scholarly journals Temporal variation of soil organic carbon and total nitrogen stock and concentration along land use, species and elevation gradient of chilimo dry afromonate forest and adjacent land uses, ethiopia

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Mehari A. Tesfaye 1 ◽  
Andres Bravo Oviedo 2 ◽  
Felipe Bravo 3
Keyword(s):  
Land Use ◽  
Temporal Variation ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Soil Depth ◽  
Elevation Gradient ◽  
Native Forest ◽  
Carbon And Nitrogen ◽  
Nitrogen Stock ◽  
C And N

Forests play a vital role in the natural global carbon cycle by capturing carbon from the atmosphere through photosynthesis and converting it into forest biomass. Forests sequester and stores more carbon than any terrestrial ecosystem and act as sources as well as sinks of CO2. However, the increasing rate of deforestation and the impact of changes in land use require a critical and updated look at what is happening in the tropics. This work emphasized the temporal variation of bulk density, carbon (C) and nitrogen (N) stock and concentration in four land-use categories: natural forest, tree plantations, crop-land and degraded soil along elevation gradient and soil depth. The study was conducted in the Central Highlands of Ethiopia, where deforestation and human pressure on native forests are exacerbated and erosion has caused extensive soil loss. We hypothesized that, there is temporal variation of C and N concentrations and stocks in native forest along elevation gradient, land use type, species and soil depth. Carbon and N concentrations and stock and bulk densities in mineral soil were analysed as repeated measures in an irregular vertical space ranging from 0–10 cm, 10–30 cm, 30–50 cm and 50–100 cm, using a linear mixed model approach in two-time scale period 2012 - 2017. Double observations in 2012 and 2017, were made from the forest floor were analysed by a general linear mixed model. There is significant variation in organic carbon and nitrogen stock along elevation gradient for forest floor. Results also indicated that soil depth is more important factor than elevation gradient in native forests, though C and N concentrations and stocks diminished near human settlements. Native forest stored on average more nitrogen than bare soil, cropland and plantations, respectively. Conversion of crop and degraded land into plantations ameliorated soil degradation conditions, but species selection did not affect carbon and nitrogen stocks. Thus, appropriate forest management options should be applied in order to increase productivity and carbon sink of Chilimo dryafromontane forest and adjacent land use. Temporal monitoring and reporting of carbon stock and concentration is also important to understand the role of Chilimo dryafromonate forest in climate change mitigation and adaptation agendas.

scholarly journals Combined deep sampling and mass-based approaches to assess soil carbon and nitrogen losses due to land-use changes in karst area of Southwestern China

2016 ◽  
Author(s):  
Yecui Hu ◽  
Zhangliu Du ◽  
Qibing Wang ◽  
Guichun Li
Keyword(s):  
Land Use ◽  
Land Use Changes ◽  
Soil Mass ◽  
Karst Area ◽  
Southwestern China ◽  
Native Forest ◽  
Eucalyptus Plantation ◽  
Carbon And Nitrogen ◽  
Managed Ecosystems ◽  
Effect Magnitude

Abstract. The conversion of natural vegetation to managed ecosystems may negatively influence soil organic carbon (SOC) and total nitrogen (TN) stocks, particularly in the fragile ecosystems. The objective of present study was to assess SOC and TN stocks losses by combining deep sampling with mass-based calculations upon land-use changes in a typical karst area of Southwestern China. We quantified the changes from native forest to grassland, secondary shrub, eucalyptus plantation, sugarcane and corn fields (both defined as croplands), on the SOC and TN stocks down to 100 cm depth using fixed-depth (FD) and equivalent soil mass (ESM) approaches. The results showed that converting forest to cropland and other types significantly led to SOC and TN losses, although the effect magnitude partly depended on both sampling depths and soil mass considered. On average, the shifting from native forest to cropland led to SOC losses by 19.1 %, 25.1 %, 30.6 %, 36.8 % and 37.9 % for the soil depths of 0–10, 0–20, 0–40, 0–60 and 0–100 cm, respectively, which highlighted that shallow sampling underestimated SOC losses. Moreover, the FD method underestimated SOC and TN losses for the upper 40 cm layer, but overestimated the losses in the deeper profiles. We suggest that the ESM together with deep sampling should be encouraged to detect the differences in SOC stocks. In conclusion, the conversion of forest to managed systems, in particular croplands significantly decreased in SOC and TN stocks, although the effect magnitude to some extent depended on sampling depth and calculation approach selected.

scholarly journals Succession and the Relationship between Vegetation and Soil in the Marl Quarries of the Yucatan Peninsula, Mexico

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 116 ◽  
Author(s):  
Mirna Valdez-Hernández ◽  
Rossana Gil-Medina ◽  
Jorge O. López-Martínez ◽  
Nuria Torrescano-Valle ◽  
Nancy Cabanillas-Terán ◽  
...  
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Soil Depth ◽  
Yucatan Peninsula ◽  
Open Pit ◽  
Limiting Factors ◽  
Open Pit Mining ◽  
P Availability ◽  
Secondary Forests ◽  
Yucatán Peninsula

Open-pit mining is a common activity in the Yucatan Peninsula for the extraction of limestone. These areas are characterized by the total removal of the natural vegetation cover and soil in order to access calcareous material. The present study shows the composition and structure of the vegetation in five quarries after approximately ten years of abandonment, and the target vegetation near to the quarries in southeastern Mexico. A linear mixed model showed that P availability is one of the limiting factors for species establishment in the quarries. Using a canonical correspondence analysis (CCA), the distribution of the species was determined in relation to the edaphic variables: soil depth, the percentage of organic matter (OM), cationic exchange capacity (CEC), pH and texture. Twenty-six families, 46 genera and 50 species were recorded in the quarries, and 25 families, 45 genera and 47 species were recorded in the conserved areas. The dominant species in the quarries belong to the families Poaceae, Fabaceae, Rubiaceae and Anacardiaceae. The quarries with higher values of OM (2%), CEC (24 Cmol/kg), depth (11 cm) and sand percentage (31%) include the following species Lysiloma latisiliquum (L.) Benth., Metopium brownei (Jacq.) Urb. and Bursera simaruba (L.) Sarg., which are common in secondary forests. Quarries with lower values of OM (0.4%), CEC (17 Cmol/kg) and depth (5.02), and with a higher percentage of silt (42%) were dominated by herbs belonging to Poaceae and by Borreria verticillate (L.) G. Mey., which are typical in disturbed areas of southeastern Mexico. In all cases, the pH was slightly alkaline due to the content of calcium carbonate (CaCO3), characteristic of the soils of the region.

Deforestation and land use strongly effect soil organic carbon and nitrogen stock in Northwest Ethiopia

CATENA ◽  
2017 ◽  
Vol 153 ◽  
pp. 89-99 ◽  
Author(s):  
Dessie Assefa ◽  
Boris Rewald ◽  
Hans Sandén ◽  
Christoph Rosinger ◽  
Abrham Abiyu ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Northwest Ethiopia ◽  
Carbon And Nitrogen ◽  
Nitrogen Stock

Effects of land-use change and management on soil carbon and nitrogen in the Brigalow Belt, Australia: II. Statistical models to unravel the climate-soil-management interaction

2016 ◽  
Vol 38 (5) ◽  
pp. 453 ◽  
Author(s):  
M. J. Pringle ◽  
D. E. Allen ◽  
T. G. Orton ◽  
T. F. A. Bishop ◽  
D. W. Butler ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Carbon ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Regression Trees ◽  
Depth Interval ◽  
Native Vegetation ◽  
Δ13c And Δ15n ◽  
Organic C ◽  
The Impact

The impact of grazing on soil carbon (C) and nitrogen (N) cycles is complex, and across a large area it can be difficult to uncover the magnitude of the effects. Here, we have linked two common approaches to statistical modelling – regression trees and linear mixed models – in a novel way to explore various aspects of soil C and N dynamics for a large, semiarid bioregion where land use is dominated by grazing. The resulting models, which we term RT-LMM, have the pleasing visual appeal of regression trees, and they account for spatial autocorrelation as per a linear mixed model. Our RT-LMM were developed from explanatory variables that related information on climate, soil and past land management. Response variables of interest were: stocks of soil total organic carbon (TOC), soil total nitrogen (TN), and particulate organic C (POC); the ratio of TOC stock to TN stock; and the relative abundance of stable isotopes δ13C and δ15N in the soil. Each variable was sampled at the depth interval 0–0.3 m. The interactions of land use with, in particular, air temperature and soil phosphorus were strong, but three principal management-related effects emerged: (i) the use of fire to clear native vegetation reduced stocks of TOC and TN, and the TOC : TN ratio, by 25%, 19% and 9%, respectively, suggesting that TOC is more sensitive to fire than TN; (ii) conversion of native vegetation to pasture enriched soil with δ13C by 1.7 ‰; subsequent regrowth of the native vegetation among the pasture restored δ13C to its original level but there was no corresponding change in TOC stock; and, (iii) the time elapsed since clearing reduced POC stocks and the TOC : TN ratio.

Local environmental conditions affecting anuran tadpoles' microhabitat choice and morphological adaptation

2019 ◽  
Vol 70 (3) ◽  
pp. 395 ◽  
Author(s):  
N. C. S. Marques ◽  
L. Rattis ◽  
F. Nomura
Keyword(s):  
Land Use ◽  
Environmental Variables ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Vegetation Type ◽  
Fine Tuning ◽  
Mixed Model Approach ◽  
Generalised Linear Mixed Model ◽  
Vegetation Heterogeneity ◽  
Microhabitat Choice

In this study, we investigated the environmental variables that best explained tadpole occurrence, as well as associations between environmental variables and the morphological traits of tadpoles. We modelled the occurrence of tadpoles to evaluate the significance of trait–environment relationships by sampling in 86 ponds, measuring a set of environmental descriptors of these ponds, determining the tadpoles’ external-morphology changes and using a generalised linear mixed model approach. The best fitting model predicting tadpole occurrence included all the environmental variables measured (pond dimensions, pond margin type, pond bottom substrate, vegetation type inside the pond, vegetation type in the pond margins, landscape descriptors) and seven morphology–environment interactions. Tadpoles are capable of fine-tuning their morphology according to the environmental traits of the pond and land use changes around the pond. Vegetation heterogeneity of ponds interacts with tadpole morphology primarily on tail size and deviations in the mean position of the eye, nostril and mouth. Moreover, there are increases in body size and tail length in smaller ponds, as well as in ponds surrounded vegetation changes from forest to pasture or short crops. Changes in environmental variables as a result of land use change can affect the dispersion of adult frogs and, consequently, the occurrence of and morphological variations in tadpoles. Local environmental variables play important roles driving tadpoles’ microhabitat choice; once tadpoles cannot select the site of their developmental, they need to compensate for any mismatching by induced morphological adaptations.

Estimating Traffic Volume for Local Streets with Imbalanced Data

2019 ◽  
Vol 2673 (3) ◽  
pp. 598-610 ◽  
Author(s):  
Peng Chen ◽  
Songhua Hu ◽  
Qing Shen ◽  
Hangfei Lin ◽  
Chi Xie
Keyword(s):  
Land Use ◽  
Traffic Engineering ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Model Performance ◽  
Imbalanced Data ◽  
Spillover Effects ◽  
Traffic Monitoring ◽  
Estimation Accuracy ◽  
Road Segments

Annual average daily traffic (AADT) is an important measurement used in traffic engineering. Local streets are major components of a road network. However, automatic traffic recorders (ATRs) used to collect AADT are often limited to arterial roads, and such information is, therefore, often unavailable for local streets. Estimating AADT on local streets becomes a necessity as local street traffic continues to grow and the capacity of arterial roads becomes insufficient. A challenge is that an under-represented sample of local street AADT may result in biased estimation. A synthetic minority oversampling technique (SMOTE) is applied to oversample local streets to correct the imbalanced sampling among different road types. A generalized linear mixed model (GLMM) is employed to estimate AADT incorporating various independent variables, including factors of roadway design, socio-demographics, and land use. The model is examined with an AADT dataset from Seattle, WA. Results show that: (1) SMOTE helps to correct imbalanced sampling proportions and improve model performance significantly; (2) the number of lanes and the number of crosswalks are both positively associated with AADT; (3) road segments located in areas with a higher population density or more mixed land use have a higher AADT; (4) distance to the nearest arterial road is negatively correlated with AADT; and (5) AADT creates spatial spillover effects on neighboring road segments. The combination of SMOTE and GLMM improves the estimation accuracy on AADT, which contributes to better data for transportation planning and traffic monitoring, and to cost saving on data collection.

Effects of land-use change and management on soil carbon and nitrogen in the Brigalow Belt, Australia: I. Overview and inventory

2016 ◽  
Vol 38 (5) ◽  
pp. 443 ◽  
Author(s):  
D. E. Allen ◽  
M. J. Pringle ◽  
D. W. Butler ◽  
B. K. Henry ◽  
T. F. A. Bishop ◽  
...  
Keyword(s):  
Land Use ◽  
Native Forest ◽  
Land Resource ◽  
Total N ◽  
Organic C ◽  
Soil C ◽  
Forest Regrowth ◽  
Forest Remnant ◽  
C And N ◽  
The Difference

Soil and land-management interactions in Australian native-forest regrowth remain a major source of uncertainty in the context of the global carbon economy. We sampled soil total organic C (TOC) and soil total N (TN) stocks at 45 sites within the Brigalow ecological community of the Brigalow Belt bioregion, Queensland, Australia. The sites were matched as triplets representing three land uses, specifically: uncleared native brigalow forest (‘Remnant’); grassland pasture (‘Pasture’), derived by clearing native vegetation and maintained as pasture for a minimum of 10 years, and; regrowing native brigalow forest (‘Regrowth’, stand ages ranging from 10 to 58 years) that had developed spontaneously after past vegetation clearing for pasture establishment. Soil TOC fractions and natural abundance of soil C and N isotopes were examined to obtain insight into C and N dynamics. An updated above- and belowground carbon budget for the bioregions was generated. Average soil TOC stocks at 0–0.3-m depth ranged from 19 to 79 Mg ha–1 and soil TN stocks from 1.8 to 7.1 Mg ha–1 (2.5th and 97.5th percentiles, respectively). A trend in stocks was apparent with land use: Remnant > Regrowth ≅ Pasture sites. Soil δ13C ranged from –14 to –27‰, and soil δ15N ranged from 4‰ to 17‰, in general reflecting the difference between Pasture (C4-dominated) land use and N2-fixing (C3-dominated) Remnant and Regrowth. Mid-infrared spectroscopy predicted C fractions as a percentage of soil TOC stock, which ranged from 5% to 60% (particulate), 20–80% (humus) and 9–30% (resistant/inert). The geo-referenced soil and management information we collected is important for the calibration of C models, for the estimation of national C accounts, and to inform policy developments in relation to land-resource management undertaken within the Brigalow Belt bioregions of Australia.

scholarly journals Distribution of Carbon and Nitrogen and Ecological Stoichiometry of the Plant-Litter-Soil Continuum in an Evergreen Broad-Leaved Forest

2018 ◽  
Author(s):  
Hui Wang ◽  
Bing Wang ◽  
Xiang Niu ◽  
Qingfeng Song ◽  
Haonan Bai ◽  
...  
Keyword(s):  
Fine Roots ◽  
Ecological Stoichiometry ◽  
Soil Depth ◽  
Plant Litter ◽  
N Content ◽  
Total N ◽  
Carbon And Nitrogen ◽  
Broad Leaved Forest ◽  
C And N ◽  
Leaved Forest

We analyzed the plant-litter-soil continuum to investigate the carbon and nitrogen distribution and ecological stoichiometry of an evergreen broad-leaved forest at Dagangshan Mountain, Jiangxi. The results showed that the average C and N contents and C:N ratios in the leaves and fine roots among 6 different tree species were 401.87g/kg, 21.41g/kg, 19.27 and 348.64g/kg, 15.73g/kg, 23.97, respectively; the average C and N contents and C:N ratios were 323.06 g/kg, 12.76 g/kg, 25.58 respectively in leaf litter, and 16.40 g/kg, 1.09 g/kg, 16.27 respectively for soil. In contrast with the C content, the total N content of the fine roots and litter had a high coefficient of variation and a high spatial heterogeneity. We ranked the six different representative tree species according to total C and N content in leaves and fine roots. The results for each species were generally consistent with each other, showing a positive correlation relationship between total C and N content in the leaves and roots. Among them, S. discolor (Champ. ex Benth.) Muell. plants displayed high carbon and nitrogen storage capacities, and on the other hand, C. fargesii Franch., C. myrsinifolia (Blume) Oersted, A. fortunei (Hemsl.) Makino, and V. fordii (Hemsl.) Airy Shaw showed a high nitrogen transfer rate. Total soil N and C decreased with depth. Soil organic carbon (SOC), soil resistant organic carbon (ROC), total N, alkali nitrogen, NH4+-N and NO3--N contents were all also negative correlated with soil depth, but the contents of the NH4+-N and NO3--N did not change significantly; The spatial distribution of soil NO3--N was significantly heterogeneous. At 0-10 cm soil depth, SOC was positively correlated with alkaline nitrogen, and at 10-20 cm soil depth, SOC was significantly positively correlated with total N. In general, when soil carbon was abundant, nitrogen supply capacity was also high.

scholarly journals Land use influences microbial biomass carbon, organic carbon and nitrogen stock in a tropical acric luvisols of Southwestern Nigeria

2016 ◽  
Vol 3 (6) ◽  
pp. 413-423
Author(s):  
Segun Oluwatomiwa Oladele ◽  
Adebayo Jonathan Adeyemo
Keyword(s):  
Land Use ◽  
Microbial Biomass ◽  
Organic Carbon ◽  
Oil Palm ◽  
Microbial Biomass Carbon ◽  
Fallow Land ◽  
Biomass Carbon ◽  
Southwestern Nigeria ◽  
Carbon And Nitrogen ◽  
Nitrogen Stock

A study was conducted to determine the effect of different land use on microbial biomass carbon, organic carbon and nitrogen stock on a tropical acric luvisols at Ibadan, Oyo State, Southwestern Nigeria. Soil samples were collected in 2014 using a quadrant approach across ten plots at the surface (0-15 cm) and sub-surface (16-30 cm) depths in four different land use systems of (i) 8-year old citrus, (ii) 8 year old cacao, (iii) 8 year oil palm and (iv) a fallow land of over 25 years. Significant differences in soil physical and chemical properties, microbial biomass carbon, carbon and nitrogen stock in different land use types at two depths (0-15 and 15-30 cm) were observed on soil properties important for sustainable crop production. Fallow land use, oil palm plantation and cocoa plantation were characterized by higher carbon and nitrogen stock, microbial biomass carbon, total nitrogen, organic carbon, available phosphorus, marginally low exchangeable bases except for Ca and Mg with relatively higher values and marginal C/N ratio. These land use also had lower bulk density, high total porosity, high moisture content and optimum soil temperature level. These results suggest that incorporation of optimum fallow cycle with appropriate land use in combination with soil enriching cover and tree crops in the study area will increase carbon and nitrogen stock while imitating a forest ecosystem condition which would help restore soil fertility in degraded lands while reducing greenhouse gas fluxes.

scholarly journals Land-Use Effect on Soil Carbon and Nitrogen Stock in a Seasonally Dry Tropical Forest

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 158
Author(s):  
Eunice Maia Andrade ◽  
Wilner Valbrun ◽  
Aldênia Mendes Mascena de Almeida ◽  
Gilberto Rosa ◽  
Antonio Givanilson Rodrigues da Silva
Keyword(s):  
Land Use ◽  
Soil Degradation ◽  
Soil Samples ◽  
Land Uses ◽  
Carbon And Nitrogen ◽  
Seasonally Dry ◽  
Nitrogen Stock ◽  
Significant Difference ◽  
Dry Tropical Forests ◽  
Semi Arid Region

Total organic carbon (TOC) and total nitrogen (TN) concentration in the soil are an indicator of soil degradation. To understand how land-use may impact these concentrations in seasonally dry tropical forests (SDTF), we analyzed the effect of four land-uses on TOC stocks (STK.TOC) and TN stocks (STK.TN) in a semi-arid region of Brazil. Soil samples were collected in 12 trenches (three sites × four land-uses—dense caatinga (DC), open caatinga (OC), pasture (PA) and agriculture (AG)), in the 0–10; 10–20 and 20–30 cm layers or as far as the bedrock. The data were compared by the Kruskal–Wallis test (p ≤ 0.05) and similarity investigated by cluster analysis. STK.TOC and STK.TN the surface layer (0–10 cm) showed no significant difference (p ≤ 0.05) between the DC; OC and PA land-uses. The similarity in STK.TOC and STK.TN values between DC, OC and PA, indicate that it is possible to explore SDTF to produce biomass and protein by adopting open caatinga and pasture land uses on Neosols with very low TOC stocks. The greatest reduction in STK.TOC and STK.TN in the agriculture land-use may lead to soil degradation and contribute to the addition of CO2 to the atmosphere.

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