Impact of grassland soil carbon saturation on litter decomposition and soil carbon sequestration

doi:10.11686/cyxb2025177

Abstract

Abstract:

Plant litter is an important source of soil organic carbon （SOC）. The formation and stability of SOC are not only directly related to plant carbon input but also affected by soil carbon saturation. In this study， leaves and roots of Stipa bungeana， a dominant species in the temperate grassland of the Loess Plateau， were selected as litter materials. They were co-cultured in the laboratory for 3 years with soils of different carbon saturation levels （with SOC contents of 9.02， 5.28， and 2.64 g·kg^-1， respectively）. The aim was to clarify the impact of soil carbon saturation on litter decomposition and SOC sequestration by analyzing the decomposition rate of litter and the changes in SOC in bulk soil and soil aggregates of various particle sizes under different carbon saturation conditions. The results showed that with decrease in soil carbon saturation， soil microbial biomass carbon gradually increased， while the litter decomposition rate significantly increased， the new carbon formation efficiency （NCE） in the bulk soil and the proportions of aggregates of all particle sizes also gradually increased， and the SOC content significantly increased. This indicates that soils with lower carbon saturation have a higher sequestration efficiency for exogenous organic carbon. Among the three soil aggregate fractions of decreasing size， 0.25-2.00 mm， 0.053-0.25 mm， and <0.053 mm， as soil carbon saturation decreased， more decomposed litter carbon was allocated to the <0.053 mm aggregates， which is conducive to the formation of mineral-associated organic carbon with high stability.

Key words: litter, soil carbon saturation, soil aggregates, soil carbon stability

Yu-qi JIANG, Xin GUO, Jia-chang JIANG, Xing-ming LIU, Chun-yan LIANG, Hai-yan WEN, De-cao NIU, Xu-dong LI. Impact of grassland soil carbon saturation on litter decomposition and soil carbon sequestration[J]. Acta Prataculturae Sinica, 2026, 35(3): 43-51.

Figures/Tables 7

References 32

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分解时间 Decomposition time （d）	凋落物 Litter	土壤碳饱和度 Soil carbon saturation	Olson 拟合方程 Olson fitting equation	分解系数 Decomposition coefficient （k）	P值 P value
1095	SL	C₁	y=4.5816e^-0.0201^t	0.0201±0.004c	<0.05
		C₂	y=4.5816e^-0.0287^t	0.0287±0.008b	<0.05
		C₃	y=4.5816e^-0.0319^t	0.0319±0.002a	<0.05
	SR	C₁	y=4.0804e^-0.0191^t	0.0191±0.003c	<0.05
		C₂	y=4.0804e^-0.0222^t	0.0222±0.005b	<0.05
		C₃	y=4.0804e^-0.0270^t	0.0270±0.007a	<0.05

分解时间 Decomposition time （d）	凋落物 Litter	土壤碳饱和度 Soil carbon saturation	Olson 拟合方程 Olson fitting equation	分解系数 Decomposition coefficient （k）	P值 P value
1095	SL	C₁	y=4.5816e^-0.0201^t	0.0201±0.004c	<0.05
		C₂	y=4.5816e^-0.0287^t	0.0287±0.008b	<0.05
		C₃	y=4.5816e^-0.0319^t	0.0319±0.002a	<0.05
	SR	C₁	y=4.0804e^-0.0191^t	0.0191±0.003c	<0.05
		C₂	y=4.0804e^-0.0222^t	0.0222±0.005b	<0.05
		C₃	y=4.0804e^-0.0270^t	0.0270±0.007a	<0.05

土壤碳饱和度 Soil carbon saturation	凋落物 Litter	分解时间 Decomposition time （d）	0.25~2.00 mm		0.053~0.250 mm		<0.053 mm
土壤碳饱和度 Soil carbon saturation	凋落物 Litter	分解时间 Decomposition time （d）	团聚体质量 Mass of soil aggregates （g）	土壤有机碳含量Soil organic carbon （g·kg^-1）	团聚体质量 Mass of soil aggregates （g）	土壤有机碳含量 Soil organic carbon （g·kg^-1）	团聚体质量 Mass of soil aggregates （g）	土壤有机碳含量 Soil organic carbon （g·kg^-1）
C₁	BV	0	13.62±0.07a	9.06±0.10b	20.42±0.21b	9.03±0.03ab	14.84±0.11b	9.63±0.09a
	SL	1095	13.59±0.06a	9.61±0.07a	20.56±0.02b	9.22±0.07a	14.67±0.05b	9.71±0.09a
	SR	1095	13.40±0.08a	9.52±0.27a	20.33±0.15b	8.92±0.20b	15.98±0.47a	9.74±0.05a
	CK	1095	13.57±0.23a	9.01±0.16b	21.07±0.25a	9.04±0.28ab	15.33±0.24ab	9.54±0.02a
C₂	BV	0	13.47±0.11a	5.46±0.13d	21.36±0.09a	5.41±0.20c	15.16±0.27b	5.42±0.17d
	SL	1095	13.51±0.12a	6.61±0.13c	21.10±0.12a	5.27±0.30c	14.67±0.02b	7.43±0.19b
	SR	1095	12.85±0.22b	6.32±0.25c	21.24±0.02a	5.72±0.27c	15.77±0.10a	6.77±0.11c
	CK	1095	13.81±0.21a	5.30±0.12d	20.87±0.12b	5.22±0.21c	14.59±0.04b	5.13±0.21d
C₃	BV	0	11.27±0.09c	3.31±0.21f	20.90±0.14b	2.32±0.12f	16.88±0.09a	2.79±0.10e
	SL	1095	12.57±0.07a	5.01±0.10e	21.23±0.13ab	3.61±0.07d	15.22±0.09b	5.35±0.12d
	SR	1095	12.17±0.12b	4.87±0.12e	21.17±0.21ab	3.12±0.31e	15.92±0.15b	5.01±0.12d
	CK	1095	11.11±0.09c	3.22±0.14f	21.53±0.16a	2.27±0.23f	16.69±0.08a	2.65±0.09e

土壤碳饱和度 Soil carbon saturation	凋落物 Litter	分解时间 Decomposition time （d）	0.25~2.00 mm		0.053~0.250 mm		<0.053 mm
土壤碳饱和度 Soil carbon saturation	凋落物 Litter	分解时间 Decomposition time （d）	团聚体质量 Mass of soil aggregates （g）	土壤有机碳含量Soil organic carbon （g·kg^-1）	团聚体质量 Mass of soil aggregates （g）	土壤有机碳含量 Soil organic carbon （g·kg^-1）	团聚体质量 Mass of soil aggregates （g）	土壤有机碳含量 Soil organic carbon （g·kg^-1）
C₁	BV	0	13.62±0.07a	9.06±0.10b	20.42±0.21b	9.03±0.03ab	14.84±0.11b	9.63±0.09a
	SL	1095	13.59±0.06a	9.61±0.07a	20.56±0.02b	9.22±0.07a	14.67±0.05b	9.71±0.09a
	SR	1095	13.40±0.08a	9.52±0.27a	20.33±0.15b	8.92±0.20b	15.98±0.47a	9.74±0.05a
	CK	1095	13.57±0.23a	9.01±0.16b	21.07±0.25a	9.04±0.28ab	15.33±0.24ab	9.54±0.02a
C₂	BV	0	13.47±0.11a	5.46±0.13d	21.36±0.09a	5.41±0.20c	15.16±0.27b	5.42±0.17d
	SL	1095	13.51±0.12a	6.61±0.13c	21.10±0.12a	5.27±0.30c	14.67±0.02b	7.43±0.19b
	SR	1095	12.85±0.22b	6.32±0.25c	21.24±0.02a	5.72±0.27c	15.77±0.10a	6.77±0.11c
	CK	1095	13.81±0.21a	5.30±0.12d	20.87±0.12b	5.22±0.21c	14.59±0.04b	5.13±0.21d
C₃	BV	0	11.27±0.09c	3.31±0.21f	20.90±0.14b	2.32±0.12f	16.88±0.09a	2.79±0.10e
	SL	1095	12.57±0.07a	5.01±0.10e	21.23±0.13ab	3.61±0.07d	15.22±0.09b	5.35±0.12d
	SR	1095	12.17±0.12b	4.87±0.12e	21.17±0.21ab	3.12±0.31e	15.92±0.15b	5.01±0.12d
	CK	1095	11.11±0.09c	3.22±0.14f	21.53±0.16a	2.27±0.23f	16.69±0.08a	2.65±0.09e