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Changes in litter decomposition and soil organic carbon in a reforested tropical deciduous cover (India)

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  • Bhaskaracharya College of Applied Sciences University of Delhi

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Soil organic carbon (SOC) up to 1 m depth originates from contemporary vegetation cover dating from past millennia. Deforestation and reforestation with economically important species is influencing soil carbon sequestration. An attempt has been made in this study to evaluate the impact of vegetation cover change (due to replacement of natural heterogeneous cover by teak and bamboo) on SOC using carbon isotopes (δ13C, 14C) in a tropical system (India). A litter decomposition study was carried out to understand the impact of differences in vegetation characteristics (specifically of leaves) on decomposition. Both experiments were carried out to look at the impact of changes in vegetation characteristics (specifically of leaves) on litter decomposition, and how these influence near term litter decomposition rates (k values) and long-term SOC content of the soil system beneath. Leaves of teak, bamboo and eight other species were selected for this study. The proportion of structural carbohydrates (lignin and cellulose) in leaves significantly (at 5 % level) influenced k values. The SOC and carbon isotope data collected in this study indicate that C3 vegetation cover in the study area could be contemporary and dominant for the past few centuries. This can be extended up to ~2,200 years from the recorded 14C values of teak cover. The study confirms that k values of leaf litter influence SOC present beneath the vegetation cover at the decadal/century time scale.
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... Changes in aboveground litter production will have a direct impact on belowground processes (Sayer et al. 2007;Tian et al. 2010;Demessie et al. 2012;Uriarte et al. 2015). Thus, the build-up of SOC and release of nutrients in soils is a dynamic balance between both above (net primary production i.e., in terms of quality and quantity of litterfall) and belowground litter inputs and organic matter outputs (loss through decomposition) in the form of CO 2 efflux (Tian et al. 2010;Mehta et al. 2013). Soils may sequester more carbon when the decay rates is slow (Mehta et al. 2013) or inputs of organic matter from plants such as leaf litterfall increase (Chenu et al. 2019). ...
... Thus, the build-up of SOC and release of nutrients in soils is a dynamic balance between both above (net primary production i.e., in terms of quality and quantity of litterfall) and belowground litter inputs and organic matter outputs (loss through decomposition) in the form of CO 2 efflux (Tian et al. 2010;Mehta et al. 2013). Soils may sequester more carbon when the decay rates is slow (Mehta et al. 2013) or inputs of organic matter from plants such as leaf litterfall increase (Chenu et al. 2019). ...
... In semi-arid regions, the litter of the ground vegetation is seen as an important source of SOM (Shen et al. 2014). Maintenance of natural forest ecosystems is achieved by the circulation of nutrients through the litterfall and decomposition (Mehta et al. 2013). Litter accumulation and subsequently total SOC can increase with increasing restoration age (Descheemaeker et al. 2006;George et al. 2010). ...
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Background Litterfall input and associated nutrient flux are critically important in the restoration of soil in degraded landscapes through exclosures. This study was conducted to evaluate the effects of exclosure on seasonal litterfall production and nutrient content, and estimate annual C and N inputs to the soil in an age sequence at Kewet district, central lowland of Ethiopia. Leaf litterfall production was recorded by a 0.25 m² litter trap from a systematically laid line transects from 5, 15, and 20 years old exclosures and adjacent grazing land. Results Leaf litterfall input in the exclosures ranged from 37 g m⁻² in January (at the old exclosure) to 7.33 g m⁻² (at the young exclosure), and 3 g m⁻² in March at the grazing land. Litterfall input showed seasonal variation and peaked in the dry months. Mean monthly leaf litterfall production was significantly (p <0.05) higher (22 g m⁻²) in the old exclosure than the adjacent grazing land (9 g m⁻²). Total annual leaf litterfall ranged from 1073 kg ha⁻¹ (grazing land) to 2662 kg ha⁻¹ (old exclosure). There were no significant differences in leaf litterfall nutrients i.e., N, P, K, Ca, and Mg concentrations, except for C. The annual leaf litterfall associated C and N input ranged from 412 (grazing land) to 1025 (old exclosure) and 27 (middle age exclosure) to 68 kg ha⁻¹ (old exclosure), respectively. The positive change recorded in leaf litterfall production and associated C and N return is associated with restoration of vegetation. Conclusions Through well-managed area exclosure, leaf litterfall production in the degraded landscapes can reach the level of tropical dry lowland forest in about a decade. Further research on the contribution of dominant tree species in litter production along the age of exclosure is recommended to improve the effectiveness of rehabilitation of degraded lands.
... The trees vegetation in agroforestry could produce a substantial amount of leaf litter (Table 1) which becomes an important source of soil organic carbon and nutrients (Ampitan et al. 2021;Ledo et al. 2020;Sauvadet et al. 2020;McGrath et al. 2000;Mehta et al. 2013;Mutshekwa et al. 2020). Whilst soil organic carbon improves soil porosity and water percolation, the increased amount of available nutrient in soil improve growth and production of the crop (Shaxson & Barber 2003;Sanz et al. 2017). ...
... Litterfall and litter decomposition are key elements of nutrient cycling in tropical forests (Cole et al. 2020;Froufe et al. 2020;Castellanos-Barliza et al. 2018;Mehta et al. 2013). Before providing crop plants with nutrients, the leaf litter produced by trees in plantations undergo a complex interaction with soil involving biotic and abiotic factors (Keller & Phillips 2019). ...
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Indonesia is the second-largest vanilla production and the third-largest cocoa production in the world, but it sustained for a short period. The unsustainability of these crops is speculated to occur because of the change in leaf litter accumulation which affected the sustainability of soil organic carbon that plays an important role in maintaining soil health and fertility. To find out methods that could improve the sustainability of the production, a literature review was conducted. The articles, related to the sustainability of vanilla and cacao production, were collected using Google Scholar, Wiley Online Library, ResearchGate, and Google Chrome brows-er. Keywords were employed to find the articles including soil organic carbon, cocoa plantation, vanilla, leaf litter, and allelochemical. This current article review found that introducing crop by clearing of previously existing vegetation could severely reduce the rate of leaf litter accumulation. Consequently, in a prolonged period, the soil organic carbon and soil fertility are very low and are unable to support the healthy growth and production of the crops. To restore production, the plantation then is returned to more traditional agroforestry such as replanting shading trees and addition of mulch. However, in the higher density of canopy, the crop production is low attributed partly to the decreasing soil pH which increases the impact of allelochemical. This review concluded that the sustainability of leaf litter accumulation is crucial to maintain soil health, but mitigation is required to reduce the impact of allelochemical accumulation.
... Leaf litter is a predominant fraction of the organic fraction of the municipal solid waste, and leaf litter constitutes almost 35% of the overall waste collected at many locations [1]. Usually, the leaf litter is composted [2], and leaf decomposition is one of the major factors either in the case of composting or degradation towards biogas production. Leaves have the potential to produce twice as much as produced by cow dung [3]. ...
... Leaves have the potential to produce twice as much as produced by cow dung [3]. Leaves could be thin and easily decomposable or could be highly recalcitrant having lower photosynthetic rates [2]. Studies on certain varieties of available leafy biomass feedstock have been carried out with some success [4]. ...
... (3) taking an average of observed (O) parameters from sampling plots; and (4) using default (D) values. In literature, we were able to find some site-specific related parameters from Pandey and Brown (2000); Gangopadhyay (2005); Gopalakrishnan et al. (2011); Mehta et al. (2012); and Behera et al. (2017Behera et al. ( , 2019. Most of the parameters related to biomass partitioning, root turnover, and stem height were estimated from modelled values fitted to observed data. ...
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Key message Teak ( Tectona grandis L. f.) is a native tree species of India. It is one of the most desirable timber species because of its strength, fine texture, and durability. Its growth is strongly dependent on the climatic conditions, but empirical data are often unavailable to support management decisions. The physiological principles for predicting growth incorporated in the 3-PGmix model make it a useful tool in modelling the growth responses and management in the changing climate. We assessed that under elevated atmospheric carbon dioxide (CO 2 ) concentration and no thinning, teak would store more carbon than currently. ContextUncertainty and lack of scientific understanding about the growth response to climate change and thinning regimes have created challenges in teak sustainability, both regionally and globally.AimsThis research examines climate change and management implications on teak growth in India using the 3-PGmix model.Methods The 3-PGmix model was coupled with climate scenarios (Representative Concentration Pathway (RCP) 4.5 and 8.5) to forecast growth response up to the year 2100 with 1981–2010 as the baseline under thinning (G-quality, P-quality) regimes. Thinning under G-quality is performed at earlier stand age than P-quality, and then simulations under ‘no thinning’ based on stocking/ha at different thinning intensity.ResultsUnder ‘no thinning’, predicted net primary productivity (NPP) for RCP4.5 and RCP8.5 became 5.77 t/ha/year and 5.28 t/ha/year in 2100. However, under increasing CO2, it became 7.39 t/ha/year and 8.22 t/ha/year respectively in 2100. In the future, increasing CO2 would be the dominating factor for an increase in teak growth; however, abnormal precipitation and warmer temperature could produce an unforeseen growth condition. The carbon stock and CO2 sequestration are predicted to be higher under no thinning, which signifies the CO2 fertilisation effect in teak.Conclusion The set of parameters used in 3-PGmix offers an opportunity to predict teak responses to future climatic conditions and management treatments.
... Third, the degradation-induced turnover of species composition, for example, the ongoing replacement of grasses by ruderal species during grassland degradation, can affect the fixed soil C content (Wu et al., 2014;Han et al., 2018). Finally, changes in litter can have important effects on the variation of SOC (Mehta et al., 2013) and STN (Che et al., 2018). Specifically, degradation reduces the C and nitrogen (N) storage by changing the quantity and quality of litter input to the soil (Sun et al., 2018a). ...
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Understanding the effects of degradation on belowground biomass (BGB) is essential for assessment of carbon budget of the alpine meadow ecosystem on the Tibetan Plateau, China. This ecosystem has been undergoing serious degradation owing to climate change and anthropogenic activities. This study examined the response of the vertical distribution of plant BGB to degradation and explored the underlying mechanisms in an alpine meadow on the Tibetan Plateau. A field survey was conducted in an alpine meadow with seven sequential degrees of degradation in the Zoige Plateau on the Tibetan Plateau during the peak growing season of 2018. We measured aboveground biomass (AGB), BGB, soil water content (SWC), soil bulk density (SBD), soil compaction (SCOM), soil organic carbon (SOC), soil total nitrogen (STN), soil total phosphorus (STP), soil available nitrogen (SAN), and soil available phosphorus (STP) in the 0-30 cm soil layers. Our results show that degradation dramatically decreased the BGB in the 0-10 cm soil layer (BGB 0-10) but slightly increased the subsoil BGB. The main reason may be that the physical-chemical properties of surface soil were more sensitive to degradation than those of subsoil, as indicated by the remarked positive associations of the trade-off value of BGB 0-10 with SWC, SCOM, SOC, STN, SAN, and STP, as well as the negative correlation between the trade-off value of BGB 0-10 and SBD in the soil layer of 0-10 cm. In addition, an increase in the proportion of forbs with increasing degradation degree directly affected the BGB vertical distribution. The findings suggest that the decrease in the trade-off value of BGB 0-10 in response to degradation might be an adaptive strategy for the degradation-induced drought and infertile soil conditions. This study can provide theoretical support for assessing the effects of degradation on the carbon budget and sustainable development in the alpine meadow ecosystem on the Tibetan Plateau as well as other similar ecosystems in the world.
... Respiration could produce CO 2 with a wide range of δ 13 C values, because of large intraand inter-inhomogeneity between species. For example, soil and plant respired CO 2 fall in the range of À19 to À32 ‰ with an average of À27 ‰ for C 3 type of vegetation, and the values are À9 to À19 ‰ with an average of À13 ‰ for C 4 type (Deines, 1980;Laskar et al., 2013Laskar et al., , 2016cMehta et al., 2013). It is to be noted that the δ 13 C values of CO 2 originated from C 3 type plant respiration is indistinguishable from that emitted by fossil fuel combustion. ...
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... While the phosphorous content near fertilizer industry was high, it was low near thermal power plant. This is similar to results reported by other studies (Bhattacharyya et al., 2000;Falkengren-Grerup et al., 2006;Leaflets et al., 2013;Mehta et al., 2013;Post and Kwon, 2000;Ramachandran and Radhapriya, 2016). ...
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... While the phosphorous content near fertilizer industry was high, it was low near thermal power plant. This is similar to results reported by other studies (Bhattacharyya et al., 2000;Falkengren-Grerup et al., 2006;Leaflets et al., 2013;Mehta et al., 2013;Post and Kwon, 2000;Ramachandran and Radhapriya, 2016). ...
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Soil is a source of food and habitation for all terrestrial organisms and provides innumerable ecosystem services. However, it is a finite resource as it is not renewable on a human time scale. Land-use change drastically alters soil characteristics and increased soil carbon emissions. In this study, an effort has been made to assess soil characteristics in different land-use classes of Gandhinagar district, Gujarat. Land-use land cover classification was done using digital interpretation method and 9 classes were mapped. Stratified random sampling approach was adopted to obtain composite samples from 4 sites in 6 out of 9 land-use land cover classes from increasing depths of 0-10, 10-20 and 20-30 cm. Soil quality was assessed by testing pH, electrical conductivity, organic carbon, available phosphorous, potassium, and total nitrogen. It was found that vegetation class contained most fertile soil. The agriculture closely followed vegetation while urban showed least amount of soil organic carbon and other nutrients. Vegetation showed highest carbon and potassium levels while nitrogen and phosphorous were equally high in vegetation and agriculture class. Tree cover and the nature of land-use were crucial factors affecting soil health.
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