Geographical and ecological setting
Located in the western center of the Sahel belt, Niger is landlocked by seven countries. The Sahel forms a semi-arid interface from the Atlantic Ocean to the Red Sea, a transition zone between the arid Sahara desert to the north and savannas (and eventually tropical forests) to the south. The Sahel’s high temperatures, unreliable rainfall and low soil fertility pose significant challenges for food production (Danjuma & Dara'u, 2013).
Maradi, our case study area, is a rural administrative region in south-central Niger, covering an area of approximately 41,800 km along the border with Niger’s other regions, Tahoua and Zinder, and northern Nigeria (Tougiani et al., 2009). With an estimated population of 2.8 million (2008 estimate), Maradi is the most densely populated region in Niger and consists mainly of savanna, sandy dunes and plains (Tougiani et al., 2009).
Average annual rainfall in Maradi is between 250 mm and 500 mm (from north-to-south gradient) with high inter-annual variability (Tougiani et al., 2009). Water availability is a significant constraint in rain-fed agriculture production of Maradi (ISSS, 1998). Drought with erratic rainfall events causes soil erosion, low water use efficiency, and crop pest invasions (Tougiani et al., 2009). Since the severe drought in 1970s – 1980s, rainfall has increased, which appears to have helped the re-greening of Maradi (World Bank, 2009). However, the average annual rainfall has decreased over the last 72 years. And, the mean temperature ranges from 23.5 degrees Celsius to 32.7 Celsius during dry season (Funk et al., 2012). The temperature sometimes exceeds 40 Celsius degrees, which often resulted in failings of seedlings planted (Trouginai et al. 2009).
Dominant soil in Maradi is sandy Arenosols and has very little organic matter. The Arenosols is highly permeable while easily compacted and has low water-holding capacity (ISSS, 1998). Regenerated trees, through FMNR, have improved soil fertility and water retention in soils. Fallen leaves, twigs, and branches function as mulch, providing nutrients and protecting against soil erosion. Increased root mass holds soil and moves nutrients up to the surface level from deeper layers (Sendzimir et al., 2011). Regenerated trees also catch minerals and silt that pass in the wind (Issiaka et al., 2012). Moreover, tree shade provides shelter for livestock such as goats whose manure in turn is a great nutrient source for trees and neighbouring plants (Rinaudo, 2011).
Dominant vegetation communities in Maradi are steppe zone of grass, brush and thicket in its northern region and brush-grass savanna zone in the south. Dominant native tree species include Bauhinia reticulata, Guiera senegalensis, Combretum spp., and Ziziphus spp. They are most commonly used for firewood, poles, fodder for animals and fruit (Cunningham et al., 2005; Rinaudo, 2012; Semalulu et al., 2011; Tougiani et al., 2009). Nearly 30,000 km2 of woodlands or open forests in Maradi have been cleared and transformed to agricultural fields over six decades. As of 1996, 73% of lands in Maradi was already used for cultivation (Mortimore & Turner, 2005). Dominant crop species are millet (Pennisetum glaucum), sorghum (Sorghum bicolor), cowpeas (Vigna vaguiculata), peanuts (Arachis hypogaea), hibiscus (Hibiscus sabdariffa), and cassava (Manihot esculenta) ((B. P. Cunningham, 2010).
Drought, erratic rainfall patterns, windstorms, low soil fertility and water retention are ecological drivers for desertification in Maradi (Walsum & Berg, 2014). However, land mismanagement (including overgrazing) is a significant cause for desertification (P. J. Cunningham et al., 2005; Tougiani et al., 2009).
The FMNR farmlands have an average of 8 tree species with a density of 32 individuals per hectare. The crop species are planted in rotation between the tree rows in FMNR lands (Cunningham et al., 2005; Tougiani et al., 2009). They have higher tree diversity by 1-3 species and tree density by 12-16 individuals per hectare than non-FMNR lands (Haglund et al., 2011).
Located in the western center of the Sahel belt, Niger is landlocked by seven countries. Maradi has primarily Dry subhumid and semiarid systems. Source: http://lca.usgs.gov/lca
Source: Defourny et al. (2009) The Maradi region is the darker brown polygon in the map.
Nearly 30,000 km2 of woodlands or open forests in Maradi have been cleared and transformed to agricultural fields over six decades. As of 1996, 73% of lands were already used for cultivation. Source: http://lca.usgs.gov/lca/
Source: Sendzimir et al. (2011) From 1970 to late 1985, the rainfall isohyets of 100 mm and 500 mm moved southward, which resulted in severe drought, food riot, and deadly famine (Sendzimir, Reij, et al., 2011). Since the late 1980s, rainfall has improved, which appears to have helped re-greening of Maradi (World Bank, 2009); still, the average annual rainfall has decreased over the last 72 years.