Quantifying the impact of land degradation on crop production: the case of Senegal

Abstract

Abstract. Land degradation has been a persistent problem in Senegal for a long time and by now has become a serious impediment to long term development. In this paper, we quantify the impact of land degradation on crop yields using the results of a nation-wide land degradation assessment. For this, the study needs to address two issues. First, the land degradation assessment comprises qualitative expert judgments that have to be converted into more objective, quantitative terms. We propose a land degradation index and assess its plausibility. Second, observational data on soils, land use and rainfall do not provide sufficient information to isolate the impact of land degradation. We, therefore, design a pseudo-experiment that for sites with otherwise similar circumstances compares the yield of a site with and one without land degradation. This pairing exercise is conducted under a gradual refining of the classification of circumstances, until a more or less stable response to land degradation is obtained, In this way, we hope to have controlled sufficiently for confounding variables that will bias the estimation of the impact of land degradation on crop yields. A small number of shared characteristics reveal tendencies of "severe" land degradation levels being associated with declining yields as compared to similar sites with "low" degradation levels. However, as we zoom in at more detail some exceptions come to the fore, in particular in areas without fertilizer application. Yet, our overall conclusion is that yield reduction is associated to higher levels of land degradation, irrespective of whether fertilizer is being applied or not.

Sustainable land management policy to address land degradation: linking old forest management practices in Senegal with new REDD+ requirements

“…However, the Land Degradation Assessment (LADA) (2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013), a UNEP funded project for FAO and other similar studies (Ribot, 2002) attempted to provide basic information on land degradation to identify potential areas for conservation that can be used as initial REDD + implementation sites. Sonneveld et al (Sonneveld et al, 2010), estimated that 34% of Senegal non-built land is considered degraded. Of this, 4.5% is slightly degraded, 24% is moderately degraded, and 5.6% is heavily degraded (Sonneveld et al, 2012).…”

“…Of this, 4.5% is slightly degraded, 24% is moderately degraded, and 5.6% is heavily degraded (Sonneveld et al, 2012). Degraded land represents 58% of the 9 015 000 ha of agricultural land (Ndiaye et al, 2013) (Sonneveld et al, 2010).…”

Soil quality assessment via the factor analysis of karst rocky desertification areas in Hunan, China

“…Previous studies primarily focused on single or multiple soil physicochemical properties to determine soil fertility in KRD areas (Cheng et al, 2016; Li et al, 2017; Sheng et al, 2016; Tesfahunegn, 2016). Sonneveld et al (2016) developed a land degradation index and assessed its plausibility in Senegal, in which soil physical and chemical properties were not mentioned. Nevertheless, SQ is affected by various soil factors that cannot be evaluated based on individual soil properties (Wang et al, 2018).…”

The impact of land use and cover change on soil organic carbon and total nitrogen storage in the Heihe River Basin: A meta-analysis

“…Houghton et al (2012) showed that the amount of SOC loss due to the LUCC was as high as 12.5% of the anthropogenic carbon emissions from 1990 to 2010. In parallel, land degradation caused by SOC loss may damage ecosystem structure and function (Costantini et al, 2016) and directly influence the hydrological and biogeochemical cycles in the earth system (García Díaz et al, 2016;Sonneveld et al, 2016). In summary, the changes in SOC and TN due to the LUCC are critical for maintaining ecosystem sustainability, which should be evaluated scientifically.…”