Assessing the effect of Faidherbia albida based land use systems on barley yield at field and regional scale in the highlands of Tigray, Northern Ethiopia

Abstract

Implications of changes in traditional Faidherbia albida based land use systems on productivity were investigated in Tigray, northern Ethiopia. The relation between F. albida based-land use systems and crop productivity was explored in 77 fields and 81 farms at field and regional scales, respectively. Barley yield and soil fertility increased when field locations were closer to a F. albida trunk in the F. albida alone (AA) and F. albida + livestock (AL) land use systems. However, the F. albida + Eucalyptus camaldulensis (AE) land use system showed a decreasing trend in barley yield and soil fertility as distance from a F. albida trunk decreased. At regional scales, higher F. albida tree density per farm and sparsely cultivated land use types were associated with increased potential ecosystem services (barley yield). This study suggests that local biodiversity components (e.g. F. albida trees) can increase crop yield and soil fertility significantly when grown within and around farm lands. This study contributes to the knowledge on agricultural productivity enhancement by developing an approach to scaling up from farm to regional level.

Soil Quality Indices for Evaluating Smallholder Agricultural Land Uses in Northern Ethiopia

“…trees are among the most selected ones in the region. Nowadays, farmers grow these trees in and around their farmlands in order to improve soil fertility and increase crop yields [10].…”

Spatial variation in biodiversity, soil degradation and productivity in agricultural landscapes in the highlands of Tigray, northern Ethiopia

“…Soil degradation is estimated as visible soil erosion (Hadgu et al 2008a). Based on our previous studies in this region (Hadgu et al 2008a(Hadgu et al , 2008b(Hadgu et al , 2008c, we hypothesize that agro-biodiversity and crop productivity have declined in recent years, while soil erosion has increased. To test these hypotheses, on-farm surveys were conducted in 2005, and the data were, as much as possible, compared with similar data collected in 2000 (Hadgu et al 2008a).…”

“…These cropping systems included regularly spaced acacia trees, and resulted in higher caloric crop yields thanks to the nitrogen-fixing bacteria associated with acacia trees. The beneficial effects of acacia trees on barley yields were demonstrated in separate experiments (Hadgu et al 2008c). Higher overall productivity per unit area can also be obtained when different species efficiently utilize nutrients, water and light because of their interspecific differences, resulting in complementarity and facilitation (Tilman et al 1996;Picasso et al 2008).…”

“…3) demonstrate that the type of land that is sparsely cultivated is positively associated with high agrobiodiversity, while the type that is intensively cultivated is associated with medium and particularly with low agrobiodiversity. Earlier results (Hadgu et al 2008c) showed that removal of the traditional tree species associated with intensification also removes significantly positive effects on yield of crops. Thus, a greater reliance on external nutrients first has to overcome this loss of ecosystem service, which may be one of the factors explaining lower caloric production in the more intensive systems in this study.…”

“…Chew.) compared to locations outside the tree canopy for different A. albidabased land use systems (Hadgu et al 2008c). This indicates that the presence of trees contributes to crop productivity at the prevailing production levels, and challenges policies promoting the sole reliance on external inputs.…”