The effects of land management (grazing intensity) vs. the effects of topography, soil properties, vegetation type, and climate on soil carbon concentration in Southern Patagonia

Soil properties are strongly influenced by the composition of the surrounding vegetation. We investigated soil properties of three ecosystems; a coniferous forest, a deciduous forest and an agricultural grassland, to determine the impact of land use change on soil properties. Disturbances such as deforestation followed by cultivation can severely alter soil properties, including losses of soil carbon. We collected nine 40 cm cores from three ecosystem types on the Roebuck Farm, north of Perth Village, Ontario, Canada. Dominant species in each ecosystem included hemlock and white pine in the coniferous forest; sugar maple, birch and beech in the deciduous forest; grasses, legumes and herbs in the grassland. Soil pH varied little between the three ecosystems and over depth. Soils under grassland vegetation had the highest bulk density, especially near the surface. The forest sites showed higher cation exchange capacity and soil moisture than the grassland; these differences largely resulted from higher organic matter levels in the surface forest soils. Vertical distribution of organic matter varied greatly amongst the three ecosystems. In the forest, more of the organic matter was located near the surface, while in the grassland organic matter concentrations varied little with depth. The results suggest that changes in land cover and land use alters litter inputs and nutrient cycling rates, modifying soil physical and chemical properties. Our results further suggest that conversion of forest into agricultural land in this area can lead to a decline in soil carbon storage.

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Subsoil organic carbon turnover is dominantly controlled by soil properties in grasslands across China

10.5194/egusphere-egu21-2413 ◽

2021 ◽

Author(s):

Yuehong Shi ◽

Xiaolu Tang ◽

Peng Yu ◽

Li Xu ◽

Guo Chen ◽

...

Keyword(s):

Climate Change ◽

Organic Carbon ◽

Soil Properties ◽

Soil Carbon ◽

Carbon Turnover ◽

Area Index ◽

Important Indicator ◽

Environmental Controls ◽

Biogeochemical Models ◽

Soc Stock

<p>Soil carbon turnover time (&#964;, year) is an important indicator of soil carbon stability, and a major factor in determining soil carbon sequestration capacity. Many studies investigated &#964; in the topsoil or the first meter underground, however, little is known about subsoil &#964; (0.2 &#8211; 1.0 m) and its environmental drivers, while world subsoils below 0.2 m accounts for the majority of total soil organic carbon (SOC) stock and may be as sensitive as that of the topsoil to climate change. We used the observations from the published literatures to estimate subsoil &#964; (the ratio of SOC stock to net primary productivity) in grasslands across China and employed regression analysis to detect the environmental controls on subsoil &#964;. Finally, structural equation modelling (SEM) was applied to identify the dominant environmental driver (including climate, vegetation and soil). Results showed that subsoil &#964; varied greatly from 5.52 to 702.17 years, and the mean (&#177; standard deviation) subsoil &#964; was 118.5 &#177; 97.8 years. Subsoil &#964; varied significantly among different grassland types that it was 164.0 &#177; 112.0 years for alpine meadow, 107.0 &#177; 47.9 years for alpine steppe, 177.0 &#177; 143.0 years for temperate desert steppe, 96.6 &#177; 88.7 years for temperate meadow steppe, 101.0 &#177; 75.9 years for temperate typical steppe. Subsoil &#964; significantly and negatively correlated (p < 0.05) with vegetation index, leaf area index and gross primary production, highlighting the importance of vegetation on &#964;. Mean annual temperature (MAT) and precipitation (MAP) had a negative impact on subsoil &#964;, indicating a faster turnover of soil carbon with the increasing of MAT or MAP under ongoing climate change. SEM showed that soil properties, such as soil bulk density, cation exchange capacity and soil silt, were the most important variables driving subsoil &#964;, challenging our current understanding of climatic drivers (MAT and MAP) controlling on topsoil &#964;, further providing new evidence that different mechanisms control topsoil and subsoil &#964;. These conclusions demonstrated that different environmental controls should be considered for reliable prediction of soil carbon dynamics in the top and subsoils in biogeochemical models or earth system models at regional or global scales.</p>

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Agro-forestry Systems as a Means to Achieve Carbon Co-benefits in Nepal

Journal of Forest and Livelihood ◽

10.3126/jfl.v13i1.15366 ◽

2016 ◽

Vol 13 (1) ◽

pp. 59-68

Author(s):

Roshan M. Bajracharya ◽

Him Lal Shrestha ◽

Ramesh Shakya ◽

Bishal K. Sitaula

Keyword(s):

Organic Carbon ◽

Soil Properties ◽

Soil Carbon ◽

Bulk Density ◽

Agricultural Land ◽

Carbon Stocks ◽

Community Forests ◽

C Stocks ◽

Soil Carbon Stocks ◽

Agro Forestry

Land management regimes and forest types play an important role in the productivity and accumulation of terrestrial carbon pools. While it is commonly accepted that forests enhance carbon sequestration and conventional agriculture causes carbon depletion, the effects of agro-forestry are not well documented. This study investigated the carbon stocks in biomass and soil, along with the selected soil properties in agro-forestry plots compared to community forests (CF) and upland farms in Chitwan, Gorkha and Rasuwa districts of Central Nepal during the year 2012-2013. We determined the total above ground biomass carbon, soil organic carbon (SOC) stocks and soil properties (bulk density, organic carbon per cent, pH, total nitrogen (TN), available phosphorus (P), exchangeable potassium (K), and cation exchange capacity (CEC)) on samples taken from four replicates of 500 m2 plots each in community forests, agro-forestry systems and agricultural land. The soil was sampled in two increments at 0-15 cm and 15-30 cm depths and intact cores removed for bulk density and SOC determination, while loose samples were separately collected for the laboratory analysis of other soil properties. The mean SOC percent and corresponding soil carbon stocks to 30 cm depth were generally highest in CF (3.71 and 3.69 per cent, and 74.98 and 76.24 t ha-1, respectively), followed by leasehold forest (LHF) (2.26 and 1.13 per cent and 40.72 and 21.34 t ha-1, respectively) and least in the agricultural land (3.05 and 1.09 per cent, and 63.54 and 19.42 t ha-1, respectively). This trend was not, however, observed in Chitwan, where agriculture (AG) had the highest SOC content (1.98 per cent) and soil carbon stocks (42.5 t ha-1), followed by CF (1.8 per cent and 41.2 t ha-1) and leasehold forests (1.56 per cent and 35.3 t ha-1) although the differences were not statistically significant. Other soil properties were not significantly different among land use types with the exceptions of pH, total N, available P and CEC in the Chitwan plots. Typically, SOC and soil carbon stocks (to 30cm depth) were positively correlated with each other and with TN and CEC. The AGB-C was expectantly highest in Rasuwa district CF (ranging from 107.3 to 260.3 t ha-1) due to dense growth and cool climate, followed by Gorkha (3.1 to 118.4 t ha-1), and least in Chitwan (17.6 to 95.2 t ha-1). The highest C stocks for agro-forestry systems in both above ground and soil were observed in Rasuwa, followed by Chitwan district. Besides forests, agro-forestry systems also hold good potential to store and accumulate carbon, hence they have scope for contributing to climate change mitigation and adaptation with co-benefits.Journal of Forest and Livelihood 13(1) May, 2015, page: 56-68

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The effects of sealing on urban soil carbon and nutrients

SOIL ◽

10.5194/soil-7-661-2021 ◽

2021 ◽

Vol 7 (2) ◽

pp. 661-675

Author(s):

Roisin O'Riordan ◽

Jess Davies ◽

Carly Stevens ◽

John N. Quinton

Keyword(s):

Ecosystem Services ◽

Soil Properties ◽

Soil Carbon ◽

Urban Soil ◽

Green Space ◽

Great Influence ◽

Nitrate Content ◽

Soil Functions ◽

Soil Sealing ◽

Nutrient Stocks

Abstract. Urban soils are of increasing interest for their potential to provide ecosystem services such as carbon storage and nutrient cycling. Despite this, there is limited knowledge on how soil sealing with impervious surfaces, a common disturbance in urban environments, affects these important ecosystem services. In this paper, we investigate the effect of soil sealing on soil properties, soil carbon and soil nutrient stocks. We undertook a comparative survey of sealed and unsealed green space soils across the UK city of Manchester. Our results reveal that the context of urban soil and the anthropogenic artefacts added to soil have a great influence on soil properties and functions. In general, sealing reduced soil carbon and nutrient stocks compared to green space soil; however, where there were anthropogenic additions of organic and mineral artefacts, this led to increases in soil carbon and nitrate content. Anthropogenic additions led to carbon stocks equivalent to or larger than those in green spaces; this was likely a result of charcoal additions, leading to carbon stores with long residence times. This suggests that in areas with an industrial past, anthropogenic additions can lead to a legacy carbon store in urban soil and make important contributions to urban soil carbon budgets. These findings shed light on the heterogeneity of urban sealed soil and the influence of anthropogenic artefacts on soil functions. Our research highlights the need to gain a further understanding of urban soil processes, in both sealed and unsealed soils, and of the influence and legacy of anthropogenic additions for soil functions and important ecosystem services.

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Impacts of reindeer grazing on soil properties on Finnmarksvidda, northern Norway

Rangifer ◽

10.7557/2.24.4.1726 ◽

2004 ◽

pp. 83-91 ◽

Cited By ~ 2

Author(s):

Christian Uhlig ◽

Tore E. Sveistrup ◽

Ivar Schjelderup

Keyword(s):

Soil Fertility ◽

Soil Properties ◽

Plant Cover ◽

Grazing Intensity ◽

Organic Layer ◽

Organic C ◽

Northern Norway ◽

Available Water ◽

Lichen Cover ◽

Plant Available Water

Numerous investigations have documented changes in vegetation due to reindeer grazing in Finnmark County, Northern Norway. However, rather few studies have focused on impacts of reindeer grazing on soil properties. The aim of this investigation was to identify possible changes in physical and chemical soil properties due to reindeer grazing. Furthermore, root distribution was detected. At four different locations on Finnmarksvidda three sample sites each were selected subjectively according to lichen and plant cover: A) ample, B) reduced, and C) poor lichen and plant cover. It was supposed that differences in lichen and plant cover were due to differences in reindeer grazing intensity. Results showed that the organic layer beneath ample lichen cover had an about 20% higher CEC and a 30—50% higher concentration of plant available Ca and Mg and total Mg compared to those beneath reduced ones. At sites with poor lichen and plant cover, an organic layer was mostly missing. The exposed mineral Eh-horizons at these sites had a significant (P<0.05) higher organic C content, higher CEC, concentrations of total P, Ca and K, and plant available K, when compared to E-horizons beneath better lichen covers. Rooting depth and amounts of plant available water in the rooting zone were lower at sites with reduced and poor lichen cover. A relation was found between soil organic C and CEC for all soil samples, indicating that soil organic matter is an essential key factor for soil fertility at the investigate sites on Finnmarksvidda. Assuming that differences in lichen and plant cover are related to differences in grazing intensity, results indicate that overgrazing by reindeers can cause a significant degradation of the organic layer, followed by significant losses of essential plant nutrients, a reduction in plant available water and consequently soil fertility.

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