Application of zai and rock bunds in the northwest region of Burkina Faso: study of its impact on household level by using a stochastic linear programming model

Abstract

Agricultural production in the NW Burkina Faso is seriously endangered by soil erosion and an overall decline in soil fertility. In the past 15 years various anti-erosion methods have been adopted in this region with some success. The widespread promotion of rock bunds is an important example. Land conservation methods alone without increased efforts to maintain (or to increase) soil fertility levels does not suffice in the long run. The potential impact of a combination of rock bunds and zai, a local technology to improve water infiltration and efficiency of manure application, was investigated. The analysis is carried out at farm level with a stochastic linear programming model. It includes sequential decision making to cope with rainfall risks. The study shows the important potential of rock bunds and application of zai, and limitations due to labour and manure constraints. The techniques are largely applied on common fields. Changes in labour organization and use of manure have to be introduced before women may profit from these techniques on their individual fields. The results show that the impact on farm-level food security is more limited than is sometimes supposed on the basis of a simple extrapolation of plot-level results.

Soil and Water Conservation in Burkina Faso, West Africa

“…The above results demonstrate that SWCM rehabilitate degraded lands, substantially increasing crop productivity [32]. 1980-1988 zai/stone bund/half-moon North and Sahel 600-700 [82] 1986-2000 zai/half-moon sahel 1000-1500 [85,100] 1984-2001 zai/stone bunds/half-moon Centre-north/North 611-793 [71,73] 1975-1985 zai Central plateau 400-500 [118] An analysis of results from other peer-reviewed publications showed that zais cover a total land area of 30,000 to 60,000 ha in northwestern Burkina Faso [58] and more than 200,000 ha of agricultural land in central Burkina Faso [32]. The adoption rate of zais in Yatenga province was between 49% and 60% [137].…”

“…The construction of stone bunds started in the late 1970s and early 1980s by the OXFAM-funded Agroforestry project in Yatenga, which was identified as having mostly highly degraded agricultural lands [32]. Between the 1970s and 1980s, only 2% of cultivated areas were equipped with stone bunds in order to improve water infiltration and to reduce the runoff potential, thus protecting the topsoil against erosive action [75,[81][82][83]. The purpose was to develop water harvesting techniques to increase soil productivity and to eventually rehabilitate gullies, subsequently reducing the rate of land degradation [84].…”

Ecosystems protecting infrastructure and communities: lessons learned

“…There are several examples in the scientific literature on the effectiveness of the endogenous practices implemented as part of EPIC in Burkina Faso. Regarding zaï, previous studies and comparisons with untreated farms has shown that they are effective in increasing cereal yields particularly when implemented on degraded soil (Maatman et al, 1998;Somé et al, 2004). Constructions of stone bunds are documented to reduce run off and soil loss by about 12 % and 45 % respectively (Zougmoré et al, 2003).…”

“…Constructions of stone bunds are documented to reduce run off and soil loss by about 12 % and 45 % respectively (Zougmoré et al, 2003). Maatman et al (1998) found that the combinations of Zaï and stone bunds were mutually reinforcing technologies to conserve water and land. A small study conducted at the EPIC sites showed similar results, noting for example that sorghum yield with zaï alone was 1290 Kg/ha while it was 1330 Kg/ha for stone bunds that was used in combination with zaï by several farmers (APROS, 2016).…”

Optimal Spacing of Soil Conservation Barriers

“…yields with bund spacings varying from 10 to 50 m. Vlaar (1992) reports doubling of yields in some cases when rock bunds are constructed. Hulugalle et al (1990) and Maatman et al (1998) indicate that the impact of rock bunds is substantially enhanced when combined with other and water conservation techniques such as tied ridges and za ı ˆ (an intensive manure management method).…”