋落物分解的主要影响因素. 草业科学， 2012， 29（10）： 1631-1637.
[7]	Thakur M P， Milcu A， Manning P， et al. Plant diversity drives soil microbial biomass carbon in grasslands irrespective of global environmental change factors. Global Change Biology， 2015， 21（11）： 4076-4085.
[8]	Gao C B， Chang Z Q. Effects of water input on litter decomposition and nitrogen dynamics of desert vegetation in the Liangucheng National Nature Reserve， Gansu， China. Journal of Desert Research， 2021， 41（2）： 145-152.
	高承兵，常宗强. 降水量对连古城自然保护区荒漠植被凋落物分解和氮状态的影响. 中国沙漠， 2021， 41（2）： 145-152.
[9]	Chen Q， Li G， Li H D， et al. Soil moisture determines the consistency of organic matter decomposition in field and lab test patterns. Catena， 2024， 246： 108485.
[10]	Wen H Y， Fu H， Guo D. Influence of nitrogen addition on Stipa bungeana and Heteropappus altaicus litter decomposition and nutrient release in a steppe located on the Loess Plateau. Acta Ecologica Sinica， 2017， 37（6）： 2014-2022.
	文海燕，傅华，郭丁. 黄土高原典型草原优势植物凋落物分解及养分释放对氮添加的响应. 生态学报， 2017， 37（6）： 2014-2022.
[11]	Lu W J， Qi J Y， Wu C， et al. Effects of mixed litter with different degrees of decomposition on the decomposition characteristics of semi-arid grassland in northern Shanxi. Acta Prataculturae Sinica， 2023， 32（12）： 47-57.
	路文杰，齐晋云，吴聪，等. 晋北半干旱草地不同分解程度凋落物混合对分解特征的影响. 草业学报， 2023， 32（12）： 47-57.
[12]	Wang Q W， Yu D P， Dai L M， et al. Research progress in water use efficiency of plants under global climate change. Chinese Journal of Applied Ecology， 2010， 21（12）： 3255-3265.
	王庆伟，于大炮，代力民，等. 全球气候变化下植物水分利用效率研究进展. 应用生态学报， 2010， 21（12）： 3255-3265.
[13]	Soong J L， Parton W J， Calderon F， et al. A new conceptual model on the fate and controls of fresh and pyrolized plant litter decomposition. Biogeochemistry， 2015， 124： 27-44.
[14]	Haddix M L， Paul E A， Cotrufo M F. Dual， differential isotope labeling shows the preferential movement of labile plant constituents into mineral-bonded soil organic matter. Global Change Biology， 2016， 22（6）： 2301-2312.
[15]	Chung H， Grove J H， Six J. Indications for soil carbon saturation in a temperate agroecosystem. Soil Science Society of America Journal， 2008， 72（4）： 1132-1139.
[16]	Guo X， Luo H， Xu X M， et al. Effects of litter decomposition with different qualities on soil organic carbon content and its stability in grassland on the Loess Plateau. Acta Prataculturae Sinica， 2023， 32（5）： 83-93.
	郭鑫，罗欢，许雪梅，等.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. 草业学报， 2023， 32（5）： 83-93.
[17]	Lavallee J M， Conant R T， Paul E A， et al. Incorporation of shoot versus root-derived ¹³C and ¹⁵N into mineral-associated organic matter fractions： Results of a soil slurry incubation with dual-labelled plant material. Biogeochemistry， 2018， 137（3）： 379-393.
[18]	Swift M J， Heal O W， Anderson J M. Decomposition in terrestrial ecosystems. Berkeley： University of California Press， 1979.
[19]	Yang L L， Gong J R， Liu M， et al. Advances in the effect of nitrogen deposition on grassland litter decomposition. Chinese Journal of Plant Ecology， 2017， 41（8）： 894-913.
	杨丽丽，龚吉蕊，刘敏，等. 氮沉降对草地凋落物分解的影响研究进展. 植物生态学报， 2017， 41（8）： 894-913.
[20]	Yan Z Q， Qi Y C， Peng Q， et al. Advances in the effects of simulated precipitation and nitrogen deposition on grassland biomass. Acta Agrestia Sinica， 2017， 25（6）： 1165-1170.
	闫钟清，齐玉春，彭琴，等. 模拟降水和氮沉降增加对草地生物量影响的研究进展. 草地学报， 2017， 25（6）： 1165-1170.
[21]	Dirks I， Navon Y， Kanas D. Atmospheric water vapor as driver of litter decomposition in Mediterranean shrubland and grassland during rainless seasons. Global Change Biology， 2010， 16（10）： 2799-2812.
[22]	Brandt L A， King J Y， Hobbie S E， et al. The role of photodegradation in surface litter decomposition across a grassland ecosystem precipitation gradient. Ecosystems， 2010， 13（5）： 765-781.
[23]	Brown M E， Chang M C. Exploring bacterial lignin degradation. Current Opinion in Chemical Biology， 2014， 19（1）： 1-7.
[24]	Abiven S， Menasseri S， Chenu C. The effects of organic inputs over time on soil aggregate stability-A literature analysis. Soil Biology and Biochemistry， 2009， 41（1）： 1-12.
[25]	Cotrufo M F， Wallenstein M D， Boot C M， et al. The microbial efficiency-matrix stabilization （MEMS） framework integrates plant litter decomposition with soil organic matter stabilization： Do labile plant inputs form stable soil organic matter. Global Change Biology， 2013， 19（4）： 988-995.
[26]	Castro H F， Classen A T， Austin E E， et al. Soil microbial community responses to multiple experimental climate change drivers. Applied & Environmental Microbiology， 2010， 76（4）： 999-1007.
[27]	Wang B R， An S S， Liang C， et al. Microbial necromass as the source of soil organic carbon in global ecosystems. Soil Biology and Biochemistry， 2021， 162： 108422.
[28]	Sokol N W， Bradford M A. Microbial formation of stable soil carbon is more efficient from belowground than aboveground input. Nature Geoscience， 2019， 12（1）： 46-53.
[29]	Georgiou K， Jackson R B， Vinduková O， et al. Global stocks and capacity of mineral-associated soil organic carbon. Nature Communications， 2022， 13： 3797.
[30]	Haddix M L， Gregorich E G， Helgason B L， et al. Climate， carbon content， and soil texture control the independent formation and persistence of particulate and mineral-associated organic matter in soil. Geoderma， 2020， 363： 114160.
[31]	Katherine S R， Michael B， John M B， et al. Thirty years of increased precipitation modifies soil organic matter fractions but not bulk soil carbon and nitrogen in a mesic grassland. Soil Biology and Biochemistry， 2023， 185： 109145.
[32]	Clarholm M， Skyllberg U， Rosling A. Organic acid induced release of nutrients from metal-stabilized soil organic matter-The unbutton model. Soil Biology and Biochemistry， 2015， 84： 168-176.
[33]	Laub M， Samuel S， Patma V， et al. Litter quality and microbes explain aggregation differences in a tropical sandy soil. Journal of Soil Science and Plant Nutrition， 2022， 22（1）： 848-860.