By modifying the microclimate for the benefit of understorey crops, agroforestry would also seem to be a way of adapting agriculture in response to climate change. Lastly, by virtue of the wider range of crops they include, agroforestry systems can also provide solutions to crises. In September, 130 researchers from 25 countries looked into this issue at the 2nd International Symposium on Multistrata Agroforestry Systems with Perennial Crops, held in Costa Rica*.
The aim was to find ways of promoting such systems, by assessing the research results obtained in the eight years since the first symposium. The participants also set out to propose appropriate mechanisms for ensuring that farmers who make the effort to adopt such ecofriendly production systems reap some reward.
A role to play in a rapidly changing environment
Multistrata agroforestry systems associating crops with trees, with the crops developing in the shade provided by the trees, have existed for some considerable time in many tropical countries. For instance, perennial crops such as coffee or cocoa can be grown in the shade of fruit and/or forest trees, making up at least three strata of vegetation. However, with the advent of intensive agriculture, some 40-50 years ago, farmers often abandoned the practice in favour of monocultures, which generate profits sooner. However, the prospects for this type of intensive agriculture, which is reliant on massive external inputs, are now limited, due to its serious adverse effects on the environment and to various economic constraints. Furthermore, times are changing, as is the climate, and public awareness is increasing. Consumers are increasingly buying "ethically", "ecologically", "organically" or "fairly", and are thus more likely to pay more to be sure of buying ecofriendly, socially responsible products. This is where the products of agroforestry systems come in.
Lower production counteracted by the environmental services rendered
However, the main obstacle to the large-scale adoption of such systems has been maintaining farmers' incomes. The environmental services rendered by agroforestry systems are now recognized, but shaded cropping can produce lower yields than intensive monocultures. This is often the case, for instance, with arabica coffee grown at more than 1000 m above sea level. Given the importance of this constraint, researchers are insisting on the need to maintain incomes. Two main ways of achieving this have been suggested. The first consists in paying farmers for the environmental services rendered by their crops. This could be done through ecolabels such as "organic" or "Rainforest Alliance", which already exist on the market, through a national system of payment for carbon sequestration or, more locally, through direct payment from users of services, for instance hydroelectric dam operators paying farmers to protect soils against erosion. The other possibility is to diversify the crops grown and domesticate woody species, in the aim of making such operations profitable by creating or improving wood product marketing channels. For instance, timber serves to improve incomes among coffee producers when coffee prices fall in Central America. Likewise, palm wine plays a major role in ensuring the sustainability of cocoa-growing systems in the forests of Ivory Coast.
Certification: a strategy to be integrated into development programmes
At the end of the symposium, it was also recommended that the issue of biodiversity be associated with that of system productivity in studies and models. In effect, while it has been clearly established that agroforestry systems conserve and/or increase flora and fauna biodiversity, the impact of that biodiversity on the economic sustainability of such systems has yet to be determined. The beneficial effects of these agroforestry systems on a landscape scale, for instance their role in the connectivity between protected areas, also need to be explained more clearly. As regards existing biophysical results, compiling them in meta-databases would make it possible to organize the available information better, communicate about methodologies and results, apply those results more effectively, and identify research requirements. A modelling approach, perhaps coupled with an analysis of these metabases, would help to resolve the most crucial issues, such as the relations between crop yields and shading, or the impact of climate change on the functions of and the services rendered by the ecosystem. Lastly, certification is a strategy that could be integrated into the very heart of development programmes. However, this would mean improving the scientific bases of the biophysical and social criteria and indicators applied when attributing ecolabels.
* The symposium was organized by the Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), CIRAD, the International Center for Research in Agroforestry (ICRAF) and the University of Wales. It followed on from an initial symposium held in February 1999, also at CATIE, in Turrialba, Costa Rica.
Helen Burford | alfa
New gene for atrazine resistance identified in waterhemp
24.02.2017 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
Researchers discover a new link to fight billion-dollar threat to soybean production
14.02.2017 | University of Missouri-Columbia
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
24.02.2017 | Earth Sciences
24.02.2017 | Agricultural and Forestry Science
24.02.2017 | Life Sciences