In delivering a seminar on Agroforestry Systems and Environmental Quality at the World Agroforestry Centre headquarters on 13 May 2011, Distinguished Professor, PK Nair from the University of Florida, outlined the multiple benefits of agroforestry and the vital role it has to play in addressing current environmental challenges.

“Agroforestry can improve soil productivity, sequester carbon, conserve biodiversity and enhance water quality,” Professor Nair said.

“Agroforestry plays an important role in mitigating soil erosion, thus reducing losses of water, soil material, organic matter and nutrients,” Professor Nair outlined. “It can also reduce deforestation and pressure on woodlands by providing fuelwood grown on farms.”

He gave an example of research in Brazil using butterflies as indicators of biodiversity. The butterflies preferred agroforestry systems over regular agricultural land.

Professor Nair went on to explain how agroforestry has the potential to reduce poverty through increased production of agroforestry products for home consumption and sale. Agroforestry also helps in maintaining cycles such as the nitrogen cycle and carbon cycle, and also increases nitrogen inputs through the use of trees such as Sesbania, Tephrosia, Gliricidia and Faidherbia.

To highlight the current prominence of agroforestry, Professor Nair drew the audience’s attention to an editorial published in the New York Times on 4May 2011 about how soils in Iowa, USA are washing away at a faster rate than anyone could imagine, and how trees will be the solution to addressing the problem. Also, the May issue of the Journal of Environmental Quality contains 10 papers on agroforestry systems and environmental quality.

Focusing much of his talk on Carbon sequestration - Professor Nair’s field of expertise – he explained the importance of capturing Carbon from the atmosphere and storing it securely in long-lived pools in order to reduce the negative effects of carbon emissions in the atmosphere.

“Soils contain more than twice as much Carbon as the atmosphere, therefore carbon naturally stored in soils could provide the short-term bridge to reducing the impacts of increasing carbon emissions until low-carbon and sustainable technologies can be implemented,” Professor Nair explained.

He spoke about how tree-based systems stored more Carbon deeper in the soil compared to treeless systems under similar conditions. In areas of high tree density there is high soil carbon content, especially in the upper 50cm of soil. Where there is sparse tree-density, more Carbon is stored in the soil near a tree than further away from it.

“Traditional systems with large Carbon stock seem to have limited potential for sequestering additional Carbon,” he said.

Nair also mentioned the lack of data on agroforestry species in order to estimate their Carbon storage potential as opposed to forest species. He went on to discuss some of the methodological challenges associated with estimating Carbon storage.

At the end of his presentation Professor Nair challenged staff of the World Agroforestry Centre to be more rigorous in their science He called for deeper evaluation of the why’s and how’s of observed behavior, ensuring the right questions are asked, and not assuming for instance that what applies to Kenya also applies to the Philippines. He mentioned the value of applying powerful analytical and predictive tools while conducting research.

“We must be visible in publications that stand the test of time, are peer reviewed and in high impact journals.”

Professor Nair is currently working on a book title Carbon Sequestration in Agroforestry Systems which will be released in July 2011.

Story by May Kinya (edited by Kate Langford)