Description:    Agroforestry systems are widely practiced in tropical forests to recover degraded and deforested areas and also to balance the global carbon budget. However, our understanding of difference in soil respiration rates between agroforestry and natural forest systems is very limited. This study compared the seasonal variations in soil respiration rates in relation to fine root biomass, microbial biomass, and soil organic carbon between a secondary forest and two agroforestry systems dominated by Gmelina arborea and Dipterocarps in the Philippines during the dry and the wet seasons. The secondary forest had significantly higher ( p  〈 0.05) soil respiration rate, fine root biomass and soil organic matter than the agroforestry systems in the dry season. However, in the wet season, soil respiration and soil organic matter in the G. arborea dominated agroforestry system were as high as in the secondary forest. Whereas soil respiration was generally higher in the wet than in the dry season, there were no differences in fine root biomass, microbial biomass and soil organic matter between the two seasons. Soil respiration rate correlated positively and significantly with fine root biomass, microbial biomass, and soil organic C in all three sites. The results of this study indicate, to some degree, that different land use management practices have different effects on fine root biomass, microbial biomass and soil organic C which may affect soil respiration as well. Therefore, when introducing agroforestry system, a proper choice of species and management techniques which are similar to natural forest is recommended. Content Type Journal Article Pages 1-9 DOI 10.1007/s10457-012-9530-8 Authors Kikang Bae, Department of Forest and Natural Resources Management, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210, USA Don Koo Lee, Department of Forest Science, Seoul National University, Seoul, 151-742 Korea Timothy J. Fahey, Department of Natural Resources, Cornell University, Ithaca, NY 14853, USA Soo Young Woo, Department of Environmental Horticulture, University of Seoul, Seoul, 130-743 Republic of Korea Amos K. Quaye, Department of Forest and Natural Resources Management, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210, USA Yong-Kwon Lee, Korea Forest Service, Government Complex-Daejeon, Bldg 1, 189 Cheongsa-ro, Seo-gu, Daejeon, 302-701 Republic of Korea Journal Agroforestry Systems Online ISSN 1572-9680 Print ISSN 0167-4366

Description:    Participatory research methods have helped scientists to understand how farmers experiment and to seek partnerships with farmers in developing technologies with enhanced relevance and adoption. This paper reports on the development of a participatory methodology to systematize long-term experimentation with agroforestry systems carried out in a hotspot of biodiversity by non-governmental organizations and local farmers. A methodological guide for systematization and techniques used for Participatory Rural Appraisal formed the basis of our work. We propose an analytical framework that recognizes systems of reflexive and learning interactions, in order to make the learned lessons explicit. At the process level, the main lessons and recommendations are as follows. It is important to establish partnerships to conduct innovative and complex experimentation with agroforest. Participatory systematization allows us to improve the methodological aspects of design, implementation and management of on-farm participatory experimentation. It also serves to synthesize the main findings and to extract lessons from agroforestry systems experiments. It fosters the technical improvement of agroforestry systems. It creates possibilities for reflection on agroforestry systems by farmers, extensionists and researchers, as well as their learning with respect to management of such systems. The findings are placed in the context of current theory on participatory experimentation in agriculture. Extractive and interactive approaches help to produce rich insights of mutual interest through collaboration by identifying local, regional and global convergences, complementarities, and conflicts of interest; which affect the advance of new eco-friendly technologies, to both improve the livelihoods and to reverse biodiversity loss and environmental degradation. Content Type Journal Article Pages 1-16 DOI 10.1007/s10457-012-9498-4 Authors Helton Nonato de Souza, Department of Soil Quality, Wageningen University, Wageningen, The Netherlands Irene Maria Cardoso, Soil Science Department, Federal University of Viçosa, Viçosa, Brazil Eduardo de Sá Mendonça, Plant Production Department, Federal University of Espírito Santo, Alegre, ES 29500-000, Brazil Anôr Fiorini Carvalho, Soil Science Department, Federal University of Viçosa, Viçosa, Brazil Gustavo Bediaga de Oliveira, Centre of Alternative Technologies of Zona da Mata (CTA-ZM), Sitio Alfa Violeira, Zona Rural, Caixa Postal 128, Cep, Viçosa, MG 36570 000, Brazil Davi Feital Gjorup, Centre of Alternative Technologies of Zona da Mata (CTA-ZM), Sitio Alfa Violeira, Zona Rural, Caixa Postal 128, Cep, Viçosa, MG 36570 000, Brazil Verônica Rocha Bonfim, Centre of Alternative Technologies of Zona da Mata (CTA-ZM), Sitio Alfa Violeira, Zona Rural, Caixa Postal 128, Cep, Viçosa, MG 36570 000, Brazil Journal Agroforestry Systems Online ISSN 1572-9680 Print ISSN 0167-4366

Description: Agriculture significantly contributes to global greenhouse gas (GHG) emissions and there is a need to develop effective mitigation strategies. The efficacy of methods to reduce GHG fluxes from agricultural soils can be affected by a range of interacting management and environmental factors. Uniquely, we used the Taguchi experimental design methodology to rank the relative importance of six factors known to affect the emission of GHG from soil: nitrate (NO 3 − ) addition, carbon quality (labile and non-labile C), soil temperature, water-filled pore space (WFPS) and extent of soil compaction. Grassland soil was incubated in jars where selected factors, considered at two or three amounts within the experimental range, were combined in an orthogonal array to determine the importance and interactions between factors with a L 16 design, comprising 16 experimental units. Within this L 16 design, 216 combinations of the full factorial experimental design were represented. Headspace nitrous oxide (N 2 O), methane (CH 4 ) and carbon dioxide (CO 2 ) concentrations were measured and used to calculate fluxes. Results found for the relative influence of factors (WFPS and NO 3 − addition were the main factors affecting N 2 O fluxes, whilst glucose, NO 3 − and soil temperature were the main factors affecting CO 2 and CH 4 fluxes) were consistent with those already well documented. Interactions between factors were also studied and results showed that factors with little individual influence became more influential in combination. The proposed methodology offers new possibilities for GHG researchers to study interactions between influential factors and address the optimized sets of conditions to reduce GHG emissions in agro-ecosystems, while reducing the number of experimental units required compared with conventional experimental procedures that adjust one variable at a time.