• Energy Research

AbstractApplication of nutrients is an important way to increase crop productivity. In our study area, Tigray, development agents recommend fertilizer application to boost productivity and counteract nutrient depletion. We analysed soil fertility from different perspectives, using responses and nutrient balances on the basis of on‐farm experimentation. Three perspectives, embedded in the People–Planet–Profit framework and with different temporal and spatial scales and ownership, were considered. Taking a farmer perspective, we found no significant differences in response between recommended and current farmer practices. Taking an agronomist perspective, phosphorus seemed to limit productivity. It however also became obvious that closing nutrient balances at field scale to achieve sustainability is difficult. Only by using considerable amounts of manure and at the cost of productivity this can be achieved. From a long‐term environmentalist perspective, the traditional agricultural system seems sustainable in combining mixed farming and relatively low yields. We conclude that depending on the perspective taken, different interventions will be appropriate. All perspectives however indicate that gradually strengthening the existing mixed farming system by using fertilizers, organic manure and legume fallows supports crop productivity while maintaining other aspects of sustainability such as food security and profitability. In line with this, our analysis of different perspectives suggests that in our study area, farmers will only consider transitions with low risk and this specifically should be addressed in proposing pathways of transition. In processes where stakeholders with different perspectives cooperate, it is important to be aware and make use of the possibilities of comparable multi‐perspective analyses. Copyright © 2014 John Wiley & Sons, Ltd.

AbstractEvaluating crop suitability is usually based on traditional land approaches in many countries, using only agro-ecological zoning and soil data. However, land use is also controlled by socio-economic and other biophysical factors. It is actually unknown how coffee suitability is influenced by such socio-economic and biophysical factors. Therefore, here, we studied all known factors that influence coffee production in Rwanda using an inventory of small holder coffee fields, including at least 200 coffee trees. We identified 29 potential factors, including demography, and environmental factors such as climate, soil and topography. These factors were reduced to 17 variables explaining 86 % of the total dataset variability, by factor analysis. The dataset was subsequently stratified into ten agro-ecological zones, yielding regional models that explain regional variability of coffee field density up to 54 %. Regional models show that 60 % of the actual coffee farms are located in suitable locations.

Land use is central to addressing sustainability issues, including biodiversity conservation, climate change, food security, poverty alleviation, and sustainable energy. In this paper, we synthesize knowledge accumulated in land system science, the integrated study of terrestrial social-ecological systems, into 10 hard truths that have strong, general, empirical support. These facts help to explain the challenges of achieving sustainability in land use and thus also point toward solutions. The 10 facts are as follows: 1) Meanings and values of land are socially constructed and contested; 2) land systems exhibit complex behaviors with abrupt, hard-to-predict changes; 3) irreversible changes and path dependence are common features of land systems; 4) some land uses have a small footprint but very large impacts; 5) drivers and impacts of land-use change are globally interconnected and spill over to distant locations; 6) humanity lives on a used planet where all land provides benefits to societies; 7) land-use change usually entails trade-offs between different benefits—"win–wins" are thus rare; 8) land tenure and land-use claims are often unclear, overlapping, and contested; 9) the benefits and burdens from land are unequally distributed; and 10) land users have multiple, sometimes conflicting, ideas of what social and environmental justice entails. The facts have implications for governance, but do not provide fixed answers. Instead they constitute a set of core principles which can guide scientists, policy makers, and practitioners toward meeting sustainability challenges in land use.