Aboveground Net Primary Productivity in Grazed and Ungrazed pastures: Grazing Optimisation Hypothesis or Local Extinction of Vegetation Species

The controversy that has surrounded herbivory studies in the last few decades prompted our investigation to establish the extent to which herbivore optimisation hypothesis or compensatory growth evidence is real. We used the traditional movable cage method to collect primary productivity data on herbage, functional groups and key individual grass species in various controlled large herbivore treatments in an east African savanna. The herbivore treatments in triplicate blocks included cattle, wild herbivores with and without mega herbivores and combinations of cattle and wild herbivores also with and without mega herbivores. The findings revealed that at herbage level, most grazed treatments (four out of five) had higher productivity than the ungrazed control and three showed grazing optimisation curve at sixth polynomial degree between monthly productivity and grazing intensity (1-g/ng). At functional group level forbs productivity was higher in the ungrazed control than in any of the grazed treatments while at individual grass species level _Themeda triandra_ productivity was higher in all grazed treatments than in ungrazed control. We conclude against presence of herbivore optimisation hypothesis at herbage, functional group and species level because of lack of attributable grazing effect in grazed treatments that matches complex ecological effects in the ungrazed treatment

Community-Based Conservation: An Emerging Land Use at the Livestock-Wildlife Interface in Northern Kenya

In East Africa, an estimated 70% of wildlife populations are dispersed outside protected areas on community land. The way of life of the pastoralists, essentially support the thriving of wildlife. However, pastoralism is slowly transiting to more sedentary forms of livestock production. The region‘s wildlife populations future now largely depends on the conservation of habitats and migratory corridors on private and communally owned lands with competing land uses. Community wildlife conservancies are one of the approaches of decentralizing wildlife management and curbing biodiversity and habitat loss at the livestock-wildlife interface environments. Further, conservancies present an avenue for restoration of degraded grazing lands and improving pastoral livelihoods. This paper reviews the community-based conservation unfolding in northern Kenya using the case of Naibung’a Wildlife Conservancy in Laikipia County. Conservancies through land zoning and range rehabilitation have contributed to improved security of wildlife, people and their livestock. Conservancies’ success depends on continued investment in vegetation recovery, grazing management, livestock marketing and benefit sharing. The perceived threats facing conservancies are pasture scarcity, cattle rustling and human-wildlife conflicts. Conservation objectives and human livelihoods in Africa are closely interlinked and lessons learnt in Naibung’a Wildlife Conservancy could particularly be useful to other similar initiatives in Africa

Spatial Soil Loss Assessment Using USLE in Lake Ol Bolossat Catchment

Erosion by water is one of the most common types of soil degradation which occurs in all climatic regions and is widely considered to be a serious threat to the long-term viability of agriculture in many parts of the world. Lake Ol Bolossat in Nyandarua County, Kenya, is a high altitude lake that was formed on Rift Valley escarpment and faces the challenge of siltation due to increased soil erosion. Over the last few decades, the lake has been encroached and lake area has been overgrazed reducing the vegetation cover around the Lake. An assessment of spatial soil erosion loss was conducted using USLE model and GIS which showed that most parts of the Lake catchment have soil loss beyond tolerable levels of nine tons per year. The soil erosion range was between zero and 22, 525.5 tons per year. The land uses that were more vulnerable to soil loss are croplands, grazing lands with sparse vegetation and barelands which had soil loss ranges of 10–50 tons, 100 to 1000 tons and 500 to 22,525.5 tons per year respectively. The study recommended for immediate interventions by policy makers, researchers and development partners in curbing the soil loss problem

Effect of water conservation measures on soil moisture and maize yield under drought prone agro-ecological zones in Rwanda

This study was conducted to assess agricultural practices for generating maximum maize productivity in drought prone agro-ecological zones. The experiment was conducted in Cyili sub-catchment in Southern Province of Rwanda, which has an irregular rainfall distribution and a prolonged dry season. The experimental design consisted of a randomized design and each treatment was replicated three times. Findings from this study revealed that maize grain yield and yield components, such as plant height, cob diameter and length, number of leaves, 100 grain weight, and yield per plant were highly significantly affected (P  0.05). Supplementary irrigation treatment increased maize yield production to 11,982 kg ha-1. Mulching increased yield significantly to 8089 kg ha-1. Ridges yielded 5937 kg ha-1, and rainfed treatment yielded 4755 kg ha-1 of maize. Based on Pearson's correlation coefficients, grain yield and yield components were positively correlated and statistically significant (p < 0.001) under various water conservation methods. Supplementary irrigation through rainwater harvesting was found to be a more promising option for maize growers to mitigate dry spell and stabilize maize production in rainfall deficient agro-ecological conditions not only in Rwanda, but in sub-Sahara Africa. Keywords: Maize yield, Mulching, Tied ridges, Supplementary irrigatio

Enclosures as a land management tool for food security in African drylands

Increasing sedentary agro-pastoralist livelihoods may be explained by land degradation, population pressure, agricultural commodification, and economic development. We reviewed scientific and grey literature for the effects of enclosures on food security. Only 8% of the 114 reviewed scientific articles addressed food production, while 69% approached environmental parameters that indirectly affect food security, most of which had positive results. Thirty-one percent focused on social and economic impacts, land tenure conflicts and elite capture with negative connotations. The grey literature showed an opposite balance between positive environmental views and negative socio-economic impacts. Enclosures are not a panacea for dryland development, but their use need to be recognized and understood. Multidisciplinary research and cooperation on the applied management of enclosures in the context of food security is highly needed. Furthermore, agro-pastoralist land-use practices need more policy space and practical management support, such as clear tenure legislation, agroforestry methodologies, and support in fodder production systems.Funding Agencies|Vetenskapsradet [SRL 348-2014-4288]</p

Modelling surface runoff using the soil conservation service-curve number method in a drought prone agro-ecological zone in Rwanda

Runoff farming is reported to improve land productivity and crop yields in hot and dry climates. This study was conducted to assess the available rainwater that can be harvested in a conserved catchment in a drought prone agro-ecological zone. The study was carried out in the Cyili sub-catchment, southern province of Rwanda, which has an irregular rainfall pattern and unexploited runoff water. Soil Conservation Service-Curve Number method (SCS-CN), CROPWAT model version 8 and Hazen model with an average daily rainfall data recorded from 1971 to 2016 were applied to estimate the runoff and water requirements in the study area. Findings of the study revealed that more than half rainfall water received in the catchment was lost through runoff (229.8 mm) and effective rainfall was lower (246.9 mm) than the actual crop water requirement for maize (330 mm). The expected seasonal surface runoff volume to be harvested by the farmers was 3008 m3 ha−1 per season and 1.29 × 106 m3 per season for the entire whole sub-catchment (430 ha). Based on Hazen model, the return period of low rainfall (dry spell) event would be expected every 2 years with a 98% probability of occurrence. Cyili sub-catchment has higher potential runoff volume to stabilize the deficit of water demand in the period of short rainy season. This suggests that rainwater harvesting through supplementary irrigation is an option to improve the crop yield in the dry period as well as in the annual dry season. Keywords: Available rainwater, Cyili sub-Catchment, Curve number, Runoff, Rwand

THE CANOPY EFFECTS OF Prosopis juliflora (DC.) AND Acacia tortilis (HAYNE) TREES ON HERBACEOUS PLANTS SPECIES AND SOIL PHYSICO-CHEMICAL PROPERTIES IN NJEMPS FLATS, KENYA

The canopy effects of an exotic and indigenous tree species on soil properties and understorey herbaceous plant species were investigated on the Njemps Flats, Baringo district, Kenya. Samples of soil and herbaceous plant species were obtained within the canopies of systematically selected P. juliflora (exotic) and A. tortilis (indigenous) trees, and from adjacent open areas. Standing biomass, frequency and cover of understorey plant species were significantly (

Impact of ownership of water resources and associated facilities to its access and management in the asal Kitui County, Kenya

In Kenya, where 80% of the land is arid and semi-arid, access to water is an everyday challenge for majority of the people. Methods used to improve access to water in Kenya results to different, and sometimes unexpected outcomes. The water resources assessed have come about through interventions by various agents, majority donor funded. These agents use various models resulting to different outcomes. We assessed technologies used to improve access to water in the Asals of Kitui County, Kenya. The technologies were classified into four; individual, private, community and government owned. Those assessed were tanks, boreholes and hand dug wells, sand dams and pipelines for individual, private, community and government owned respectively. Private and individual resources outperformed others in terms of management with donor aided community owned being the least sustainable. Government owned water facilities reached relatively more people and although unreliable were the most trusted source to those covered by the infrastructure. Individual owned water resources offered water in small quantities, the main benefit being owners were able to manage with ease through rationing to stretch availability for a long time. Donor funded community owned resources suffered vague ownership models making their management and maintenance impossible. Privately owned resources offered the best solution as water was sold and the resulting money become income for the owners as well as providing resources for maintenance. The resulting income offered incentives for further investment which further improved access. The tragedy with privately owned water resources was that the poor paid too much for water while the rich continued to accumulate massive wealth. To ensure adequate access to water especially in remote places, privately owned and operated systems should be encouraged and supported but with government sponsored regulations to ensure the poor are not exploited.Water Resource

Enhancing soil organic carbon, particulate organic carbon and microbial biomass in semi-arid rangeland using pasture enclosures

Abstract Background Rehabilitation of degraded rangelands through the establishment of enclosures (fencing grazing lands) is believed to improve soil quality and livelihoods, and enhance the sustainability of rangelands. Grazing dominated enclosure (GDE) and contractual grazing enclosure (CGE) are the common enclosure management systems in West Pokot County, Kenya. Under CGE, a farmer owning few animals leases the enclosure to households with relatively more livestock, while GDE is where the livestock utilizing the enclosure are purely owned by the farmer. Livestock management in both systems is via the free-range system. This study evaluated the effect of enclosure management on total soil organic carbon (SOC), particulate organic carbon (POC) and microbial biomass carbon (MBC) and nitrogen (MBN) as key indicators of soil degradation at 0–40 cm depth. The two enclosure systems were selected based on three age classes (3–10, 11–20 and > 20 years since establishment) (n = 3). The adjacent open grazing area (OGR) was used as a reference (n = 9). Results Relative to OGR, the pasture enclosures significantly decreased soil bulk density and increased the concentrations of total organic C, POC, MBC and MBN compared to the degraded OGR (P < 0.001). Significantly higher concentrations of POC and MBC was recorded in GDE than CGE (P = 0.01). The POC accounted for 24.5–29.5% of the total SOC. MBC concentrations ranged from 32.05 ± 7.25 to 96.63 ± 5.31 µg C g−1 of soil in all grazing systems, and was positively correlated with total SOC and POC (P < 0.001). The proportional increase in POC and MBC was higher in GDE (56.6 and 30.5% respectively) compared to CGE (39.2 and 13.9% for POC and MBC respectively). Conclusions This study demonstrated that controlling livestock grazing through the establishment of pasture enclosures is the key strategy to enhance total SOC, POC, MBC, and MBN in degraded rangelands; a precondition for improving soil quality. Therefore, the establishment of enclosures is an effective restoration approach to restore degraded soils in semi-arid rangelands