Communicating complexity: Integrated assessment of trade-offs concerning soil fertility management within African farming systems to support innovation and development

Abstract

a b s t r a c tAfrican farming systems are highly heterogeneous: between agroecological and socioeconomic environments, in the wide variability in farmers' resource endowments and in farm management. This means that single solutions (or 'silver bullets') for improving farm productivity do not exist. Yet to date few approaches to understand constraints and explore options for change have tackled the bewildering complexity of African farming systems. In this paper we describe the Nutrient Use in Animal and Cropping systems -Efficiencies and Scales (NUANCES) framework. NUANCES offers a structured approach to unravel and understand the complexity of African farming to identify what we term 'best-fit' technologiestechnologies targeted to specific types of farmers and to specific niches within their farms. The NUANCES framework is not 'just another computer model'! We combine the tools of systems analysis and experimentation, detailed field observations and surveys, incorporate expert knowledge (local knowledge and results of research), generate databases, and apply simulation models to analyse performance of farms, and the impacts of introducing new technologies. We have analysed and described complexity of farming systems, their external drivers and some of the mechanisms that result in (in)efficient use of scarce resources. Studying sites across sub-Saharan Africa has provided insights in the trajectories of change in farming systems in response to population growth, economic conditions and climate variability (cycles of drier and wetter years) and climate change. In regions where human population is dense and land scarce, farm typologies have proven useful to target technologies between farmers of different production objectives and resource endowment (notably in terms of land, labour and capacity for investment). In such regions we could categorise types of fields on the basis of their responsiveness to soil improving technologies along soil fertility gradients, relying on local indicators to differentiate those that may be managed through 'maintenance fertilization' from fields that are highly-responsive to fertilizers and fields that require rehabilitation before yields can improved. Where human population pressure on the land is less intense, farm and field types are harder to discern, without clear patterns. Nutrient cycling through livestock is in principle not efficient for increasing food production due to increased nutrient losses, but is attractive for farmers due to the multiple functions of livestock. We identified trade-offs between income generation, soil conservation and community agreements through optimising concurrent objectives at farm and village levels. These examples show that future analyses must focus at farm and farming system level and not at the level of individual fields to achieve appropriate targeting of technologies -both between locations and between farms at any given location. The approach for integrated assessment described here can be used ex ante to explore the potential of bes...

Toward the Integrated Framework Analysis of Linkages among Agrobiodiversity, Livelihood Diversification, Ecological Systems, and Sustainability amid Global Change

“…These interactions may include unanticipated outcomes. For example, gendered changes have been found to be influential in soil management and the potential of resource-poverty traps [194]. The gendered livelihood changes associated with purportedly beneficial land use, such as conservation agriculture (CA) in African smallholder systems, have been found to undermine nutrient-management goals due to an inequitable shift of labor requirements to women [195].…”

Herders’ opinions about desirable stocking rates and overstocking in the rangelands of northern China

“…In remote pastoral regions, the rangeland is considered as the key primary resource used by households (Xin and Qin 2005;Zhong et al 2008;Giller et al 2011;Yin et al 2011), and plays a vital role in herder decision-making (Xin and Qin 2005;Yin et al 2011). It was evident that the herders who had larger areas of rangelands were more likely to hold that there was no overstocking while the herders with smaller areas of rangelands were more inclined to think that there was already overstocking.…”

Dilemma of nitrogen management for future food security in sub-Saharan Africa – a review

“…Soil acidification, poor organic matter content, deficiencies of various nutrients and reduced microbial activities are among factors affecting crop responses to applied N (Fairhurst 2012;Nezomba et al 2015). Adequate diagnosis of the factors limiting application of integrated soil fertility management (ISFM) is required to optimise AE N (Giller et al 2011) and increase the sustainability of agricultural intensification (Vanlauwe et al 2015).…”