轻度火烧对滨海沙地人工林土壤呼吸速率和非生物因子的影响

doi:10.17521/cjpe.2022.0130

摘要/Abstract

摘要：

探究轻度火烧后土壤呼吸及其组分变化规律以及对林地环境因子的影响, 可为林火干扰条件下滨海沙地人工林土壤碳排放估算提供科学依据。该研究以闽南沿海地区木麻黄(Casuarina equisetifolia)人工林火烧迹地和对照样地为研究对象, 于2019年9月至2020年8月采用LI-8100土壤碳通量自动测量系统测定土壤总呼吸速率(R_S)和异养呼吸速率(R_H), 同时测定10 cm深处的土壤温度(T₁₀)、湿度(W₁₀)和0-10 cm土壤的物理化学性质, 探讨轻度火烧对林地土壤R_S和R_H以及非生物因子的影响。结果表明: 火烧迹地土壤全年平均R_S和R_H分别为(2.37 ± 0.65)和(2.05 ± 0.63) μmol·m^-2·s^-1, 对照样地土壤全年平均R_S和R_H分别为(2.86 ± 1.08)和(2.51 ± 1.08) μmol·m^-2·s^-1, 火烧迹地与对照样地土壤呼吸速率及其组分存在显著差异。除对照样地土壤R_H外, 两块样地土壤呼吸速率及其组分与土壤温度呈极显著指数相关关系, 与土壤水分的相关关系均未达到显著水平。土壤呼吸速率与土壤可溶性有机碳、土壤微生物生物量氮含量呈极显著正相关关系, 与土壤可溶性有机氮含量呈显著正相关关系, 与土壤微生物生物量碳含量呈显著负相关关系。轻度火烧对木麻黄人工林土壤呼吸及其组分均有抑制作用, 说明林火干扰对森林生态系统土壤呼吸和碳循环具有重要影响。

关键词: 林火干扰, 土壤呼吸速率, 异养呼吸, 土壤温度, 土壤含水量

Abstract:

Aims This study aimed to explore change in soil respiration and its components after mild fire, as well as its influence on forest environmental factors, which could provide a scientific basis for the estimation of the soil carbon emission of coastal sandy plantation under the condition of forest fire disturbance.

Methods We conducted an experiment in the Casuarina equisetifolia plantation burnt area and the control plot to measure the total soil respiration rate (R_S) and heterotrophic respiration rate (R_H) in the coastal areas of southern Fujian from September 2019 to August 2020, using the LI-8100 soil carbon flux automatic measurement system. Meanwhile, the soil temperature at the depth of 10 cm (T₁₀), soil volumetric water content at the depth of 10 cm (W₁₀), and soil physical and chemical properties at the depth of 0-10 cm were measured, in order to explore the effects of mild fire on soil R_S, R_H and abiotic factors.

Important findings There were significant differences in soil respiration rate and its components between the burned area and the control area. Our results showed that the annual average soil R_S and R_H in the burned area were (2.37 ± 0.65) and (2.05 ± 0.63) μmol·m^-2·s^-1, respectively. In contrast, the annual average soil R_S and R_H in the control plot were (2.86 ± 1.08) and (2.51 ± 1.08) μmol·m^-2·s^-1, respectively. Soil respiration rate and its components were significantly correlated with soil temperatures in the two plots, except soil R_H in the control plot, but their relationships with soil moisture did not reach a significant level. There was significant positive correlation of soil respiration rate with dissolved organic carbon content, microbial biomass nitrogen content and dissolved organic nitrogen content, but significant negative correlation with microbial biomass carbon content. Overall, we found that mild burning inhibited soil respiration and its components in C. equisetifolia plantation, indicating that fire disturbance had an important impact on soil respiration and carbon cycle in forest ecosystems.

Key words: forest fire disturbance, soil respiration, heterotrophic respiration, soil temperature, soil water content

沈健, 何宗明, 董强, 郜士垒, 林宇. 轻度火烧对滨海沙地人工林土壤呼吸速率和非生物因子的影响. 植物生态学报, 2023, 47(7): 1032-1042. DOI: 10.17521/cjpe.2022.0130

SHEN Jian, HE Zong-Ming, DONG Qiang, GAO Shi-Lei, LIN Yu. Effects of mild fire on soil respiration rate and abiotic factors in coastal sandy plantation. Chinese Journal of Plant Ecology, 2023, 47(7): 1032-1042. DOI: 10.17521/cjpe.2022.0130

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https://www.plant-ecology.com/CN/Y2023/V47/I7/1032

图/表 10

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样点 Site	平均树高 Mean tree height (m)	平均胸径 Mean DBH (cm)	土壤pH Soil pH	土壤密度 Soil density (g·cm^-3)	郁闭度 Canopy density	存活率 Survival rate (%)
火烧迹地 Burned plot	9.77 ± 0.40	11.13 ± 0.44	5.22 ± 0.14	1.29 ± 0.02	0.85	78.44
对照样地 Control plot	10.40 ± 0.42	12.87 ± 0.53	5.06 ± 0.04	1.24 ± 0.08	0.91	82.45

样点 Site	平均树高 Mean tree height (m)	平均胸径 Mean DBH (cm)	土壤pH Soil pH	土壤密度 Soil density (g·cm^-3)	郁闭度 Canopy density	存活率 Survival rate (%)
火烧迹地 Burned plot	9.77 ± 0.40	11.13 ± 0.44	5.22 ± 0.14	1.29 ± 0.02	0.85	78.44
对照样地 Control plot	10.40 ± 0.42	12.87 ± 0.53	5.06 ± 0.04	1.24 ± 0.08	0.91	82.45

样点 Site	休眠季 Dormant season		生长季 Growing season		全年 Whole year
样点 Site	R_S	R_H	R_S	R_H	R_S	R_H
火烧迹地 Burned polt	1.91 ± 0.37^Ab	1.55 ± 0.28^Ab	2.69 ± 0.61^Ba	2.41 ± 0.56^Ba	2.37 ± 0.65^Ba	2.05 ± 0.63^Ba
对照样地 Control plot	1.88 ± 0.32^Ac	1.53 ± 0.36^Ac	3.56 ± 0.87^Aa	3.22 ± 0.84^Aa	2.86 ± 1.08^Ab	2.51 ± 1.08^Ab

样点 Site	休眠季 Dormant season		生长季 Growing season		全年 Whole year
样点 Site	R_S	R_H	R_S	R_H	R_S	R_H
火烧迹地 Burned polt	1.91 ± 0.37^Ab	1.55 ± 0.28^Ab	2.69 ± 0.61^Ba	2.41 ± 0.56^Ba	2.37 ± 0.65^Ba	2.05 ± 0.63^Ba
对照样地 Control plot	1.88 ± 0.32^Ac	1.53 ± 0.36^Ac	3.56 ± 0.87^Aa	3.22 ± 0.84^Aa	2.86 ± 1.08^Ab	2.51 ± 1.08^Ab

项目 Item	是否断根 Trenched or not	样点 Site	休眠季 Dormant season	生长季 Growing season	全年 Whole year
土壤温度 Soil temperature (℃)	未断根 Untrenched	火烧迹地 Burned plot	15.84 ± 3.74^Ac	23.77 ± 3.08^Aa	20.47 ± 5.17^Ab
	未断根 Untrenched	对照样地 Control plot	15.13 ± 3.40^Ac	23.64 ±3.12^Aa	20.10 ± 5.30^Ab
	断根 Trenched	火烧迹地 Burned plot	16.05 ± 3.73^Ac	24.01 ± 3.16^Aa	20.63 ± 5.20^Ab
	断根 Trenched	对照样地 Control plot	15.35 ± 3.48^Ac	23.70 ± 3.15^Aa	20.22 ± 5.27^Ab
土壤含水量 Soil water content (%)	未断根 Untrenched	火烧迹地 Burned plot	4.58 ± 1.34^Aa	4.00 ± 1.76^Aa	4.25 ± 1.63^Aa
	未断根 Untrenched	对照样地 Control plot	3.45 ± 1.23^Ba	3.82 ± 1.75^Ba	3.67 ± 1.56^Ba
	断根 Trenched	火烧迹地 Burned plot	5.11 ± 1.47^Aa	4.47 ± 1.77^Aa	4.57 ± 1.76^Aa
	断根 Trenched	对照样地 Control plot	4.42 ± 1.64^Aa	5.34 ± 2.68^Aa	4.96 ± 2.35^Aa