Land cover change and its relation with population dynamics in Burkina Faso,West Africa

In the tropics, conversion of woodland and forest into cropland and pasture has risen drastically during the last decade. Rapid population growth and poverty are believed to be the main factors of change in land use in these zones. Southern Burkina Faso experienced rapid population growth due to massive peasants' migration from the north and central regions of the Country, exacerbated by decreasing rainfall and arable land in the area of origin. This paper assessed the impact of such increased population on land use change in the attracting zones from 1986 to 2006. Satellite images were used to measure changes in land cover types over time and national population census data were used to examine the population dynamics over the same time. Results showed that the forest land was progressively converted to croplands at an annualized rate of 0·96 per cent, while the population density shifted from 17 inhabitants per km² in 1986 to 30 inhabitants per km² in 2006. Pearson correlation analysis revealed the positive role of population size and distribution in explaining land cover change. Policy initiatives that will lead to better environmental management are recommended. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of combined water and nutrient management on runoff and sorghum yield in semiarid Burkina Faso

Abstract. In the semiarid regions of sub-Saharan Africa, fertilizer recovery and nutrient release from organic sources are often moisture limited. Moreover, in these regions runoff brings about large nutrient losses from fertilizer or organic inputs. This study was conducted in the north sudanian climate zone of Burkina Faso (annual rainfall 800 mm, PET 2000 mm yr⁻¹). We assessed the combined and interactive effects of two types of permeable barriers (stone rows and grass strips of Andropogon gayanus Kunth cv. Bisquamulatus (Hochst.) Hack .) and organic or mineral sources of nitrogen on erosion control and sorghum yield. The field experiment (Ferric Lixisol, 1.5% slope) was carried out during three rainy seasons and consisted of 2 replications of 9 treatments, in which the barriers were put along contours and combined with compost, manure and fertilizer nitrogen (N). Compared with the control plots, the average reduction in runoff was 59% in plots with barriers alone, but reached 67% in plots with barriers + mineral N and 84% in plots with barriers + organic N. On average, stone rows reduced soil erosion more than grass strips (66% versus 51%). Stone rows or grass strips without N input did not induce a significant increase of sorghum production. Supplying compost or manure in combination with stone rows or grass strips increased sorghum grain yield by about 142%, compared with a 65% increase due to mineral fertilizers. The sorghum grain yields at 1 m upslope from the grass strips were less than those 17 m from the grass strips. As stones do not compete with plants, the opposite trend was observed with stone rows. We conclude that for these nutrient depleted soils, permeable barriers improve nutrient use efficiency and therefore crop production. However, grass strips must be managed to alleviate shade and other negative effects of the bunds on adjacent crops.     

Long-term effect of ploughing, and organic matter input on soil moisture characteristics of a Ferric Lixisol in Burkina Faso

Soil moisture characteristic curves were determined in long-term trials at the agronomic research center of Saria (latitude 12°16′ N, longitude 2°09′ W) in West-central Burkina Faso. The agronomic treatments combined soil tillage with organic and chemical fertilizers. The twin values for soil moisture and water potential showed that on ploughed plots, moisture content was higher at low suction and lower at high suction than the hand hoed plots. Moisture contents were higher for extreme suctions (pF < 1.5 and >3) on plots that received high dose of animal manure. The bush fallow plots behaved as a ploughed plot at low suction and like a hand hoed plot at the high suction. Field capacities were around 9.50% (g/g) and 8% (g/g), respectively, for hand hoed and ploughed plots, while the wilting points for both were of 5–6% (g/g). Organic matter input improved field capacity and soil water content at wilting point but not the useful available water (UAW). The UAW ≥10 mm on the fallow and the control, while it was <9 mm on the other treatments in 0–20 cm soil layer. Soil structural modifications induced by tillage and organic matter input explained these differences in soil hydrologic regime.     

Farmers' perceptions of the role of scattered vegetation in wind erosion control on arable land in Burkina Faso

This paper describes the results of a survey on farmers' perceptions of the effect of woody natural vegetation on wind erosion. Sixty farmers were interviewed in three villages in northern Burkina Faso. The farmers mentioned that the presence of woody vegetation between the crops could benefit yield, but feared competition between the natural vegetation and the crop. Vegetation in a field was considered to increase deposition and decrease erosion on that field. The most important vegetative characteristics that affect wind erosion were, according to the farmers, vegetation's shape, porosity, flexibility and arrangement of the vegetation in the field. At present, most farmers do not apply this knowledge to the management of the natural woody vegetation on their fields. Copyright © 2005 John Wiley & Sons, Ltd.     

Effectiveness of combined application of Kodjari phosphate rock,water soluble phosphorus fertilizer and manure in a Ferric Lixisol in the centre west of Burkina Faso

Increasing soil phosphorus and organic matter content for crop production while reducing the cost of production are required to facilitate the achievement of green revolution in Africa. Field and pot experiments were laid out during 2012 and 2013 to assess the effects of combined application of Kodjari phosphate rock (PR) and water soluble phosphorus on sorghum yields, P uptake and Lixisol characteristics in the centre west of Burkina Faso. Five P fertilizers treatments (zero P, 100% TSP (triple super phosphate), 100% PR, 50% PR + 50% TSP, 75% PR + 25% TSP) and two cow manure treatments (zero, 5 t ha^?1) were tested. In field experiment, 50% PR + 50% TSP was as effective as 100% TSP in increasing sorghum yield above the control by 30% in 2012 and 50% in 2013 and P uptake by 30% in both years. Manure had an additive effect on phosphorus fertilizers in increasing sorghum yields and P uptake. In pot experiment, increases of Ca uptake, soil pH and microbial P were observed with the application of 50% PR + 50% TSP. Our results suggest that formulation of fertilizer combining phosphate rock and mineral P would improve sorghum yields and income of smallholders.     

Population structure of three woody species in four ethnic domains of the sub‐sahel of Burkina Faso

In developing countries many people depend on woody resources for their livelihoods. Monitoring human impact on the populations of socio‐economically important species is therefore important for the conservation of vulnerable plants. In order to assess and compare the population structure and regeneration patterns of three multipurpose species, namely Acacia seyal Del., Balanites aegyptiaca Delile and Pterocarpus lucens Lepr. in four ethnic areas of the sub‐Sahel of Burkina Faso (Samo, Gourmantché, Fulani and Mossi), we used the size‐class distribution method (SCD) (Condit et al., 1998 ). Diameter at breast height (Dbh) of adult individuals of each species were sampled on 1000 m² (20 m × 50 m) plots in each ethnic domain. Recorded Dbhs were distributed among eight size‐classes of 5 cm intervals. For each species, the slope of the regression of the SCD was considered to be an indicator of the population structure. Seedlings and saplings were recorded on five nested 25 m² plots and fell into five height classes of 0·5 m intervals. The target species had significant (p < 0·001) negative SCD slopes with an inverse J‐shape distribution in all ethnic areas; indicating stable populations with good regeneration. Kruskal–Wallis test for the SCDs of A. seyal, B. aegyptiaca and P. lucens did not differ significantly among the ethnic areas (p > 0·1). This suggests that the dynamics of each of the three species is similar across ethnic domains and the sub‐Sahel. Data from P. lucens depicted an apparent stable population structure which contrasted with our field observations, perception of local people and previous studies. Copyright © 2010 John Wiley & Sons, Ltd.     

A decade of non-sorted solid urban wastes inputs safely increases sorghum yield in periurban areas of Burkina Faso

Abstract

Non-sorted solid urban wastes (SUW) are used by periurban cereal farmers in Africa. There is however limited information on how these SUW affect soil quality and cereal production and quality. In order to answer this question we identified around Ouagadougou (Burkina Faso) sites cultivated with sorghum (Sorghum bicolor (L.) Moench) that had received SUW for less than 5 years, for more than 5 years and less than 10 years and for more than 10 years. We sampled soils at 0–15 and 15–30 cm depth and we analysed pH, total carbon (C), nitrogen (N) and inorganic phosphate (P) content and P and heavy metals availability. We also measured at some of these sites sorghum production and nutrient and metal contents in sorghum grain and straw. Our results show that the 0–15 cm horizon of the soils that had received SUW for less than 5 years had lower pH, available P and heavy metals contents and produced lower yields than those that had been amended with SUW for more than 10 years. Maximum grain yield was observed in the sites that had been amended for more than 5 years but less than 10 years. There were no clear effects of SUW application time on the heavy metal contents of sorghum grain and straw. The increases in nutrient and heavy metals content observed in the 15–30 cm horizon of soils that had been amended for more than 10 years point out to the risks of element transfer to deeper horizons. Our results suggest that a complete sorting of organic matter from SUW and its further composting as presently recommended, is not necessary. Simply removing dangerous items from the SUW such as plastics, glass and batteries, would be sufficient. Adding this sorted substrate for 5 to 10 years to cereal fields would be sufficient to reach optimal yields, thereafter this substrate should be added to other surfaces.     

The impact of ecotourism on livelihood and natural resource management in Eselenkei,Amboseli Ecosystem,Kenya

This paper presents the impact of ecotourism on livelihood and natural resource management in the periphery of Amboseli Biosphere Reserve in Kenya. Ecotourism initiatives that have been introduced by Porini Ecotourism, a private investor, are benefiting Eselenkei Group Ranch in terms of income, improved infrastructure, employment opportunities and exposure. Over US$5000 is received annually as land rent, gate fee and bed charges. Twenty‐six Maasai men are employed for the upkeep of project facilities. The community's capacity to facilitate resource‐related conflicts has improved following support from development institutions. An expanding livelihood base is reducing local vulnerability to disaster and people–wildlife conflicts. The numbers of resident wildlife species in the conservation area have increased due to regeneration of woody species and reduced frequency of livestock. Despite the achievements, ecotourism is threatened by cultivation. The latter is jeopardizing conservation efforts, as the area frequented by wildlife is being lost and people–wildlife conflicts intensified. Another dilemma is that the Eselenkei community is not effectively participating in ecotourism a situation that is associated with inadequate management and negotiation skills in the group ranch committee. The latter requires leadership and microenterprise management skills if earnings from ecotourism are to be effectively invested in alternative sources of livelihood, to reduce current and potential conflicts. There is also need to build the community's capacity for the promotion of activities that compliment ecotourism. Frequent breakdown of community boreholes lead to dependence on the conservation area for water during prolonged drought, intensifying conflicts between livestock and wildlife.

1 Referring to low‐impact nature‐based tourism packages that benefit local communities and the national government while helping to conserve the resource base (Kenya Wildlife Service (KWS), unpublished report, 2001).

Copyright © 2002 John Wiley & Sons, Ltd.     

The sacred commons: Conflicts and solutions of resource management in sacred natural sites

Sacred natural sites are considered an additional pillar for biodiversity conservation, next to the protected areas network. However, sacred landscapes are not primarily conservation areas, but exist for cultural and social reasons. To evaluate their strengths and weaknesses as community-based conservation areas, a thorough understanding of the underlying values, institutional arrangements, and outcomes is required. Here, I use institutional economics for a meta-analysis of publications on sacred natural sites to identify potential conflicts in their maintenance, and to analyze institutional arrangements to solve these conflicts. I show that most sacred natural sites resemble common-pool resources and that many design principles that are linked to common-pool resources are also found in traditional institutions managing sacred places. Design principles are no blue-print solution but they may guide future research to identify locally robust institutional arrangements that are linked to the ecological integrity of sacred natural sites.     

The effect of development interventions on the use of indigenous range management strategies in the Borana Lowlands in Ethiopia

In the last three decades, the Borana rangelands of Southern Ethiopia have been deteriorating due to unsustainable utilization. This paper analyses the changes in indigenous range management among the Borana pastoralists and the role of development interventions. The fieldwork was carried out during 2000–2002, following a severe drought. Two locations, Dida Hara and Web, that once were part of a large grazing system with seasonally distinct herd movements, experienced differences in development interventions. Indigenous range management strategies and pastoralists' current use of key strategies before and after the last drought were compared based on pastoralists' information about land‐use change collected through participatory appraisals, land‐use mapping, and household surveys. Priorities for future interventions were discussed in multi‐stakeholder workshops. Water development in rainy season grazing areas such as Dida Hara has resulted in year‐round grazing and expansion of permanent encampments. This has affected the traditional dry‐season areas like Web because it interrupted the organization of rangeland management. Herd mobility became less applicable and traditional land‐use classifications have lost their function in range management. The introduction of government‐imposed administration disturbed the indigenous institutional networks and negotiation procedures for controlled herd movements. Aggravated by human population growth, this reinforces a higher and more permanent grazing pressure, leading to the deterioration of rangelands. Despite the disturbance of pastoralists' range management practices considerable technical and management capabilities prevail. Innovative development approaches should integrate indigeneous knowledge‐based (IK) strategies and formal legislation, but this requires strong external support and official recognition from the Ethiopian Government. Copyright © 2007 John Wiley & Sons, Ltd.