Soil organic carbon management for sustainable land use in Sudano-Sahelian West Africa

Abstract

Judged by their negative nutrient balances, low soil cover and low productivity, the predominant agro-pastoral farming systems in the Sudano-Sahelian zone of West Africa are highly unsustainable for crop production intensification. With kaolinite as the main clay type, the cation exchange capacity of the soils in this region, often less than 1 cmol c kg −1 soil, depends heavily on the organic carbon (Corg) content. However, due to low carbon sequestration and to the microbe, termite and temperature-induced rapid turnover rates of organic material in the present land-use systems, Corg contents of the topsoil are very low, ranging between 1 and 8 g kg −1 in most soils. For sustainable food production, the availability of phosphorus (P) and nitrogen (N) has to be increased considerably in combination with an improvement in soil physical properties. Therefore, the adoption of innovative management options that help to stop or even reverse the decline in Corg typically observed after cultivating bush or rangeland is of utmost importance. To maintain food production for a rapidly growing population, targeted applications of mineral fertilisers and the effective recycling of organic amendments as crop residues and manure are essential. Any increase in soil cover has large effects in reducing topsoil erosion by wind and water and favours the accumulation of wind-blown dust high in bases which in turn improves P availability. In the future decision support systems, based on GIS, modelling and simulation should be used to combine (i) available fertiliser response data from on-station and on-farm research, (ii) results on soil productivity restoration with the application of mineral and organic amendments and (iii) our present understanding of the cause-effect relationships governing the prevailing soil degradation processes. This will help to predict the effectiveness of regionally differentiated soil fertility management approaches to maintain or even increase soil Corg levels.

Land Cover, Extent, and Properties of Arenosols in Southern Africa

“…Under natural conditions and in arid and semi-arid areas, it is difficult to establish dense plant communities on Arenosols due to the exploitation for firewood, grazing, or the destructive effects on the tree layer by large vertebrates and periodic burning (Almendros et al, 2003). As many Arenosols are inherently poor and are cultivated with limited or no nutrient inputs (Bationo and Buerkert, 2001;Mokwunye, 1991;Stoorvogel, Smaling, and Janssen, 1993), these soils are generally not very productive.…”

Climate Smart Agriculture as Final Goal: Use of Improved Cereals Varieties in Cinzana, Mali.

“…Among several strategies, utilization of adapted improved available and accepted varieties by farmers and water conservation techniques are relevant as climate change adaptation measures. In fact, 20 to 40 percent of annual rainfall is lost as runoff leading some times to severe erosion (Tacko Kandji et al, 2006) and globally only 10% -15% of rainfall will be used by crops for transpiration (Bationo and Buerkert, 2001). To tackle the problem , several, proven soil and water conservations techniques that restore degraded lands and improve water infiltration in the soil (Gigou et al, 2006;Zougmore et al, 2014) and agroforestry technologies that restore soil fertility and control soil erosion were also developed (Bayala et al, 2012) to help farmers adapt to climate change.…”

Status of Soil Fertility in a Community Forest of Nepal

“…Soil fertility is poor in most of the field sites monitored in the Special Programme in Nepal (SPIN) (Ghani & W., 1997). Data from many long-term experiments in upland soils shows that yield had declined due to decrease in SOC, soil acidification and a decrease of nutrient use efficiency (Bado et al, 2010;Batino, 2008). Gregory, (1995) highlighted the need for research to address the issues of soil fertility management in Nepal.…”