Grazing Land Use Research Articles

Impacts of land-use and topography on soil physicochemical properties in the Wamancho watershed, Southern Ethiopia

For sustainable land management, clear information that accounts for changes in land-use types and landscapes is essential. The purpose of this study was to examine how land-use patterns and topographic variation affect selected soil property indicators in the Wamancho watershed of the Damot Pulasa district in southern Ethiopia. Soil samples were obtained from the topography of three types of land use (agroforestry, cultivated land, and grazing area). At a depth of 20 cm, 27 soil samples were collected (three land use categories × three topographies × three replications). The collected soil samples were analyzed using standard laboratory procedures. The results showed that soil texture classes, such as sand and clay, bulk density, pH, SOC, Av. P, total N, CEC, and exchangeable bases, changed considerably (p < 0.05) with land use type, whereas total N, sand, and silt did not vary significantly with slope. Soil pH, SOC, Av. P, CEC, percentage of silt, and exchangeable cations (Na+, Mg2+, and K+) were found to be highest in agroforestry, while sand concentration was highest in cultivated land. Exchangeable Mg and K were found to be lower on cultivated ground, while Ca+ was found to be lower on agroforestry land. Finally, most soil quality indicators revealed a significant (p < 0.05) difference between agroforestry and grazing land use. Despite the fact that soil quality varies based on topography and land use type, local-level planning has not been conducted on a priority basis or in specific locations. As a result, all involved parties, including local governments, stakeholders, and planners, should develop effective site-based sustainable land management interventions, as they need to be addressed quickly, particularly on cultivated land, grazing land, and upper topography.

Grazing Land Productivity, Floral Diversity, and Management in a Semi-Arid Mediterranean Landscape

Most grazing lands in Mediterranean ecosystems that support extensive sheep farming systems are characterized by unfavorable edapho-climatic conditions, especially in semi-arid areas. Often, though, their use is far from sustainable, causing erosion and ecosystem degradation impacts. In this paper, we explore the use, productivity, and flora diversity of typical Mediterranean grazing lands in four farms at the Agra locality in the western part of Lesvos Island, Greece. For a period of two consecutive growing seasons (September to June), we recorded herbage biomass on 16 plots of grazing lands with three measurements per season of land cover and plant productivity (biomass) inside small exclosures (cages) protected from grazing. We recorded the species richness of herbaceous plant communities within and outside the cages at the end of every growing season, the period of maximum growth of herbaceous species. We also chemically analyzed the biomass for crude protein at the end of each season. Results show sizable productivity differences among pasture plots as well as seasons and an overall medium to high degree of productivity and species richness considering the relatively intensive grazing, with little differences over the different cages and the degree of grazing intensity. These results suggest that the “history” of the fields is important, as grazing lands that had been used for arable crops in the past, as well as those leveled and in favorable locations, were the most productive and diverse ones, while shallower soils and inclined grazing lands showed signs of overuse and degradation. Overall, though, these ecosystems showed a high degree of resilience despite their intensive use.

Forms and Dynamics of Soil Potassium in Acid Soil in the Wolaita Zone of Southern Ethiopia

Quantity-intensity (Q/I) characteristics are among conventional approaches for studying potassium dynamics and its availability. This was assessed to determine availability in four districts: namely, Sodo Zuria, Damot Gale, Damot Sore, and Boloso Sore, at three different land use systems (enset-coffee, crop land, and grazing land). Fractionation and dynamics of K sources were studied in soil samples, which were collected from 0–20 cm depth of each land system. The study revealed that water extractable K (H2O-K) concentrations ranged from 0.13 to 0.34 cmolc kg−1 soils at enset-coffee and grazing land use systems, respectively, and had a mean value of 0.28 cmolc kg−1 soils ammonium acetate extractable (NH4OAC-K) and nitric acid extract (HNO3-K) had a mean value of 0.25 cmolc kg−1 soils. In this study, the means of nonexchangeable- and exchangeable-K concentrations were of 0.11 and 0.14 cmolc kg−1 soils for land use types. Significant correlations were found between soil properties and Q/I parameters and among equilibrium solution parameters and Q/I parameters. There was no significant variation among the mean quantity values of the soils. The soils had higher change in exchangeable-K and potential buffering capacity than the enset-coffee land use soils, and the cop land had the highest values for these parameters. However, the enset-coffee land use soils had higher K-intensity. Therefore, application of site specific soil fertility management practices and research can improve soil K status and Q/I parameters to sustain productivity soils.

Land Use Changes and Their Effects on Soil Physical and Chemical Properties in Abol woreda Gambella Regional State

In Abol woreda continuous cultivation, intensive grazing and investment are the major practiced in the woreda soil without out intensive care was decline in soil chemical, biological and physical properties. The current research, therefore, is intended to determine Land use Changes and consequence on Soil Physicio-Chemical Properties in Abol woreda Gambella Regional State. General visual field observation and survey were carried out and the research site was portioned in to three major land uses (cropped grazing and forest land use types). Accordingly, a total of three major land uses (cultivated grazing and forest land use types) were identified in field based on soil texture and land use systems. Finally three major land use system were identified, and from each major site, composite soil samples were taken from thirteen soil sub-samples (spots) within one depths of 0-20cm using soil auger. The physico-chemical of soils was analyzed in the standardized soil laboratory procedure through the analysis of soil samples augured from three major land use systems. The results obtained from this study explore that the kebele soil did not showed the textural class difference in three land use system all showed clay loam, texture. The value of soil bulk density was increase in cropped land followed by grazing land and low in forest or reserved area land use system it ranges from 1.37, 1.24 and 1.13 g/cm 3 respectively. The percent of total porosity soils under the cultivated land was recorded average of 48.3, grazing land use also 53.2% and land use forest 57.3%. All of the soil chemical properties of the present research site were numerical influenced by land use system and soil textural class. For example, the highest value was recorded in basic cations Ca (10.02 cmol/kg), Exch-base of Mg (5.46cmol (+) /kg),Exch-base K (5.45cmol (+) /kg)and CEC (28.17 cmol (+) /kg) were observed under the forestland as compared to the lowest values (5.64, 2.05and 1.97cmol/kg), respectively, in the cultivated land. The present study showed that soil fertility status decrease as land use type goes to from forest to pasture and farming lands. Hence, it is possible to infer that continuous and intensive cultivation degrade plant essential nutrients highly which urge to take action for modifying its fertility status of the agricultural soils of in the Abol district. Keywords : -land use effect, change, physical, chemical, properties DOI: 10.7176/JRDM/75-01 Publication date: May 31 st 2021

Does coal mining benefit local communities in the long run? A sustainability perspective on regional Queensland, Australia

The Bowen Basin in Central Queensland is one of the most active coal mining regions in Australia. Coal mining is highly lucrative and a major contributor to the Australian economy. However, that industry is also responsible for many social and environmental impacts, including air and water pollution, soil erosion, destruction of biodiversity, health-related issues and reduced community cohesion in mining areas. With pressing issues like climate change requiring an energy transition and the danger posed to the Australian economy by an over-reliance on coal exports, the decision to support that industry becomes increasingly questionable. In this study, we compare coal mining, livestock grazing and nature conservation expansion scenarios in the Bowen Basin over a 31-year period. We conduct a hybrid cost-benefit analysis, combining primary data and semi-quantitative weightings constructed from a social impact risk matrix. We estimate the net public benefits of each land use option, and the externalities that they may generate. When solely considering the economic benefits of each scenario, coal mining is by far the better option, generating 10 to 14 times more benefits than grazing and 800 to 3000 times more benefits than nature conservation. However, when including the costs of negative externalities, we find that the net present value of coal mining becomes negative (-$538 to -$690 billion on average), while grazing ($2.84 to $2.85 billion) and nature conservation ($16.35 to $79.29 million) remain positive. Therefore, this study contributes to the much-needed literature that can help demonstrate the many impacts of coal mining and the long-term risks that industry may pose to local communities in regional areas of Australia. • We study coal mining expansion in the Bowen Basin, Central Queensland, Australia. • We compare coal mining, grazing and nature conservation land use scenarios. • A hybrid cost-benefit analysis is conducted, relying on a social impact risk matrix. • Social and environmental impacts of coal mining and grazing are estimated. • Coal mining becomes a less desirable option when externalities are factored in.

Fertility Status of Acid Soils under Different Land Use Types in Wolaita Zone, Southern Ethiopia

Information on soil fertility status of acid soil of a particular area as affected by land use type is important for developing sound soil management systems for improved and sustainable agricultural productivity. The main objective of this study was to assess the fertility status and effect of land use change on soil physicochemical properties. In this study, adjacent three land use types, namely, enset-coffee, crop, and grazing land use were considered in four districts (i.e., Bolos Sore, Damot Gale, Damot Sore, and Sodo Zuria) of Wolaita Zone, southern Ethiopia. Soil samples were collected from a depth of 0–20 cm from each land use type of the respective districts for physicochemical analyses. The results showed that land use types significantly affected ( P ≤ 0.05 ) soil properties such as bulk density, available P, exchangeable potassium, exchangeable acidity, exchangeable bases (Na, K, Ca, Mg), exchangeable acidity, and CEC. Besides, soil pH, OC, and TN were influenced significantly ( P ≤ 0.05 ) both by districts and land use types. The very strongly acidic soils were found predominantly in the crop and grazing lands whereas a neutral acidity level was found in the enset-coffee land use type of four districts. In conclusion, the study proves that land use type change within the same geographic setting can affect the severity of soil acidity due to over cultivation and rapid organic matter decomposition. Finally, the study recommends an in-depth study and analysis on the root causes in aggravating soil acidity under crop and grazing land use types.

Riparian erosion from cattle traffic may contribute up to 50% of the modelled streambank sediment supply in a large Great Barrier Reef river basin

Great Barrier Reef (GBR) catchment management has been constrained by knowledge gaps regarding streambank erosion processes in grazing lands. To help reduce these uncertainties a remote sensing study using high-resolution imagery estimated sediment contributions from cattle traffic on streambanks of a GBR river basin. Results suggest cattle ramps and ramp trails may contribute up to 50% of the modelled streambank sediment supply. Once a suitable delivery ratio is applied, this estimated supply may contribute up to 30% of the modelled fine sediment exported from the Fitzroy River Basin. These findings may also offer a plausible explanation for the first-flush of high sediment concentration observed early in flood hydrographs. Overall, the results could help identify what proportion of currently modelled subsoil erosion is generated by riparian cattle traffic. Future studies applying similar methods could provide useful initial estimates of streambank ramp erosion from grazing land use in other GBR river basins.

Human Ecology of Daily Grazing and Pasture Land Use by a Nomad’s Community in Western Mongolia

Human Ecology of Daily Grazing and Pasture Land Use by a Nomad’s Community in Western Mongolia

Liver fluke in Irish sheep: prevalence and associations with management practices and co-infection with rumen fluke

BackgroundThe present study aimed to identify the national prevalence of Fasciola hepatica in Irish sheep and to conduct a risk analysis assessment based on management and treatment practices in participating flocks. Also, co-infection with rumen fluke was quantified and its association with liver fluke and management practices was assessed.MethodsA total of 305 sheep flocks were selected ensuring even national representation of the sheep population. Participating farms were asked to complete a survey questionnaire on farm management practices and submit faecal samples during the winter of 2014–2015. Pooled faecal samples were analysed for the presence of F. hepatica and co-infection with rumen fluke. Apparent and true prevalence were calculated, additionally, the rate of co-infection with rumen fluke was also obtained. Correlation and regression analyses were used for assessing associations between management practices, liver fluke infection and co-infection with rumen fluke.ResultsThe national true prevalence of F. hepatica was 50.4% (n = 305). Regional prevalence varied from 41% in the east to 52% in the south. Co-infection with rumen fluke was observed in 40% of the studied population and correlated with increased F. hepatica egg counts (OR = 2.9; P ≤ 0.001). Predominant breeds were Suffolk, Texel and Horned Mountain breeds. Beef cattle were the most frequent type of other livestock present on farms and mixed species grazing was frequently reported (73%). More than half of the flocks reported a mid-to-late lambing period (March-April). Use of mountain land for grazing was of 32%. Flukicides were most commonly used twice over the autumn-winter period. Regression analyses highlighted significant association of F. hepatica status, with the presence of other livestock on farm, frequency of flukicides used during the winter and clinical presentation of liver fluke. A significant increase in eggs per gram of faeces was observed in Charollais sheep in comparison with all other breeds. Co-infection with F. hepatica and Calicophoron daubneyi was also significantly associated with the presence of other livestock on the farm, type of flukicide used and clinical fasciolosis.ConclusionsThe present study provides up-to-date information on the prevalence of F. hepatica in Irish sheep and adds insight to the epidemiology of the disease. These findings will be useful for designing new holistic control measures for F. hepatica infection.

Impacts of land use and topography on soil organic carbon in a Mediterranean landscape (north-western Tunisia)

Abstract. This study evaluates the impact of land use and topographic features (slope and aspect) on soil organic carbon (SOC) within the Wadi Beja watershed in north-western Tunisia. A soil spectral library was set up to assess the variation in the SOC for 1440 soil samples from four land use types (field crops, permanent crops, forest, and grazing land), three slope categories (flat, moderate, and steep) and two aspects (north- and south-facing). For field crops, only one factor – slope – significantly affected SOC, with SOC content in north-facing areas appearing to be higher in flat areas (0.75 %) than in hilly areas (0.51 %). However, in south-facing areas, SOC content was also higher in flat areas (0.74 %) than in hilly areas (0.50 %). For permanent crops, which were inter-planted with field crops, the slope significantly affected SOC content, which improved to 0.97 % in flat north-facing and 0.96 % in flat south-facing areas, scoring higher than hilly south- and north-facing areas (0.79 %). In the grazing land use system, both of the investigated factors – aspect and slope – significantly affected the SOC content, which was significantly higher in flat areas (north-facing: 0.84 %, south-facing: 0.77 %) than in hilly areas (north-facing: 0.61 %, south-facing: 0.56 %). For the forest, none of the factors had a significant effect on SOC content, which was higher in flat areas (north-facing: 1.15 %, south-facing: 1.14 %) than in steep areas (1.09 % in north-facing areas and 1.07 % in south-facing areas). This study highlights the ability of visible and near-infrared (VNIR) spectroscopy to quantify C in diverse soils collected over a large diverse geographic area in order to indicate that calibrations are feasible, and therefore, assessing the variation of SOC content under land use and topographic features (slope and aspect) will result in better sustainable land management planning.

Variability of soil surface characteristics in a mountainous watershed in Valle del Cauca, Colombia: Implications for runoff, erosion, and conservation

Understanding catchment sediment or solute transport frequently relies on understanding of soil nutrient conditions and physical properties. This study investigates hydropedological patterns in a tropical catchment by understanding soil nutrient and soil surface changes. Soil nutrient concentrations and hydraulic properties were measured from the La Vega micro watershed in the southwestern Colombian Andes at 16 distributed locations in four elevation ranges (between 1450 and 1700 m a.s.l.). The site is a part of a conservation partnerships which implements programs and monitor impacts. Soil samples were analyzed for total nitrogen (TN), Bray II-available phosphorus, exchangeable cations, pH, organic matter, and texture. Soil hydraulic conductivities at two depths (0–5 cm and 5–10 cm) were determined in conservation implementation areas (enclosures and natural regrowth). In the upper elevation range, regrowth of natural vegetation was found on deep soils (∼3 m) with moderate infiltration (26 cm hr−1), the lowest bulk density (0.92 g cm−3), and the highest TN (0.4%). The lowest elevation (mixed land use of grazing and riparian forests with deep profiles) had the lowest infiltration (4 cm hr−1), highest bulk density (1.02 g cm−3), and the lowest TN (0.26%). In the middle elevation ranges, conserved tropical forest vegetation were located on shallow soil depths with high organic matter (∼6%) and high infiltration (86 cm hr−1). The lowest infiltration rate average (2.3 cm hr−1) exceeded the estimated erosive regional precipitation intensity (∼2.5 cm hr−1) about 60% of the time, while the median infiltration rate (10 cm hr−1) exceeded rainfall intensities 94% of the time, indicating that infiltration excess and saturation excess runoff mechanisms are both present. Coupling data with sediment concentration and solute concentration patterns can help discern correlations between scales and will help to monitor effectiveness of conservation programs aimed at sustaining ecosystem services.

The effect of forestry management activities on stream water quality within a headwater plantation Pinus radiata forest

Many long-term forestry water quality studies focus on the impact of the harvesting phase of forestry operations. As a result, the water quality impacts of other activities such as forest (re)planting, thinning and fertilising are less well understood. Here we report the results from 23 years of monthly water quality monitoring from a steep headwater catchment within the Waikato region, New Zealand. Three experimental sub-catchments were planted in different proportions of Pinus radiata (PW2 = 100%, K-Pine 57%; PW3 = 36%). PW2 and PW3 were historical pastoral sites in the first rotation of plantation forestry and K-Pine was harvested and subsequently planted in a second rotation of forestry. All sites underwent two phases of stand thinning six and eight years after planting. The most significant effect of forestry was the increase in nitrate-N (NO3-N) and total nitrogen (TN) concentrations in response to both stand planting and stand thinning operations. Planting resulted in significant increases in NO3-N, TN and DRP over a four-year planting period at PW2. Significant increases in NO3-N and TN were detected over a four-year thinning period, at all three experimental sites. We propose that stream NO3-N and TN concentrations increased in response to stand planting at PW2 because of the change in physical conditions (e.g. increased stream shading, proliferation of nitrogen fixing weeds and decreased spatial extent of seepage wetlands) caused by the change in land use. Increasing nitrogen concentrations due to decreasing stream runoff could also be contributing a factor. Any decrease in NO3-N and TN concentrations in response to increased uptake by the rapidly growing P. radiata appears to have been masked by these other factors. However, the increase in NO3-N and TN concentrations in response to stand thinning at all three experimental sites suggests that NO3-N uptake by growing trees is an important process. Over the entire forestry period, median NO3-N concentrations at PW2 (first rotation site) increased by a factor four (400–1590 µg l−1). The median NO3-N during the post-thinning period was also one order of magnitude higher than those measured at K-Pine (second rotation site) during the post-thinning period. We attribute these differences to the NO3-N legacy within soil and/or groundwater of the previous sheep and beef cattle grazing land use. Long-term use of the PW2 catchment for forestry may eventually reduce NO3-N concentrations to the lower levels measured at K-Pine. Therefore, while NO3-N concentrations and loads may increase in response to the establishment of plantation forestry we envisage that these will decline if plantation forestry continues beyond the first rotation. This research highlights: (i) the complex nature of the response of stream water quality to catchment land use changes, and (ii) the value of studies that monitor the impact of land use/cover change over the long-term.

English

Understanding and assessing soil organic carbon stock (SOCS) within the framework of greenhouse gas emissions and land degradation is so crucial in combating climate change and enhancing ecological restoration. The goal of this study was to quantify the current SOCS in major land use types in Kersa sub watershed, eastern Ethiopia. Replicated soil samples from 0 to 20, 20 to 40, and 40 to 60 cm depth were collected from three major land uses types: grazing, cultivated, and fallow lands. Analysis of variance (ANOVA) was used to compare means and Pearson correlation analysis was used to see relationships between selected soil parameters. The results of the study revealed significant difference in soil organic carbon stock under the different land use types (P&le; 0.05). Soil under grazing land use type had significantly higher values of SOCS (42.9 t/ha and 32.9 t/ha) than cultivated land use type (32.6 t/ha and 26.3 t/ha) and fallow land use type (23 t/ha and 12.5 t/ha) in surface and sub surface layers, respectively. Similarly, SOCS decreased with soil depth in all the land use types and showed positive and significant correlation (P&le; 0.05) with clay content while negatively and significantly correlated with bulk density. The results show potential contribution of vegetation cover in land use to enhance soil organic carbon sequestration and environmental protection. Key words: Land use, organic carbon, soil organic carbon stock, carbon sequestration.

The challenge of abandonment for the sustainable management of Palaearctic natural and semi-natural grasslands

AbstractDisturbance by biomass removal is a crucial mechanism maintaining the diversity of Palaearctic grasslands, which are unique biodiversity hotspots. The century-long traditional land use of mowing, grazing and burning, has been fundamentally changed in many parts of the Palaearctic. Due to socio-economic changes, large areas of former pastures and meadows have been abandoned, leading to a succession towards secondary scrublands or forest and the encroachment of competitor grass species, all leading to a decrease in biodiversity. Here we report the causes and consequences of the cessation of traditional grassland management regimes, provide strategies for reducing the impact of abandonment and consider these from the perspective of sustainability. We consider the possibilities for initiating sustainable management regimes in the contemporary socio-economic environment, and discuss the prospects and limitation of alternative management regimes in the conservation of grassland biodiversity. These themes are also the core topics of this Special Feature, edited by the EDGG. We hope that this Special Feature will encourage steps towards more sustainable strategies for the conservation of Palaearctic grasslands and the integration of the sustainability perspective into their conservation.

Effects of European Union agricultural policies on the sustainability of grazingland use in a typical Greek rural area

Recent changes in the Common Agricultural Policy (CAP) introduced different definitions regarding the eligibility of various types of land used by grazing animals. In particular, shrublands and other low-quality areas which have traditionally been used as grazinglands are now not eligible for European Union income support payments. Subject to these changes, a large part of livestock farms will be affected, being partially or fully deprived of EU income support. In addition to these policy-driven changes, pasture-fed livestock farms in Greece are faced with a unique system of grazingland allocation, as all grazing areas in the country are state-owned. These areas are allocated for a short period either directly to farmers who are permanent residents of the Municipalities or to other livestock farmers through an auction system, which does not take into account the grazing capacity thus bringing about environmental degradation. This paper investigates the effects of CAP changes and of this communal land allocation system based on the findings of a typological analysis. The study focuses on a typical Greek territory in terms of land uses, economic activities and sociodemographic developments. Data from a questionnaire survey are used to build a typology of local livestock farms in terms of their nutritional management and land use characteristics and then the profile of each type is investigated through the estimation of a Multinomial Logit Model where the dependent variable is the cluster participation. Three distinct types of farms (clusters) are determined. Cluster 1 includes traditional farms which rear sheep and goats and bovine for meat, which are highly dependent on grazingland uses and EU income support. Cluster 2 farms – mainly sheep and goat – have evolved a ‘double’ dependency on land in the form of grazingland but also of cropland for feedstuff production, which renders them more resilient to policy changes. Finally, Cluster 3 farms are intensive dairy cattle farms and use artificial (cultivated) privately-owned grazinglands and cropland for feedstuff production. Market-oriented measures are proposed for each type and suggestions for an integrated land use plan are made, including long-term leasing of land and the consideration of environmental criteria for land allocation, thus rendering farmers responsible for keeping their land in a good production state.

Soil property variations in relation to exclosure and open grazing land use types in the Central Rift Valley area of Ethiopia

Land degradation and unsustainable management practices have resulted in soil organic carbon and nutrient depletion, hydrological instability, reduced primary productivity, and low biological diversity. In response to these problems, communities in the Central Rift Valley area of Ethiopia have started to establish exclosures about three decades ago. This study has investigated the variations in selected soil properties (soil textural fractions, bulk density, soil moisture content, pH (H2O) and soil organic carbon content) under two land use types: open grazing land and exclosures in the Central Rift Valley of Ethiopia. Results showed that soil organic carbon varied significantly with land use types (p = 0.040), soil depths (p = 0.010) and the interaction effect (p = 0.039). The soil moisture content showed significant variation (p < 0.0001) only with soil depth. Exclosure land use type has shown an improvement in soil organic carbon against the findings by Mekuria et al. [International Conference on Advances in Agricultural, Biological & Environmental Sciences (AABES-2014), Dubai (UAE) 2014]. Thus, highly degraded open grazing should be designated as exclosure land management zone to restore and rehabilitate severely degraded landscape in the fragile environment of the rift valley area of Ethiopia.

A multi-criteria inference approach for anti-desertification management

We propose an approach for classifying land zones into categories indicating their resilience against desertification. Environmental management support is provided by a multi-criteria inference method that derives a set of value functions compatible with the given classification examples, and applies them to define, for the rest of the zones, their possible classes. In addition, a representative value function is inferred to explain the relative importance of the criteria to the stakeholders. We use the approach for classifying 28 administrative regions of the Khorasan Razavi province in Iran into three equilibrium classes: collapsed, transition, and sustainable zones. The model is parameterized with enhanced vegetation index measurements from 2005 to 2012, and 7 other natural and anthropogenic indicators for the status of the region in 2012. Results indicate that grazing density and land use changes are the main anthropogenic factors affecting desertification in Khorasan Razavi. The inference procedure suggests that the classification model is underdetermined in terms of attributes, but the approach itself is promising for supporting the management of anti-desertification efforts.

Fuelwood collection and its impacts on a protected tropical mountain forest in Uganda

Local communities who live close to protected tropical forests often depend on them for woodfuel, their main source of energy. The impacts of fuelwood extraction in humid forests are rarely studied, yet the extraction of wood for fuel can impact forest structure, function and biodiversity. We assessed the effects of fuelwood collection on the forest of Mt Elgon National Park (Uganda). We interviewed 192 households about fuelwood use and surveyed dead wood in 81 plots inside the park. Forest was the most important source of fuelwood. People collected on average between 1.1 and 2.0m3 of fuelwood per capita per year. Other activities involving wood fuel extraction from the forest included illegal commercial fuelwood harvesting and charcoal making. Quantities of dead wood were affected by fuelwood collection up to at least 1000m inside the boundary of the park. Depletion of dead wood inside the park was greater in the sites where the population was most dense. Nevertheless, people who planted more trees on their own land perceived land outside the park to be important and valued old growth forest less as a source of fuelwood. Highly-preferred tree species were most depleted, particularly when they were also valued timber trees, such as Prunus africana, Popocarpus milianjianus, Allophylus abyssinicus and Olea spp. Locally dominant species were less affected. Impacts varied among sites depending on the history of agricultural encroachment and locally-specific forest uses, e.g. harvesting of trees for poles or use of the forest land for grazing. Allowing the collection of dead wood in forests is double-edged as it creates opportunities for other activities that are more damaging. Demand for wood fuel from tropical forests is still likely to grow in the foreseeable future. Our results indicate that the forest may become more degraded as a result, with negative consequences for the people who depend on the forest and for conservation. Research into local ecological and cultural contexts and perceptions concerning costs and benefits can help devise more sustainable management options, including alternative sources of fuel.

Carbon sequestration in soils-A Review

Agricultural soils can be a source or sink for atmospheric CO2 depending upon the management practices and land use patterns. Progressive increase in the concentration of GHGs since industrial era has created worldwide interest in identifying strategies to reduce concentration of these gases in the atmosphere. Carbon sequestration is an important technology for the maintenance of optimum CO2 level in the atmosphere, which in-turn results in reducing the recent increase in atmosphericcarbon dioxide, contributing to global warming. Carbon stored in soilsis 2–4 times more as compared to that stored in the atmosphere and around 4 times that C stored in vegetation. The potential carbon sequestration in world soil is 0.4–1.2 Gt C/year. Therefore, it is understandable that the soil C sink has significant impact on sequestering CO2. The objective of the paperis to review the potential of soils in sequesteringcarbon and mitigating the accelerated green house effects by changing agricultural management practices viz.conservation agriculture, organic agriculture, grasses/forages, proper grazing management, biochar and land use management. Significant amount of soil organic carbon (SOC) could be sequestered by changing conventional tillage to conservation tillage, its effect is noticeable only in long term rather than short term tillage practice. Legume-based crop rotation is more efficient in converting biomass C into soil organic C than the grass based. Rotational grazing improves grass quality and reduces the total amount of CO2 released into the atmosphere. Another approach in sequestrating atmospheric carbon is biochar production and mixing it into soil.

Optimising carbon sequestration in arid and semiarid rangelands

Destocking degraded rangeland can potentially help climate change mitigation by re-sequestering emitted carbon. Broad-scale implementation has been limited by uncertainties in the magnitude, duration and location of sequestration and the profitability relative to the existing grazing land use. This paper employs a novel methodology to assess potential rangeland sequestration and its profitability, using 31Mha of rangeland in New South Wales, Australia as a case-study. This approach combines remotely sensed data and modelled estimates of various components. Remotely sensed, synthetic aperture radar data were used to determine woody biomass of minimally degraded forest (benchmarks) and neighbouring more-degraded forest, followed by sequestration modelling using non-linear growth rates based on woody thickening and slow-growing plantations, scaled to the benchmarks. Livestock concentration and livestock-based farm profits were modelled. We compared sequestration and grazing net profits, for a carbon price of AUD$10Mg−1 CO2-e, at different growth stages for different levels of forest attrition. We found that broad-scale destocking with subsequent C re-sequestration was initially unprofitable compared with grazing. However, after 50 years, with full costing of C emissions, the returns were similar for the two alternatives of continued grazing or re-sequestration, for areas with biomass below benchmark levels. Reforestation of recently deforested land represents the most profitable option with profitability increasing with growth rate. Emissions of soil organic carbon, set in motion by climate change over the next century, were calculated to be the largest of all sources. Emissions from biomass, induced by climate change, will be higher where vegetation cannot adapt. The secondary effects of climate change will reduce re-sequestration and grazing profits, possibly limiting the carbon stored by re-sequestration projects.