In many parts of Africa, soil erosion is an important problem, which is evident from high sediment yields in tropical montane streams. Previous studies in Kenya pointed to a large contribution from catchments cultivated by smallholder farmers. This led to the hypothesis that unpaved tracks and gullies are the main sediment sources in smallholder agriculture catchments of the highlands of Kenya. The aim of this study was to investigate the sediment sources with sediment fingerprinting to generate the knowledge base to improve land management and to reduce sediment yields. Four main sediment sources (agricultural land, unpaved tracks, gullies and channel banks) and suspended sediments were analysed for biogeochemical elements as potential tracers. To apportion the catchments target sediment to different sources, we applied the MixSIAR un-mixing modelling under a Bayesian framework. Surprisingly, the fingerprinting analysis showed that agricultural land accounted for 75% (95% confidence interval 63–86%) of the total sediment. Channel banks contributed 21% (8–32%), while the smallest contributions to sediment were generated by the unpaved tracks and gullies with 3% (0–12%) and 1% (0–4%), respectively. Erosion management strategies should target agricultural lands with an emphasis on disconnecting unpaved tracks form hillslope source areas to reduce sediment yields to Lake Victoria.
Tag: agricultural land
Agricultural intensification is causing rapid habitat change in the Tonle Sap Floodplain, Cambodia
The Tonle Sap Lake and Floodplain (TSLF) supports many globally threatened species and its fishery has sustained Cambodia’s people for millennia. The rate of habitat loss has accelerated in recent years due to political and economic conditions, and a warming climate and El Niño events that created opportunities for people to burn scrubland at an elevated rate. Here, we use a point-based landcover assessment method to document the impacts of local-scale drivers, in particular agricultural intensification, on habitat trends between 1993 and 2018. The areal extent of scrubland and grassland in the TSLF declined from ~ 74% in 1993 to ~ 52% in 2018, as a result of intensification and expansion of rice cultivation. During that time period, grassland cover declined from ~ 3160 to ~ 519 km2, whilst between 2008 and 2018, scrubland cover declined from ~ 8660 to ~ 6776 km2. Habitat loss has had catastrophic implications for grassland-dependant species, such as Bengal Florican, and, we estimate that habitat changes in the TSLF may have caused carbon stocks to decline by 12% while fish productivity is also likely to have dropped, with significant implications for food security. To put this habitat loss in context, losses over the past 10 years have been nearly twice as large as published predictions of the amount likely to be lost between 2010 and 2040 due to hydropower. We suggest that the expansion and intensification of rice cultivation is the greatest current threat to habitats in the TSLF and deserves greater attention from policy makers and practitioners.
Nature-Based Solution for Balancing the Food, Energy, and Environment Trilemma: Lessons from Indonesia
Demand for food and energy is constantly increasing in line with the global population and there are widespread concerns about environmental conservation. This chapter provides an overview of the identified potential to restore and utilize degraded land through an integrated biofuel- and food-production system that can also conserve the environment. Our findings highlight that the biofuel species Nyamplung (Calophyllum inophyllum L.) and Kemiri sunan [Reutealis trisperma (Blanco) Airy Shaw] in Indonesia are suitable to grow with local food crops on degraded land. Such integrated systems on degraded land are economically and socially favorable for local farmers. Producing biofuel and food on degraded land can also avoid compromising agricultural land use and production, while minimizing the harmful environmental consequences. However, for long-term sustainability of the system, and due to biodiversity and environmental concerns, there is a need to implement a mixed landscape approach using a “segregation” and “aggregation” land-management strategy, supported by competent government policies and local communities with sufficient social capital.
Evidence-based investment selection: Prioritizing agricultural development investments under climatic and socio-political risk using Bayesian networks
A review of the Enabling Environment for Transformative Land Investment in Ethiopia, Ghana and Mozambique
Sub-Saharan African development strategies emphasize optimizing agricultural and forestry resources through foreign and domestic investments in large-scale farms and plantations. While these land-based initiatives are believed to enhance economic development, concerns arise regarding their impact on marginalized groups and the environment. Issues like land tenure security and the agri-food sector’s investment climate play pivotal roles, highlighting the need for transparent and inclusive decision-making involving local communities.
The Rural Household Multiple Indicator Survey, data from 13,310 farm households in 21 countries
The Rural Household Multiple Indicator Survey (RHoMIS) is a standardized farm household survey approach which collects information on 758 variables covering household demographics, farm area, crops grown and their production, livestock holdings and their production, agricultural product use and variables underlying standard socio-economic and food security indicators such as the Probability of Poverty Index, the Household Food Insecurity Access Scale, and household dietary diversity. These variables are used to quantify more than 40 different indicators on farm and household characteristics, welfare, productivity, and economic performance. Between 2015 and the beginning of 2018, the survey instrument was applied in 21 countries in Central America, sub-Saharan Africa and Asia. The data presented here include the raw survey response data, the indicator calculation code, and the resulting indicator values. These data can be used to quantify on- and off-farm pathways to food security, diverse diets, and changes in poverty for rural smallholder farm households.
Agricultural lands key to mitigation and adaptation
Dominant tree species and earthworms affect soil aggregation and carbon content along a soil degradation gradient in an agricultural landscape
Guidelines for soil fertility management in Uganda
Human-elephant conflict hotspots in Assam: a rapid appraisal method
In India, human-elephant conflict has been on the rise for the last few decades. The situation is worse in the state of Assam, where 5719 elephants are present, and the density of elephants is greater than that of other areas. Most of the elephant habitats in the state are fragmented or intermingled with human-used lands. As a result, human-elephant conflict (HEC) has been increasing in the state. Each year, an average of 80 elephants and 70 humans die in the state because of HEC. Most of these conflicts occur during the paddy harvesting season. At that time of year, the elephants come out from their habitats and take refuge in forest patches and tea gardens near agricultural fields and raid crops at night. Different methods have been adopted to identify conflict-affected areas, but none of the studies have tried to identify all the HEC-affected areas in the state. Here, we provide a rapid appraisal approach for identifying HEC hotspots in the state by using published news information as the primary source of data. A total of 216 villages were identified as HEC-affected areas in Assam. The identified areas can be used to understand site-specific problems and for HEC mitigation practices, as these areas are currently limited to only a few areas.