Effects of stand density on soil respiration and labile organic carbon in different aged Larix principis-rupprechtii plantations

Abstract Background The carbon pools of forest soils play a vital role in global carbon sequestration and emissions. Forest management can regulate the sequestration and output of forest soil carbon pools to a certain extent; however, the kinetics of the effects of forest density on soil carbon pools require further investigation. Methods We established sample plots with stand density gradients in three different aged Larix principis-rupprechtii plantations and quantified the soil respiration, soil organic carbon (SOC), soil dissolved organic carbon (DOC), microbial biomass carbon (MBC), light fraction organic carbon (LFOC), and readily oxidized carbon (ROC). Results and conclusions During the growth and development of plantations, stand density is an essential factor that impacts soil respiration and its associated elements. Moderate density was observed to promote both the soil and heterotrophic respiration rates and the sequestration of MBC and LFOC, whereas it inhibited the sequestration of ROC. The soil, heterotrophic, and autotrophic respiration rates of older forest stands were relatively rapid, whereas the contents of SOC, MBC, LFOC, DOC, and ROC were higher and more sensitive to changes in stand density. The MBC, LFOC, and ROC in soil labile organic carbon were closely related to both the soil and heterotrophic respiration, but not the SOC. Among them, the LFOC and MBC played the roles of “warehouse” and “tool” and were significantly correlated with soil and heterotrophic respiration. The ROC, as a “raw material”, exhibited a significantly negative correlation with the soil and heterotrophic respiration. When the soil and heterotrophic respiration rates were rapid, the ROC content in the soil maintained the low level of a “dynamically stabilized” state. The stand density regulated heterotrophic respiration by affecting the soil labile organic carbon, which provided an essential path for the stand density to regulate soil respiration.

Download Full-text

Effects of Stand Density on Soil Respiration and Soil Labile Organic Carbon and Their Influence Mechanism in Larix Principis-Rupprechtii Plantations

10.21203/rs.3.rs-143559/v1 ◽

2021 ◽

Author(s):

TaiRui Liu ◽

Daoli Peng ◽

Zhijie Tan ◽

Jinping Guo ◽

Yunxiang Zhang

Keyword(s):

Forest Management ◽

Organic Carbon ◽

Soil Respiration ◽

Soil Carbon ◽

Forest Soil ◽

Stand Density ◽

Carbon Pool ◽

Labile Organic Carbon ◽

Soil Carbon Pool ◽

Soil Labile Organic Carbon

Abstract BackgroundForest soil carbon pool plays a vital role in the global carbon sequestration and carbon emission. Forest management can regulate the sequestration and output of forest soil carbon pool to a certain extent, but mechanism of forest density effects on soil carbon pool still needs to be further researched. MethodsWe established sample plots with density gradients in three-age stands of Larix principis-rupprechtii plantation and measured soil respiration (RS), soil organic carbon (SOC), soil dissolved organic carbon (DOC), and microbial biomass carbon (MBC), light fraction organic carbon (LFOC), and easily oxidizeable organic carbon (ROC). Results and ConclusionsThe results showed that, among the forest stands of three ages, RS, heterotrophic respiration (RH), MBC, LFOC, ROC of different stand density levels were significantly different. Moderate density promotes RS rate and RH rate and the sequestration of MBC and LFOC and inhibits ROC sequestration. With the increase of forest stand density, RS, RH, LFOC, and MBC first increased and then decreased, and ROC first decreased and then increased, the quadratic function could fit these changing trends. The RS, RH, and autotrophic respiration (RA) rates of older forest stands were relatively fast, and contents of SOC, MBC, LFOC, DOC, and ROC were higher, and they were more sensitive to changes in stand density. SOC, LFOC, MBC, DOC, and ROC explained 56.05% variations of RS, Rh, and RA. MBC, LFOC, and ROC in soil labile organic carbon were closely related to RS and Rh, but not SOC. Among them, LFOC and MBC played the role of "warehouse" and "tool" and significantly correlated with RS and Rh. ROC, as "raw material," had a significant negative correlation with RS and RH. When the RS and RH rate were fast, ROC maintained a dynamic and stable state of low soil content. Stand density could regulate RH by affecting soil labile organic carbon, an essential path for stand density to regulate soil respiration. Given soil carbon pool significance in forest ecosystems, Continuous research on soil respiration and stand density is suggested to bridge the gaps in our comprehension of the Regulation of Forest Management on forest soil carbon pool.

Download Full-text

Studying the relationship between total organic carbon and soil carbon pools under different land management systems of Garo hills, Meghalaya

Journal of Environmental Management ◽

10.1016/j.jenvman.2019.110002 ◽

2020 ◽

Vol 257 ◽

pp. 110002 ◽

Cited By ~ 1

Author(s):

Gaurav Mishra ◽

Avishek Sarkar

Keyword(s):

Organic Carbon ◽

Total Organic Carbon ◽

Soil Carbon ◽

Land Management ◽

Management Systems ◽

Carbon Pools ◽

Soil Carbon Pools ◽

Garo Hills ◽

The Relationship

Download Full-text

Seasonal changes in soil labile organic carbon pools within a Phyllostachys praecox stand under high rate fertilization and winter mulch in subtropical China

Forest Ecology and Management ◽

10.1016/j.foreco.2006.06.010 ◽

2006 ◽

Vol 236 (1) ◽

pp. 30-36 ◽

Cited By ~ 80

Author(s):

P.K. Jiang ◽

Q.F. Xu ◽

Z.H. Xu ◽

Z.H. Cao

Keyword(s):

Organic Carbon ◽

Seasonal Changes ◽

High Rate ◽

Carbon Pools ◽

Subtropical China ◽

Labile Organic Carbon ◽

Soil Labile Organic Carbon ◽

Winter Mulch ◽

Phyllostachys Praecox

Download Full-text

How does agroecology practices impact soil carbon stock and fluxes in a maize field?

10.5194/egusphere-egu21-14949 ◽

2021 ◽

Author(s):

Nicolas L. Breil ◽

Thierry Lamaze ◽

Vincent Bustillo ◽

Benoit Coudert ◽

Solen Queguiner ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Respiration ◽

Carbon Cycle ◽

Soil Temperature ◽

Soil Carbon ◽

Carbon Stock ◽

Management Practices ◽

Crop Management ◽

Respiration Rates

Soil plays a major role on carbon cycle, through both carbon stock which is one of the most important carbon terrestrial pool and soil CO2 efflux which represents one of the largest amounts of natural carbon emissions. It is known that soil respiration, through roots respiration and carbon mineralisation by microorganisms, is mainly controlled by temperature and humidity but the impact of crop management practices still needs to be investigated. Previous studies have demonstrated that crop management and more particularly reduced or no-tillage (NT) as well as cover-crops (CC) play a key role to mitigate soil respiration and increase soil organic carbon (SOC) content, but the impacts of the synergy of these practices are still unclear. Our study aims at better understanding the effect of sustainable agriculture through agroecological crop management practices on soil carbon dynamics.Soil respiration was measured in south-west of France on two distinct sites, CAS in 2018 and ABA in 2019, characterized by different initial soil carbon content, 106.9 % higher in CAS than in ABA. Each site included two joint maize fields using agroecological (NT and CC, named Agroeco) and conventional (tillage and bare soil, named Conv) practises. Agroeco have been settled for 12 and 19 years at CAS and ABA, respectively, at the time of experiment. Soil respiration chamber as well as temperature and moisture sensors were used to collect data twice a month, while pedoclimatic variables were monitored continuously on each field. Soil samples were collected in the fields before the experiment to define SOC and nutrient content as well as physical properties, through the entire soil profile.Mean soil respiration rate was higher on ABA-Agroeco (0.86&#160;g CO2&#160;m-&#178;&#160;h-1) than on ABA-Conv (0.50&#160;g CO2&#160;m-&#178;&#160;h-1) and was significantly correlated with soil temperature and humidity at Conv and only with soil temperature at Agroeco. Similar relations were found at CAS but with lower soil respiration rates. SOC concentration for ABA in the top 0-15&#160;cm was higher at Agroeco (13.4&#160;g&#160;kg-1) than at Conv (8.0&#160;g&#160;kg-1) but little difference was found at CAS where SOC was high. These results suggest that soil respiration rates depend less on soil humidity on Agroeco than on Conv because agroecology management practices both keep more water at the surface and store additional soil organic carbon in soils, inducing more activity through the carbon cycle with higher soil respiration rate. For both sites, agroecological practices induced higher SOC content compared to conventional ones, however, only for ABA site, soil respiration was higher for agroecological field while SOC content was higher. This study supports the idea that agroecological management practices can increase carbon cycle activity by increasing soil carbon stocks thus allowing the mitigation of greenhouse gases emissions and climate change, even by increasing soil CO2 efflux.

Download Full-text