Land‐use and cover changes (1988–2002) around budongo forest reserve,NW Uganda: implications for forest and woodland sustainability

Land‐use and cover changes around Budongo Forest Reserve (BFR) were analysed from multi‐temporal LandSat images (1988 and 2002) and associated field‐based studies in 2003–2004. Three major land‐use and cover classes: forest/woodland, sugarcane plantations and grassland/shifting‐cultivation/settlements were clearly discriminated. The area under sugarcane cultivation increased over 17‐fold, from 690 ha in 1988 to 12729 ha in 2002, with a concomitant loss of about 4680 ha (8·2 per cent) of forest/woodland, mainly on the southern boundary of BFR. Land‐use and cover changes were a result of (a) agricultural expansion, (b) increasing human population, exacerbated by large influxes of refugees, (c) conflicts of interest and political interference in the management of BFR and (d) unclear land tenure. Agriculture is the main land‐use practice and source of income to local people, with commercial sugarcane and tobacco as the primary cash crops. Individual smallholder sugarcane plantations covered distances ranging from 30 to 1440 m along the BFR edge, with no buffer zone, resulting in direct conflicts between farmers and forest wild animals. There is an ever‐increasing need for more land for agricultural expansion, resulting in continued loss of forest/woodland on private/communal lands and encroachment into BFR. This unsustainable agricultural expansion and the local people's perception of BFR as an obstacle to agriculture, threatens the conservation of its threatened wild plants (e.g. Raphia farinifera) and the endangered chimpanzees. Therefore, their sustainable management for both development and conservation will require strong and incorruptible institutions that will seek a balance between resource exploitation and conservation. Copyright © 2008 John Wiley & Sons, Ltd.     

Continuing land degradation: Cause–effect in Ethiopia's Central Rift Valley

The Central Rift Valley (CRV) is one of the most environmentally vulnerable areas of Ethiopia. Most of the lowland in the CRV is arid or semiarid, and droughts occur frequently. We studied the dynamics of land use and cover and land degradation by analyzing Landsat data from 1973, 1985, and 2006 using Geographic Information Systems and remote sensing techniques. The analysis revealed that in the last 30 years, water bodies, forest, and woodland decreased by 15·3, 66·3, and 69·2 per cent, respectively; intensive cultivation, mixed cultivation/woodland, and degraded land increased by 34·5, 79·7, and 200·7 per cent. The major causes of land use and cover change (LUCC) and land degradation in the area were population and livestock growth in regions of limited resources, unsustainable farming techniques, the Ethiopian land tenure system and poverty. Lake level and area decline, and accelerated land degradation are the major environmental impacts of LUCC observed in the CRV. The environmental and socio‐economic consequences of LUCC and land degradation are far‐reaching. As a result of the expansion of land degradation over time, agricultural productivity has decreased and worsened food insecurity (shortages) and poverty in the Ethiopian CRV. In addition, if current trends in LUCC continue, Lake Abiyata will dry up by 2021. A detailed study of the degradation amount in relation to soil erosion, sediment yield to the lakes and catchment characteristics should be made using adaptable models; so as to guide the implementation of comprehensive and sustainable land use management by giving more attention to erosion prone areas. Copyright © 2010 John Wiley & Sons, Ltd.     

Perceptions of land‐degradation,forest restoration and fire management: A case study from Malawi

Understanding local perceptions of degradation and attitudes to fire management are critical for gaining support for restoration work and improving livelihoods. Deforestation and annual burning are causing significant land degradation problems in the area around Bandawe, northern Malawi. We mapped evidence of soil erosion and remaining areas of woodland. Gully erosion was common and primarily associated with heavily utilised footpaths. Areas between gullies showed signs of significant soil movement. Remnant patches of native woodland existed but were small, degraded and isolated. We interviewed local households to understand local awareness and impacts of land‐degradation, its perceived cause and preferred methods for restoration. All households were aware of the presence of gullies and reported associated problems of flood damage. Most households believed erosion was a result of deforestation. Burning practices were seen to have exacerbated erosion problems. Changing fire management practice was not seen as realistic as it risked reducing the productivity of grasses and fires were perceived to be too difficult to control. Tree planting was the community's preferred approach to tackling erosion. Their focus was on planting exotic fruit and timber trees around houses and they often requested that such work be done by volunteers. Such attitudes may have been influenced by recent extension work and a desire to secure ownership of utilisable resource. Ecologists in the miombo zone should focus on improving fire management practices and involving communities in creating diverse secondary woodlands that provide a range of goods and services. Copyright © 2010 John Wiley & Sons, Ltd.     

The impact of cultivation on carbon fluxes in woody savannas of Southern Africa

The rapid transition from miombo woodland and savanna to maize-based agriculture in Southern Africa results in a near universal loss of total system and biomass carbon. Forests and savannas occupy approximately 3.1 million km² in southern Africa. Two natural ecosystems, a miombo woodland (Zimbabwe) and a broadleafed dry savanna (South Africa), contained 48 and 94 Mg C ha^?1, respectively. Clearing of the miombo and establishment of maize-based agriculture on a sandy Alfisol resulted in a decline in total soil organic carbon from 28 to as little as 9 Mg ha^?1. This decline is not related to the annual aboveground productivities which, in many cases is greater in the cropping system than in the savanna or forest. Severe declines in total soil organic matter resulting from shifting cultivation were also observed in coastal Mozambique. The CENTURY plant/soil simulation model was used to simulate long-term carbon dynamics a miombo woodland and maize-based cropping system in Marondera, Zimbabwe. The miombo woodland continues to accumulate total system C but shifting cultivation and commercial cultivation of maize result in annual carbon losses of 0.15 and 0.14 Mg ha^?1 yr^?1. Increases in temperature (2° C) accompanied by 25% increases in photosynthetic efficiency did not effect the decline in total system carbon, however, improved organic matter management within the agroecosystem reduced the losses in total system carbon within the agroecosystem by 57% under the climate change scenario.     

Assessment of deforestation impact on soil erosion in loess formation using 137Cs method (case study: Golestan Province,Iran)

Golestan, a province in the North-East of Iran, is characterized by high coverage of loess deposits. Since 1963, the area has experienced approximately 200,000 ha deforestation due to land-use changes in agriculture and increasing demand for wood. Approximately, 110,000 ha of the clear-cut lands are under dry-farming, mainly for wheat cropping, and about 86,000 ha have been reforested. This IAEA funded project is the first attempt to use nuclear techniques in the East of Hircanian Forest for determination of on-site impacts of deforestation due to two land-use changes (i.e. dry farming and reforestation). Practicing long-term dry-farming led to 60% soil losses with a mean rate of 2 mm per year. The net erosion rate of croplands on loess deposits in the study area was 32.27 t ha⁻¹ yr⁻¹. Reforestation, cultivation of even-aged Cypress trees since 1993, showed 13 to 60 percent effectiveness in soil conservation. Dry-farming land use resulted in the loss of 95 t ha⁻¹ soil organic carbon (SOC) stock at a mean rate of 1.7 t ha⁻¹ over 54 years. Cultivating Cypress trees successfully restored the SOC content by 100% compared with the SOC in original forests. The conversion of dry-farming lands to orchards of olive trees since 2004, brought more income for farmers but were less effective in soil conservation because of low canopy cover of olive trees. Our data provide key information and guidance for land users and decision-makers about implementing strategic and sustainable conservation practices to restore degraded land.     

Land use,deforestation and reforestation in the Zambian Copperbelt

Temporal and spatial changes in land use, vegetation cover, deforestation and reforestation in the Zambian Copperbelt were studied using a combination of aerial photograph analysis, literature review and inquiries among relevant government institutions. The study showed that between 1937 and 1984 loss of natural woodlands in the Copperbelt of Zambia (total area of Copperbelt: 9,615 km²) amounted to 41 per cent woodland area (8,419 km²). The major causes of this deforestation are woodfuel collection (for firewood and charcoal), cultivation and replacement of natural woodland with forest plantations. These accounted for 38 per cent, 37 per cent and 15 per cent of the total deforestation, respectively. Before 1962 the copper mining industry used large quantities of firewood to generate electricity and this resulted in the loss of 150,413 ha of woodland between 1937 and 1961. When the mining industry switched to hydroelectricity, urban households became the major users of woodfuel. The urban population in the Copperbelt increased from 0.412 million in 1960 to 1.400 million in 1984 and its consumption of woodfuel led to the deforestation of at least 89,436 ha between 1962 and 1984. Deforested areas are left to regenerate naturally. However, due to poor management about 34 per cent of the area deforested before 1962 has failed to regenerate. Although 50,200 ha have been reforested with exotic trees, only 5,020 ha of this is on land previously deforested. Thus only about 10 per cent of reforestation efforts have contributed to the rehabilitation of damaged land. Ninety per cent of the reforestation has actually replaced standing indigenous woodland. Uncontrolled bushfires have destroyed forest plantations and have also caused the failure of woodland regeneration in deforested areas. These observations indicate that if forest resources in the Copperbelt of Zambia are to be properly managed it will be necessary:

• 1 to effectively regulate land use changes and;
• 2 to control bushfires.

     

Spatial structures of soil organic carbon in tropical forests—A case study of Southeastern Tanzania

Southeastern Tanzania serves as a typical example of soil degradation and soil organic carbon (SOC) losses on the African continent. Although sequestration of SOC through aforestation or reforestation proved favorable, these measures are restricted by the ability to produce rapid, cost-effective and precise sampling schemes. The aim of this study is to contribute to a better knowledge of the spatial distribution of soil C in tropical natural and plantation forest. This paper presents sampling strategies for estimating mean SOC values as well as for SOC mapping, based on different methods for SOC determination and on different precision levels. To do so we conducted a carbon variability study in five common forest types of Southeastern Tanzania (coastal dry forest, Miombo woodland, teak plantation, pine plantation and cashew plantation) using conventional statistical methods, as well as geostatistics. In the 5 forest types of this study, SOC stocks in the upper 5 cm ranges between 5 (in the cashew plantation) and 13 (in the coastal forest) t ha^− 1. The optimal sampling distance for measuring mean SOC stocks varies between 36 m (in the patchy miombo woodland) and 422 m (in the homogenized cashew plantation). Sample sizes fluctuate between 6 and 72 (1 t ha^− 1 precision) for respectively cashew plantation and coastal forest. A rectangular grid with a sample interval of 25 m can be used for SOC mapping with a point kriging estimation error of 3.0 t ha^− 1 in the coastal forest, 2.6 t ha^− 1 in miombo woodland, 2.2 t ha^− 1 in the teak plantation and 1.1 t ha^− 1 in the cashew plantation. Since the pine plantation has no spatial structure; samples can be arranged randomly and its best soil map has an average C content attributed over the whole field. Refining the sampling strategy with a new spatial variability study in other forest types can be based on a regular grid with sampling distances of half the range identified in this study. This paper proves that the optimal sampling scheme varies strongly as a result of the different spatial behavior of SOC in forests and depends on the required precision and research question. Only when the right strategy is followed, high standards of precision can be met without economic loss or risk of statistical misinterpretation.     

Is rural migration a threat to environmental sustainability in Southern Burkina Faso?

There is growing evidence that population pressure on the land has become the most intractable problem in the developing countries where demand for food exceeds the food production capacity of the land. Southern Burkina Faso has experienced rapid population growth, mostly driven by immigration of farmers. This study was carried out in Sissili Province and used satellite images acquired over 31‐year period, census and survey data to capture migration patterns and its impacts on land use change. Results showed that migrant population which accounted for only 3 per cent in the study area in 1976 shifted to 57 per cent in 2007. Migrant people were using improved technology to progressively convert forest land to cropland. Cropland increased at an annualized rate of 0·46 per cent to the detriment of the dense forest and woodland which decreased at 0·57 per cent per annum. Population growth was highly correlated with increasing area of cropland (r² = 0·95, p = 0·014) and declining dense forest (r² = 0·78) and woodland (r² = 0·95) covers. It can be concluded that rural migration, driven by the relatively good soil and rainfall conditions in the recipient area, is accounted for deforestation in the study area. If rural migration is not checked, it will seriously degrade the environment. Copyright © 2009 John Wiley & Sons, Ltd.     

Temporal and spatial changes of soil erosion under land use and land cover change based on Chinese soil loss equation in the typical watershed on the Loess Plateau

Land use and land cover change (LULCC) directly affect the temporal and spatial change of soil erosion. As a typical governance watershed in the hilly and gully area of the Loess Plateau, the Jiuyuangou watershed has experienced significant LULCC in the past 10 years due to conversion of farmland to forests, economic construction, and cropland abandonment. However, the evolution process of soil erosion change and LULCC in the watershed is unclear, as is the relationship between the two. This study used satellite images to extract information on LULCC in the watershed and the Chinese soil loss equation (CSLE) model to evaluate the temporal and spatial evolution of soil erosion in the watershed from 2010 to 2020. The main results showed that (1) the continuous vegetation restoration project in the watershed reduced soil erosion from 2010 to 2015; however, the increased frequency of extreme rainfall events after 2015 reduced its impact. The annual average soil erosion modulus decreased from 10.85 t ha⁻¹ year⁻¹ in 2010 to 8.03 t ha⁻¹ year⁻¹ in 2015 but then increased to 10.57 t ha⁻¹ year⁻¹ in 2020; (2) the main land use and land cover (LULC) type in the Jiuyuangou watershed is grassland, accounting for 62% of the total area, followed by forestland, cropland, buildings, and water. Cropland has the largest multi-year average soil erosion modulus, followed by grassland and buildings, with forestland having the smallest; (3) significant spatial correlations occurred between soil erosion change and LULCC for common ‘no change’ and common ‘gain’ in the settlements, roads, and areas near the human influences with good soil and water conservation, but not other regions due to the influence of climatic factors (heavy rain events). Thus, we should repair terraces, control dams in the watershed, and actively conserve water and soil. This study provides a scientific reference for planning and managing water and soil conservation and ecological environment construction in the watershed.     

Effect of land use on soil nutrients in the loess hilly area of the Loess Plateau,China

Understanding the effects of land use change on soil properties is important for soil quality improvement and sustainable land use. In this study, six land use types including wasteland (WLD), cropland (CLD), abandoned land (ABD), artificial grassland (AGD), shrubland (SLD) and woodland (WOD) were selected to analyse the effects of land use types on soil nutrient in the Anjiapo catchment in the western part of the Loess Plateau in China. Significant differences were found in soil organic matter (SOM), total nitrogen (TN) and nitrate nitrogen (NON) (P < 0.01) between the six land use types. Our study also showed that land use types have different effects on soil nutrient storage, and vegetation restoration may improve soil nutrients and soil quality. While crop plantation can significantly decrease soil fertility, the trend can be reversed by cropland abandonment and afforestation. It is recommended that more C input, alternative cultivation practices, vegetation restoration and education and techniques training of local farmers could be used to improve soil conditions and to advance the sustainable land use and local development in the loess hilly area in the Loess Plateau of China. Copyright © 2005 John Wiley & Sons, Ltd.     

The responses of soil,litter and root carbon stocks to the conversion of forest regrowth to crop and tree production systems used by smallholder farmers in eastern Amazonia

The impact of substituting forests for smallholder agricultural production systems on soil carbon (C) stocks is not well understood in Brazilian Amazonia. Most surveys of soil C stocks are restricted to the top 30 cm of soil and do not include measurements of litter and root stocks. Here, we quantify the stocks of C in soil (0–100 cm depth), aboveground litter and coarse roots of traditional (slash‐and‐burn) and alternative (Schizolobium amazonicum‐planted forest and silvopastoral system) smallholder agricultural systems, which were compared with a reference area (forest regrowth) in the eastern Amazonia. The soil C stocks in the 0–100 cm layer were larger in the forest regrowth treatment (156.8 ± 15.5 Mg/ha) than in the other treatments (S. amazonicum = 85.3 ± 6.5, silvopastoral = 108.0 ± 4.4 Mg/ha) but did not differ from the soil C stock in the slash‐and‐burn treatment (127.2 ± 6.1 Mg/ha). The soil C stocks at the 0–30 cm layer, which represented 33–50% of the total C of the 0–100 cm layer, did not differ among the treatments. The litter C stocks were ranked in the following order: silvopastoral > forest regrowth > S. amazonicum > slash‐and‐burn. The forest regrowth treatment had a greater coarse root C stock (0.84 ± 0.10 Mg/ha) than the other treatments (silvopastoral = 0.28 ± 0.03, S. amazonicum = 0.18 ± 0.03, slash‐and‐burn = 0.27 ± 0.04 Mg/ha). Soil, litter and root C stocks were negatively impacted by the conversion of forest regrowth to cultivation systems.     

Analysing Spatial and Statistical Dependencies of Deforestation Affected by Residential Growth: Gorganrood Basin,Northeast Iran

This study aimed to examine deforestation and residential growth trends and their spatial dependencies from 1972 to 2010 in Northeast of Iran. First, change rates of forests and residential areas were mapped using Landsat satellite images in 1972–1987, 1987–2000 and 2000–2010. Then, the forest change patterns were interpreted using univariate local Moran's I (local univariate spatial autocorrelation), and the spatial autocorrelation between deforestation and residential growth was tested through bivariate local Moran's I (bivariate local spatial autocorrelation). Furthermore, the spatial relationships between deforestation and residential growth rates were quantified by ordinary least squares, spatial lag (SL) and geographically weighted regression. Results indicated that approximately 25% of forests have been converted to other land‐use types in the span of 38 years, since 1972. Local univariate spatial autocorrelation maps showed that significant values of high–high cluster scattered in all locations in the first span, in the east and south aspects in the second duration, and in the eastern part in the third span. Bivariate local spatial autocorrelation indicated a meaningful Moran's I values of −0·12, −0·26 and −0·20 between deforestation and residential growth, chronologically. Analyses of spatial regression models showed that geographically weighted regression performed better than SL and ordinary least squares in the first (R ² = 0·315, AIC = 6,160) and third periods (R ² = 0·27, AIC = 6,351), whereas, the validity of SL was the highest in the second period (R ² = 0·36, AIC = 6,288). However, the overall trends of deforestation and residential growth have decreased, but the rate of deforestation induced by residential growth is still significant. Spatial exploration of residential growth in deforestation leads to determine its influences in local scale for better conservation of these valuable natural resources. Copyright © 2017 John Wiley & Sons, Ltd.     

Development policies and tropical deforestation in the southern Yucatán peninsula: centralized and decentralized approaches

It is well established that for multiple biophysical contexts there are legacies of past government policies in present land conditions. Despite this recognition, however, investigation of ongoing tropical deforestation dynamics often de‐emphasizes the past. The case of the southern Yucatán peninsula demonstrates the need for historical analysis in identifying key drivers of deforestation. The most important land‐use changes in the region over the past 100 years are connected to shifts in national development policies. These shifts represent tensions between centralized and decentralized approaches to land management—as represented by the policies of Presidents Díaz (1876–1910) and Cárdenas (1934–40)—that persisted throughout the 20th century. The legacies of these reoccurring development strategies include depleted hardwood reserves, large areas of permanently cleared forest, a complicated system of land allocation, and long‐standing tensions between economic, social welfare, and environmental conservation goals. These findings suggest that while centralized and decentralized approaches to development both focus on natural resource exploitation, the rates of deforestation tend to be faster, the patterns of forest clearing more pronounced, and land‐use decision making less democratic under systems of centralized control. These conclusions hold implications for land‐use decision making today. Copyright © 2003 John Wiley & Sons, Ltd.     

Human modification of stream valleys in the western plateau of São Paulo,Brazil: implications for environmental narratives and management

Deforestation, agricultural land uses and urbanization have altered stream channels and floodplains in many regions of the world, yet occurrences of post‐settlement alluvium (PSA) and benchmark pre‐settlement horizons (Palaeosols) are unreported in many tropical and subtropical developing countries. Twentieth century land uses, motivated strongly by state subsidies in the cases of coffee and cotton cultivation and soy – wheat double cropping, caused soil erosion and the corresponding formation of PSA and stream‐channel changes in small catchments of the Western Plateau of São Paulo State, Brazil. Analysis of land‐use changes suggests necessary alteration of regional environmental management for restoration planning, water quality monitoring and control of gully erosion. Narratives of regional environmental change should address the impacts of agropastoral land uses on soil and water resources, rather than concentrating on deforestation and forest land cover. Copyright © 2000 John Wiley & Sons, Ltd.     

Global food security,biodiversity conservation and the future of agricultural intensification

There is vigorous debate about the potential for reforestation to offset losses in biodiversity associated with tropical deforestation, but a scarcity of good data. We quantified developmental trajectories following active restoration (replanting) of deforested pasture land to tropical Australian rainforest, using 20 different bird community indicators within chronosequences of multiple sites. Bird species composition in restored sites (1–24 years old) was intermediate between that of reference sites in pasture and primary rainforest. Total species richness was much less sensitive to land cover change than composition indicators, because of contrasting species-specific response patterns. For example, open-country (grassland/wetland) bird species declined in richness and abundance with increasing site age, while rainforest-dependent species increased. Results from two different landscapes (uplands and lowlands) were remarkably consistent, despite differing bird assemblages. After 10 years, restored sites averaged about half the number of rainforest-dependent bird species typical of rainforest. Mean values at around 20 years overlapped with the “poorest” rainforest reference sites, but projections suggest that >150 years are required to reach mean rainforest levels, and high variability among sites means that many were not on track towards ever achieving a rainforest-like bird community. Regional rainforest endemics were half as likely to occupy older revegetated sites as non-endemic rainforest-dependent species. Between-site variability and slow colonisation by regional endemics strongly constrain the potential of rainforest restoration to offset the biodiversity impacts of tropical deforestation. The results also mean that ongoing monitoring of biodiversity is an essential part of restoration management.     

滇西北纵向岭谷区水土保持对策研究——以怒江州为例

怒江州地处滇西北纵向岭谷区,地质地貌、降水、土壤等自然因素有利于水土流失。受"通道-阻隔"作用的影响,人类及其经济活动沿河展布或分布于山间盆地,陡坡垦殖、砍伐森林以及毁林、毁草开荒等不合理的土地利用,加剧了河谷区和两岸山间盆地的水土流失。水土保持对改善怒江州的生态环境、保障粮食和能源安全以及应对气候变化具有重要的意义,但也面临全球气候变暖、生态环境脆弱、贫困人口集中、农业生态环境退化等严峻挑战。怒江州的水土保持对策是:大力发展林业及相关产业;结合林草植被恢复,加快畜牧业发展;采取多种措施,提高耕地粮食单产。     

Impacts of land use/cover change on soil properties in the Mediterranean region of northwestern Jordan

This study was carried out to evaluate the effects of deforestation on physical and chemical properties of soils under native forest in the Mediterranean region of northwestern Jordan. Land use/cover maps of 1953, 1978 and 2002 were interpreted and analysed within GIS to quantify the shift from forest to rainfed cultivation. Six sites were sampled in a non‐changed forest and in cultivated fields, three for each. Different soil properties of texture, bulk density, organic matter, total nitrogen, pH, cation exchange capacity (CEC), phosphorous and potassium were analysed. Results showed that many forests were changed into cultivated lands at a rate more than the reforestation. Subsequently, adverse effects on the studied physical and chemical properties were observed. The most affected properties were particle size distribution, bulk density of surface soil and subsoil. Organic matter and CEC decreased in cultivated soil as compared to the forest soil. Cultivated soils were found to exhibit a significantly lower status in physical and chemical soil properties as compared to forest soils. This general decline in the soil physical and chemical properties, in turn, contributed to soil erosion, reduction of soil fertility and land degradation. There is an urgent need to improve soil quality by developing sustainable land use practices to reduce the rate of soil degradation and to ensure long‐term sustainability of the farming system in the study area and in similar biophysical settings. Copyright © 2008 John Wiley & Sons, Ltd.     

Fingerprinting Sediment Sources After an Extreme Rainstorm Event in a Small Catchment on the Loess Plateau,PR China

Soil erosion is a severe problem on China's Loess Plateau due to its fine‐grained soils and the increasing frequency of extreme rainfall events. Accordingly, this study used a 100‐year frequency rainstorm dataset to analyse sediment deposition and sources in a 27‐km² catchment with a dam field area of 0·14 km² based on the hypothesis that sediments were intercepted by the dam (before collapse) during the rainstorm event and deposited in the dam field. This study applied composite fingerprinting, which revealed the sediment source contributions and estimated sediment deposition. Sediment deposition (626·4 kg m⁻²) decreased linearly or exponentially with increasing distance from the dam. Composite fingerprints based on the optimal parameters revealed relative sediment contributions of 44·1% ± 25·5%, 37·7% ± 35·0%, 9·0% ± 11·4% and 9·2% ± 11·5% by bare ground, croplands, grassland and forests, respectively. The 5‐year cumulative sediment deposition from normal rainfall was 2·3 × 10⁴ t less than the extreme rainstorm. Bare grounds and croplands were the dominant sediment sources following both the extreme rainstorm and normal erosive rainfall events but varied at different areas of the check‐dam. Erosion patterns and start times depended on land use type, thereby affecting sediment profiles in the dam field. Furthermore, severe erosion from bare ground that were all gully slopes and gully walls occurred throughout the rainfall, whereas grasslands and forest erosion occurred earlier and croplands later. Finally, extreme rainfall promoted mass wasting on slopes, gully slopes and gully walls, which are important in determining extreme rainstorm erosion pattern variation. This study aimed to reveal erosion pattern variation under extreme rainstorm events. Copyright © 2017 John Wiley & Sons, Ltd.     

Influence of landuse on soil erosion risk in the Cuyaguateje watershed (Cuba)

Landuse changes may dramatically enhance erosion risk. Besides deforestation, also arable landuse may have an important influence on soil loss. We investigated the erosion risk in a 151 km² subwatershed of the Cuyaguateje watershed (Cuba) using the RUSLE model. It was found that the valleys used for agriculture have the highest erosion risk, with actual erosion surpassing soil loss tolerance. Over the period 1985–2000, about 14 km² of forest has been converted into arable land. As a result, the area with a very high erosion risk increased with 12%. On arable land it was found that the crop management factor C of a “tobacco/maize” rotation was 0.478, compared to 0.245 for a rotation of various crops (sweet potato, beans, maize, cassava and fallow). When maize in the “tobacco/maize” rotation was intercropped with a leguminous crop (hyacinth bean) the C factor decreased to a value of 0.369. Also contouring may halve soil loss on moderate slopes (< 10%) when high ridges are applied, which is in Cuba generally the case for maize, cassava and sweet potato.     

Soil carbon and related soil properties along a soil type and land‐use intensity gradient,New South Wales,Australia

The aim of this study was to systematically quantify differences in soil carbon and key related soil properties along a replicated land‐use intensity gradient on three soil landscapes in northwest New South Wales, Australia. Our results demonstrate consistent land‐use effects across all soil types where C, N and C:N ratio were in the order woodland > unimproved pasture = improved pasture > cultivation while bulk density broadly showed the reverse pattern. These land‐use effects were largely restricted to the near surface soil layers. Improved pasture was associated with a significant soil acidification, indicating that strategies to increase soil carbon through pasture improvement in these environments might also have associated soil degradation issues. Total soil carbon stocks were significantly larger in woodland soils, across all soil types, compared with the other land‐uses studied. Non‐wooded systems, however, had statistically similar carbon stocks and this pattern persisted whether or not carbon quantity was corrected for equivalent mass. Our results suggest that conversion from cultivation to pasture in this environment would yield between 0.06 and 0.15 t C/ha/yr which is at the lower end of predicted ranges in Australia and well below values measured in other cooler, wetter environments. We estimate that a 10% conversion rate (cultivation to pasture) across NSW would yield around 0.36 Mt CO₂‐e/yr which would contribute little to emission reductions in NSW. We conclude that carbon accumulation in agricultural soils in this environment might be more modest than current predictions suggest and that systematically collected, regionally specific data are required for the vegetation communities and full range of land‐uses before accurate and reliable predictions of soil carbon change can be made across these extensive landscapes.