- Email: [email protected]
The SRI controversy: a response
Field Crops Research 91 (2005) 357–360 www.elsevier.com/locate/fcr
Discussion
The SRI controversy: a response W.A. Stoopa,*, A.H. Kassamb a
Stoop Consult: R&D for Tropical Agriculture, Akkerweg 13A, 3972 AA Driebergen-R., The Netherlands b CGIAR Science Council, FAO, Rome 00100, Italy Received 2 May 2004; received in revised form 19 July 2004; accepted 29 July 2004
Over the past months there has been an increase in publications ‘‘for’’ and ‘‘against’’ the System of Rice Intensification (SRI). In its March 25th issue NATURE presented a news feature in which the senior editor Chris Surridge provides a well-balanced account of the opposing views expressed by skeptics versus supporters of SRI. The latter are convinced that the system has merits and that a serious research effort is justified to improve our understanding of how it functions and under what conditions (technically, biologically, socially, etc.), it might be profitable. In Field Crops Research 88, 9–10, the skeptics present an outright dismissal of SRI. In their commentary, Sinclair and Cassman warn scientists and peer reviewers against so-called ‘‘agronomic UFOs’’ (unconfirmed field observations) that may be creeping into respectable scientific literature. SRI and ‘‘cold fusion’’ serve as major examples. The latter subject was discussed recently in the New York Times (25th March 2004) and in the New Scientist (20th March 2004) as a subject that continues to be researched by the Massachusetts Institute of Technology (MIT) with funding by the US Department of Energy. World history provides many examples of ideas and theories that were initially rejected by a majority of scientists, * Corresponding author. E-mail address: [email protected] (W.A. Stoop).
but that subsequently, often many years later, still proved to be of major significance to society. The Sinclair and Cassman (2004) commentary was written in support of the recent paper by Sheehy et al. (2004) Field Crops Research 88, 1–8 on a study conducted in China. This study concluded categorically that: ‘‘SRI has no major role in improving rice production’’ and that ‘‘observations of very high yields in Madagascar probably are the consequence of some form of measurement error’’. We feel obliged to react to these two papers for two reasons: the Sheehy et al. research is scientifically and methodologically flawed and therefore the validity of their conclusions concerning SRI need to be questioned; and consequently, the Sinclair and Cassman commentary is inappropriate and unjustified in scientific terms. Initially, in the mid and late 1990s, there was good reason to have reservations about the occasional field reports of exceptionally high yields from SRI obtained in Madagascar. However, the fact that SRI is spreading can no longer be ignored. It has been tested in major rice producing areas of Asia, notably in China, India, Indonesia and the Philippines, and it is being applied
0378-4290/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.fcr.2004.07.023
358
W.A. Stoop, A.H. Kassam / Field Crops Research 91 (2005) 357–360
in one-way-or-another by increasing numbers of farmers. This spread cannot be denied or be explained away by theoretical arguments; or by the suggestion of a ‘‘niche technology’’ suitable only for poor, iron toxic soils (Dobermann, 2003; Sheehy et al., 2004). Neither are the reports of partial (dis-) adoption (Moser and Barrett, 2003 in Madagascar) sufficient reason for discarding the relevance of SRI. Given the relatively complex nature of the SRI technology, as well as the large social and agro-ecological diversity in rice farming, even a substantial degree of dis-adoption is hardly surprising in the adoption process. Against this background it is important to review the origins and the main causes of the controversy about SRI, since it provides a valuable example where agricultural field practitioners (be it farmers, development agents or farm-oriented researchers) do not see eye-to-eye with the agricultural science establishment. What might be the origins and reasons for this controversy? SRI is largely an empirical and experientialderived technology as developed in the mid altitude areas of Madagascar during the 1980s by Father Henri de Laulanie in close collaboration with some smallholder farmers. These efforts have led to a set of practices that differs in fundamental ways from the conventional technologies for irrigated rice: drained instead of continuously flooded fields during the vegetative crop development stage, the use of locally produced compost rather than mineral fertilizers, and the use of very early transplanting of single, widely spaced plants. When professionally implemented this combination of practices has permitted some smallholder farmers to achieve very high yields (Stoop, 2003). The diversity in agro-ecological conditions and of types of farmer who have tried and (sometimes) adopted the SRI package, is however such that it cannot be considered a fixed and/or standardized type of technology. It certainly is very unlike a ‘‘simple’’, single component, technology, such as a chemical plant protection treatment for which the introduction to and adoption by farmers is rather straightforward. What SRI appears to offer to the resource-poor farmer at this stage, is an opportunity to reach a relatively higher yield as well as an increased total factor productivity. An earlier paper by Stoop et al. (2002), often misquoted by SRI critics, was NOT written as a promotion
of SRI. It was instead a critical peer-reviewed effort to identify domains and issues in rice cultivation where ‘‘rice science’’ shows serious knowledge gaps that warrant further research. Not only would such research clarify some of the anomalous features of SRI, but some of its principles could also prove relevant for the production of other crops. Most importantly it would contribute to increased resource use efficiency of land, labour, water and external inputs, and thus reduce the environmental damage that tends to be associated with many forms of modern (rice) farming. This applies in particular to issues like global warming through the release of greenhouse gases like methane, soil degradation/pollution, and the conservation of increasingly scarce irrigation water. Integrated pest management in rice systems in southeast Asia is a similar case, leading to reduced pesticide loading as well as improved actual productivity and returns (Kenmore, 1996). So far hardly any solid research on the various components of SRI and their interactions has been conducted. Most testing of the ‘‘SRI package’’ has been done in small-holder farmers’ fields where soil conditions can differ greatly from intensively used experiment station fields that for many years have received sizeable applications of agricultural chemicals. It is known to take years to regenerate such soils (e.g. for farms switching from conventional to organic/ecological farming) and to re-establish an unsuppressed soil biological environment and equilibrium through liberal applications of organic fertilizers (Bulluck et al., 2002) or compost as is being practiced by successful SRI farmers in Madagascar. Even experienced rice scientists therefore cannot claim to have evaluated SRI convincingly on the basis of a single season of on-station trials. To adequately understand and explain the eco-physiological basis of SRI will be a challenging methodological problem that will not be resolved through a single standardized field experiment such as the one conducted by Sheehy et al. (2004). Different types of experiments and probably several years of basic field research will be required. It also implies that at the present stage neither Sheehy and his co-authors, or for that matter ourselves, can claim to have a full understanding of SRI and the precise basis of the relatively higher yields. The various components of the SRI package create an environment for crop growth, involving chemical,
W.A. Stoop, A.H. Kassam / Field Crops Research 91 (2005) 357–360
physical as well as biological soil factors and processes, that is completely different from that under a conventional irrigated system. In particular, the change from the usual anaerobic, flooded into an aerobic, drained soil environment will have a profound impact on a wide range of soil processes that in turn have been shown to significantly affect plant/crop development in terms of root systems and canopy structure. These features are very different from those presumed optimal for irrigated rice production systems and that have constituted the basis for the crop models employed by Sheehy et al. (2004). Further, their modeling exercise concludes that the highest reported SRI yields are not possible physiologically, a conclusion based exclusively on considerations of photosynthetic activity and efficiency while ignoring the important and complex plant processes that occur in the soil. The latter are known to be crucial to actual crop photosynthesis rates, biomass partitioning and phenological development. To use an analogy, such a modeling exercise focused on some above-ground processes, is like trying to evaluate the human body by doing away with all organs except for the head and brain. The authors seem to want readers to believe that apart from the leaves and solar radiation, the rest of the plant and the below ground environment has nothing to do with the development of a crop and its overall performance over time. While modeling can be a helpful research tool, it has its limitations when the model used does not simulate the complete system, or worse, represents a system different from the one under consideration. When the initial assumptions are incorrect and the information entered incomplete – as appears to be the case by Sheehy et al. (2004) – the outcome of theoretic modeling can become very misleading. Such a result cannot be used to refute empirically recorded superior yields of a practice like SRI whose eco-physiological basis is not yet adequately understood. Recent papers by Dobermann (2003) and by Sheehy et al. (2004) have bypassed what is already known to have happened in farmers’ fields and are trapped in conventional and narrow theoretic thinking in an effort to discredit and thus discard the possible usefulness of SRI. It appears to have escaped the scientists that farming units of small-holder, resourcepoor producers (a major target group for the international fight against hunger and poverty) are
359
obliged to use very different farming strategies. For these farms, maximizing the productivity of available (family) labour is the goal rather than minimizing total labour input, which is the driving force for mechanized farms. These differences in production strategies between resource-poor farms and the larger mechanized farms have large implications for input-use efficiency, and therefore should be of concern to research that is geared towards raising productivity and outputs to reduce poverty and food insecurity. Moreover, the Sheehy et al. field research had serious methodological flaws. The field experimentation conducted in China for a single season and exclusively on experiment stations was of very limited scope and employed water and (mineral) fertilizer regimes inappropriate for SRI. The soil under SRI was kept saturated through daily irrigation during the vegetative stage, thereby creating anaerobic soil conditions. Mineral fertilizer applications were excessively high (180–240 kg N/ha) and along with an incidental application of 1500 kg/ha rape seed cake bypassed the real nature of the problem, which is medium to long term and involves a need to redress the soil’s organic and biological properties. Such problems cannot be assessed and resolved through shortterm experiments. Sheehy et al. (2004) also report that the SRI trials in China lodged, a feature rarely recorded for SRI and an obvious effect of the high N applications, not recommended by any SRI protocol. The experiments had a narrow and hardly a scientific objective, apparently aimed at rapidly refuting SRI on basis of a short-term study. We feel that the experimental design failed to reflect scientific curiosity on the part of the scientists to gain fundamental understanding of how SRI might function. This is also true of the theoretic model that was used to support the outcome of the data from the field experiments, as elaborated above. A most interesting aspect of the SRI debate is that it presents a clear example of a long term controversy based on two contrasting ‘‘research philosophies’’ (including its links to development): an integral versus a reductionist view. The first is relatively ‘‘open’’ to the surprises of incompletely or unexplored domains and the opportunities created by essentially incomplete knowledge; the second is much more dogmatic and clings to established knowledge and principles, while missing out on livelihood aspects. The convic-
360
W.A. Stoop, A.H. Kassam / Field Crops Research 91 (2005) 357–360
tion that we need both – yet properly balanced – provides a major reason for engaging in this debate. Without such balance, research may become reduced to a costly, number-crunching ‘‘robotic’’ exercise. Conspicuously absent in the Sheehy et al. (2004) paper and the Sinclair and Cassman (2004) commentary was the element of scientific curiosity to discover and understand what makes SRI work, under what conditions (technically, biologically, socially, etc.) and why it might suit certain groups of farmers. Our concerns therefore are very serious. Not only do we conclude that the Sheehy et al. research is flawed and far from conclusive, but also that it is surprising – for whatever reason – it receives such strong backing from Sinclair and Cassman. Implicitly the latter seek to undermine the credibility of any scientist who might be interested to explore SRI in more detail. As indicated above such research could, however serve highly relevant objectives including long term social and environmental ones, apart from its crucial and fundamental inputs into ‘‘problembased science’’. Trying to block or discourage such research by using emotive analogies like UFOs is therefore highly deplorable. Sinclair and Cassman (2004) express concern about the current scarcity of funding for agricultural research and therefore argue for strict priority-setting procedures. However, research on SRI does not necessarily require huge amounts of funds that would ‘‘financially compete’’ with other research or with development efforts. Therefore one might question ‘‘whose priorities’’ Sinclair and Cassman are so concerned about? Based
on this analysis of the SRI controversy, one fears that perhaps the short-term interests of some (rice) scientists and/or the credibility of certain (research) institutions may be the true overriding concern why some feel compelled to discredit SRI.
References Bulluck III, L.R., Brosius, M., Evanylo, G.K., Ristaino, J.B., 2002. Organic and synthetic fertility amendments influence soil microbial, physical and chemical properties on organic and conventional farms. Appl. Soil Ecol. 19, 147–160. Dobermann, A., 2003. A critical assessment of the system of rice intensification (SRI). Agric. Syst. 79, 261–281. Kenmore, P.E., 1996. Integrated pest management in rice. In: Persley, G.J. (Ed.), Biotechnology and Integrated Pest Management. CAB International, Wallingford, UK, pp. 76–97. Moser, C.M., Barrett, C.B., 2003. The disappointing adoption dynamics of a yield-increasing, low external-input technology: the case of SRI in Madagascar. Agric. Syst. 76, 1085–1100. Sheehy, J.E., Peng, S., Dobermann, A., Mitchell, P.L., Ferrer, A., Yang, J., Zou, Y., Zhong, X., Huang, J., 2004. Fantastic yields in the system of rice intensification: fact or fallacy? Field Crops Res. 88, 1–8. Sinclair, T.R., Cassman, K.G., 2004. Agronomic UFOs? Field Crops Res. 88, 9–10. Stoop, W.A., 2003. The system of rice intensification (SRI) from Madagascar; myth or missed opportunity? Report on a study visit to the ‘‘Hauts Plateaux’’ region of Madagascar. STOOP Consult, Driebergen-R., The Netherlands, March 3–15, 2003, 17 pp. Stoop, W.A., Uphoff, N., Kassam, A., 2002. A review of agricultural research issues raised by the system of rice intensification (SRI) from Madagascar: opportunities for improving farming systems for resource-poor farmers. Agric. Syst. 71, 249–274.
Discussion
The SRI controversy: a response W.A. Stoopa,*, A.H. Kassamb a
Stoop Consult: R&D for Tropical Agriculture, Akkerweg 13A, 3972 AA Driebergen-R., The Netherlands b CGIAR Science Council, FAO, Rome 00100, Italy Received 2 May 2004; received in revised form 19 July 2004; accepted 29 July 2004
Over the past months there has been an increase in publications ‘‘for’’ and ‘‘against’’ the System of Rice Intensification (SRI). In its March 25th issue NATURE presented a news feature in which the senior editor Chris Surridge provides a well-balanced account of the opposing views expressed by skeptics versus supporters of SRI. The latter are convinced that the system has merits and that a serious research effort is justified to improve our understanding of how it functions and under what conditions (technically, biologically, socially, etc.), it might be profitable. In Field Crops Research 88, 9–10, the skeptics present an outright dismissal of SRI. In their commentary, Sinclair and Cassman warn scientists and peer reviewers against so-called ‘‘agronomic UFOs’’ (unconfirmed field observations) that may be creeping into respectable scientific literature. SRI and ‘‘cold fusion’’ serve as major examples. The latter subject was discussed recently in the New York Times (25th March 2004) and in the New Scientist (20th March 2004) as a subject that continues to be researched by the Massachusetts Institute of Technology (MIT) with funding by the US Department of Energy. World history provides many examples of ideas and theories that were initially rejected by a majority of scientists, * Corresponding author. E-mail address: [email protected] (W.A. Stoop).
but that subsequently, often many years later, still proved to be of major significance to society. The Sinclair and Cassman (2004) commentary was written in support of the recent paper by Sheehy et al. (2004) Field Crops Research 88, 1–8 on a study conducted in China. This study concluded categorically that: ‘‘SRI has no major role in improving rice production’’ and that ‘‘observations of very high yields in Madagascar probably are the consequence of some form of measurement error’’. We feel obliged to react to these two papers for two reasons: the Sheehy et al. research is scientifically and methodologically flawed and therefore the validity of their conclusions concerning SRI need to be questioned; and consequently, the Sinclair and Cassman commentary is inappropriate and unjustified in scientific terms. Initially, in the mid and late 1990s, there was good reason to have reservations about the occasional field reports of exceptionally high yields from SRI obtained in Madagascar. However, the fact that SRI is spreading can no longer be ignored. It has been tested in major rice producing areas of Asia, notably in China, India, Indonesia and the Philippines, and it is being applied
0378-4290/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.fcr.2004.07.023
358
W.A. Stoop, A.H. Kassam / Field Crops Research 91 (2005) 357–360
in one-way-or-another by increasing numbers of farmers. This spread cannot be denied or be explained away by theoretical arguments; or by the suggestion of a ‘‘niche technology’’ suitable only for poor, iron toxic soils (Dobermann, 2003; Sheehy et al., 2004). Neither are the reports of partial (dis-) adoption (Moser and Barrett, 2003 in Madagascar) sufficient reason for discarding the relevance of SRI. Given the relatively complex nature of the SRI technology, as well as the large social and agro-ecological diversity in rice farming, even a substantial degree of dis-adoption is hardly surprising in the adoption process. Against this background it is important to review the origins and the main causes of the controversy about SRI, since it provides a valuable example where agricultural field practitioners (be it farmers, development agents or farm-oriented researchers) do not see eye-to-eye with the agricultural science establishment. What might be the origins and reasons for this controversy? SRI is largely an empirical and experientialderived technology as developed in the mid altitude areas of Madagascar during the 1980s by Father Henri de Laulanie in close collaboration with some smallholder farmers. These efforts have led to a set of practices that differs in fundamental ways from the conventional technologies for irrigated rice: drained instead of continuously flooded fields during the vegetative crop development stage, the use of locally produced compost rather than mineral fertilizers, and the use of very early transplanting of single, widely spaced plants. When professionally implemented this combination of practices has permitted some smallholder farmers to achieve very high yields (Stoop, 2003). The diversity in agro-ecological conditions and of types of farmer who have tried and (sometimes) adopted the SRI package, is however such that it cannot be considered a fixed and/or standardized type of technology. It certainly is very unlike a ‘‘simple’’, single component, technology, such as a chemical plant protection treatment for which the introduction to and adoption by farmers is rather straightforward. What SRI appears to offer to the resource-poor farmer at this stage, is an opportunity to reach a relatively higher yield as well as an increased total factor productivity. An earlier paper by Stoop et al. (2002), often misquoted by SRI critics, was NOT written as a promotion
of SRI. It was instead a critical peer-reviewed effort to identify domains and issues in rice cultivation where ‘‘rice science’’ shows serious knowledge gaps that warrant further research. Not only would such research clarify some of the anomalous features of SRI, but some of its principles could also prove relevant for the production of other crops. Most importantly it would contribute to increased resource use efficiency of land, labour, water and external inputs, and thus reduce the environmental damage that tends to be associated with many forms of modern (rice) farming. This applies in particular to issues like global warming through the release of greenhouse gases like methane, soil degradation/pollution, and the conservation of increasingly scarce irrigation water. Integrated pest management in rice systems in southeast Asia is a similar case, leading to reduced pesticide loading as well as improved actual productivity and returns (Kenmore, 1996). So far hardly any solid research on the various components of SRI and their interactions has been conducted. Most testing of the ‘‘SRI package’’ has been done in small-holder farmers’ fields where soil conditions can differ greatly from intensively used experiment station fields that for many years have received sizeable applications of agricultural chemicals. It is known to take years to regenerate such soils (e.g. for farms switching from conventional to organic/ecological farming) and to re-establish an unsuppressed soil biological environment and equilibrium through liberal applications of organic fertilizers (Bulluck et al., 2002) or compost as is being practiced by successful SRI farmers in Madagascar. Even experienced rice scientists therefore cannot claim to have evaluated SRI convincingly on the basis of a single season of on-station trials. To adequately understand and explain the eco-physiological basis of SRI will be a challenging methodological problem that will not be resolved through a single standardized field experiment such as the one conducted by Sheehy et al. (2004). Different types of experiments and probably several years of basic field research will be required. It also implies that at the present stage neither Sheehy and his co-authors, or for that matter ourselves, can claim to have a full understanding of SRI and the precise basis of the relatively higher yields. The various components of the SRI package create an environment for crop growth, involving chemical,
W.A. Stoop, A.H. Kassam / Field Crops Research 91 (2005) 357–360
physical as well as biological soil factors and processes, that is completely different from that under a conventional irrigated system. In particular, the change from the usual anaerobic, flooded into an aerobic, drained soil environment will have a profound impact on a wide range of soil processes that in turn have been shown to significantly affect plant/crop development in terms of root systems and canopy structure. These features are very different from those presumed optimal for irrigated rice production systems and that have constituted the basis for the crop models employed by Sheehy et al. (2004). Further, their modeling exercise concludes that the highest reported SRI yields are not possible physiologically, a conclusion based exclusively on considerations of photosynthetic activity and efficiency while ignoring the important and complex plant processes that occur in the soil. The latter are known to be crucial to actual crop photosynthesis rates, biomass partitioning and phenological development. To use an analogy, such a modeling exercise focused on some above-ground processes, is like trying to evaluate the human body by doing away with all organs except for the head and brain. The authors seem to want readers to believe that apart from the leaves and solar radiation, the rest of the plant and the below ground environment has nothing to do with the development of a crop and its overall performance over time. While modeling can be a helpful research tool, it has its limitations when the model used does not simulate the complete system, or worse, represents a system different from the one under consideration. When the initial assumptions are incorrect and the information entered incomplete – as appears to be the case by Sheehy et al. (2004) – the outcome of theoretic modeling can become very misleading. Such a result cannot be used to refute empirically recorded superior yields of a practice like SRI whose eco-physiological basis is not yet adequately understood. Recent papers by Dobermann (2003) and by Sheehy et al. (2004) have bypassed what is already known to have happened in farmers’ fields and are trapped in conventional and narrow theoretic thinking in an effort to discredit and thus discard the possible usefulness of SRI. It appears to have escaped the scientists that farming units of small-holder, resourcepoor producers (a major target group for the international fight against hunger and poverty) are
359
obliged to use very different farming strategies. For these farms, maximizing the productivity of available (family) labour is the goal rather than minimizing total labour input, which is the driving force for mechanized farms. These differences in production strategies between resource-poor farms and the larger mechanized farms have large implications for input-use efficiency, and therefore should be of concern to research that is geared towards raising productivity and outputs to reduce poverty and food insecurity. Moreover, the Sheehy et al. field research had serious methodological flaws. The field experimentation conducted in China for a single season and exclusively on experiment stations was of very limited scope and employed water and (mineral) fertilizer regimes inappropriate for SRI. The soil under SRI was kept saturated through daily irrigation during the vegetative stage, thereby creating anaerobic soil conditions. Mineral fertilizer applications were excessively high (180–240 kg N/ha) and along with an incidental application of 1500 kg/ha rape seed cake bypassed the real nature of the problem, which is medium to long term and involves a need to redress the soil’s organic and biological properties. Such problems cannot be assessed and resolved through shortterm experiments. Sheehy et al. (2004) also report that the SRI trials in China lodged, a feature rarely recorded for SRI and an obvious effect of the high N applications, not recommended by any SRI protocol. The experiments had a narrow and hardly a scientific objective, apparently aimed at rapidly refuting SRI on basis of a short-term study. We feel that the experimental design failed to reflect scientific curiosity on the part of the scientists to gain fundamental understanding of how SRI might function. This is also true of the theoretic model that was used to support the outcome of the data from the field experiments, as elaborated above. A most interesting aspect of the SRI debate is that it presents a clear example of a long term controversy based on two contrasting ‘‘research philosophies’’ (including its links to development): an integral versus a reductionist view. The first is relatively ‘‘open’’ to the surprises of incompletely or unexplored domains and the opportunities created by essentially incomplete knowledge; the second is much more dogmatic and clings to established knowledge and principles, while missing out on livelihood aspects. The convic-
360
W.A. Stoop, A.H. Kassam / Field Crops Research 91 (2005) 357–360
tion that we need both – yet properly balanced – provides a major reason for engaging in this debate. Without such balance, research may become reduced to a costly, number-crunching ‘‘robotic’’ exercise. Conspicuously absent in the Sheehy et al. (2004) paper and the Sinclair and Cassman (2004) commentary was the element of scientific curiosity to discover and understand what makes SRI work, under what conditions (technically, biologically, socially, etc.) and why it might suit certain groups of farmers. Our concerns therefore are very serious. Not only do we conclude that the Sheehy et al. research is flawed and far from conclusive, but also that it is surprising – for whatever reason – it receives such strong backing from Sinclair and Cassman. Implicitly the latter seek to undermine the credibility of any scientist who might be interested to explore SRI in more detail. As indicated above such research could, however serve highly relevant objectives including long term social and environmental ones, apart from its crucial and fundamental inputs into ‘‘problembased science’’. Trying to block or discourage such research by using emotive analogies like UFOs is therefore highly deplorable. Sinclair and Cassman (2004) express concern about the current scarcity of funding for agricultural research and therefore argue for strict priority-setting procedures. However, research on SRI does not necessarily require huge amounts of funds that would ‘‘financially compete’’ with other research or with development efforts. Therefore one might question ‘‘whose priorities’’ Sinclair and Cassman are so concerned about? Based
on this analysis of the SRI controversy, one fears that perhaps the short-term interests of some (rice) scientists and/or the credibility of certain (research) institutions may be the true overriding concern why some feel compelled to discredit SRI.
References Bulluck III, L.R., Brosius, M., Evanylo, G.K., Ristaino, J.B., 2002. Organic and synthetic fertility amendments influence soil microbial, physical and chemical properties on organic and conventional farms. Appl. Soil Ecol. 19, 147–160. Dobermann, A., 2003. A critical assessment of the system of rice intensification (SRI). Agric. Syst. 79, 261–281. Kenmore, P.E., 1996. Integrated pest management in rice. In: Persley, G.J. (Ed.), Biotechnology and Integrated Pest Management. CAB International, Wallingford, UK, pp. 76–97. Moser, C.M., Barrett, C.B., 2003. The disappointing adoption dynamics of a yield-increasing, low external-input technology: the case of SRI in Madagascar. Agric. Syst. 76, 1085–1100. Sheehy, J.E., Peng, S., Dobermann, A., Mitchell, P.L., Ferrer, A., Yang, J., Zou, Y., Zhong, X., Huang, J., 2004. Fantastic yields in the system of rice intensification: fact or fallacy? Field Crops Res. 88, 1–8. Sinclair, T.R., Cassman, K.G., 2004. Agronomic UFOs? Field Crops Res. 88, 9–10. Stoop, W.A., 2003. The system of rice intensification (SRI) from Madagascar; myth or missed opportunity? Report on a study visit to the ‘‘Hauts Plateaux’’ region of Madagascar. STOOP Consult, Driebergen-R., The Netherlands, March 3–15, 2003, 17 pp. Stoop, W.A., Uphoff, N., Kassam, A., 2002. A review of agricultural research issues raised by the system of rice intensification (SRI) from Madagascar: opportunities for improving farming systems for resource-poor farmers. Agric. Syst. 71, 249–274.