The Experts below are selected from a list of 67863 Experts worldwide ranked by ideXlab platform
David Makowski - One of the best experts on this subject based on the ideXlab platform.
-
Yield variability in organic versus conventional systems : a meta-analysis for horticultural systems. PS-8.1-02
2018Co-Authors: Eric Malézieux, Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, David MakowskiAbstract:Organic agriculture has the potential to reduce the impacts of agriculture on humans and ecosystems but its productivity compared to conventional agriculture remains a contentious issue. Previous meta-analyses have shown that yields in organic systems are 10 to 25 % lower compared with conventional systems. However, those metaanalysis estimated the average yield gap of organic versus conventional farming systems but did not consider yields spatio-temporal variability. Although it is a major concern for farmers and food chains, only few studies analysed the relative variability of organic systems compared to conventional ones. Two contrary hypotheses exist in the literature. On the one hand, because of its reliance on biological and ecological processes, organic production can be assumed to be more vulnerable to pests and diseases outbreaks. On the other hand, organic farming systems are known to have a greater structural diversity and to optimize nutrient cycling and biological pest regulation, which may hence induce a higher resilience of the system and yields. Here we focus on Horticulture crops (fruits and vegetables) and make progress by estimating the variability of organic to conventional yield ratio across experiments and across years for a series of horticultural species from a meta-analysis of published field experiments. We define Horticulture as production systems based on vegetables and/or fruit production, both in fields, market gardens or orchards. We analyse a dataset including the results of 52 papers reporting yield data for 37 horticultural species in 17 countries. We find that yields in organic Horticulture are on average 10 to 32 % lower than those in conventional Horticulture. The variance of yields was not significantly different between organic and conventional systems, hence we find no evidence of a larger inter annual variability in organic versus conventional Horticulture. However, the coefficient of variation is significantly higher for organic yields vs. conventional ones reflecting the yield gap between these systems. We find no significant effect on yield ratios of type of crop, type of product nor type of climate. However, data on tropical zones were scarce. As a conclusion, despite lower yields, productivity of organic systems is not more instable that productivity of conventional ones, an important result for farmers and future development of organic Horticulture.
-
Lower average yields but similar yield variability in organic versus conventional Horticulture. A meta-analysis
Agronomy for Sustainable Development, 2017Co-Authors: Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, Eric Malézieux, David MakowskiAbstract:Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on Horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic Horticulture are indeed on average 10 to 32% lower than those in conventional Horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic Horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic Horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional Horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.
-
Lower average yields but similar yield variability in organic versus conventional Horticulture
Agronomy for Sustainable Development, 2017Co-Authors: Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, Eric Malézieux, David MakowskiAbstract:Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on Horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic Horticulture are indeed on average 10 to 32% lower than those in conventional Horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic Horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic Horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional Horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.
Claire Lesur-dumoulin - One of the best experts on this subject based on the ideXlab platform.
-
Yield variability in organic versus conventional systems : a meta-analysis for horticultural systems. PS-8.1-02
2018Co-Authors: Eric Malézieux, Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, David MakowskiAbstract:Organic agriculture has the potential to reduce the impacts of agriculture on humans and ecosystems but its productivity compared to conventional agriculture remains a contentious issue. Previous meta-analyses have shown that yields in organic systems are 10 to 25 % lower compared with conventional systems. However, those metaanalysis estimated the average yield gap of organic versus conventional farming systems but did not consider yields spatio-temporal variability. Although it is a major concern for farmers and food chains, only few studies analysed the relative variability of organic systems compared to conventional ones. Two contrary hypotheses exist in the literature. On the one hand, because of its reliance on biological and ecological processes, organic production can be assumed to be more vulnerable to pests and diseases outbreaks. On the other hand, organic farming systems are known to have a greater structural diversity and to optimize nutrient cycling and biological pest regulation, which may hence induce a higher resilience of the system and yields. Here we focus on Horticulture crops (fruits and vegetables) and make progress by estimating the variability of organic to conventional yield ratio across experiments and across years for a series of horticultural species from a meta-analysis of published field experiments. We define Horticulture as production systems based on vegetables and/or fruit production, both in fields, market gardens or orchards. We analyse a dataset including the results of 52 papers reporting yield data for 37 horticultural species in 17 countries. We find that yields in organic Horticulture are on average 10 to 32 % lower than those in conventional Horticulture. The variance of yields was not significantly different between organic and conventional systems, hence we find no evidence of a larger inter annual variability in organic versus conventional Horticulture. However, the coefficient of variation is significantly higher for organic yields vs. conventional ones reflecting the yield gap between these systems. We find no significant effect on yield ratios of type of crop, type of product nor type of climate. However, data on tropical zones were scarce. As a conclusion, despite lower yields, productivity of organic systems is not more instable that productivity of conventional ones, an important result for farmers and future development of organic Horticulture.
-
Lower average yields but similar yield variability in organic versus conventional Horticulture. A meta-analysis
Agronomy for Sustainable Development, 2017Co-Authors: Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, Eric Malézieux, David MakowskiAbstract:Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on Horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic Horticulture are indeed on average 10 to 32% lower than those in conventional Horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic Horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic Horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional Horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.
-
Lower average yields but similar yield variability in organic versus conventional Horticulture
Agronomy for Sustainable Development, 2017Co-Authors: Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, Eric Malézieux, David MakowskiAbstract:Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on Horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic Horticulture are indeed on average 10 to 32% lower than those in conventional Horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic Horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic Horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional Horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.
Eric Malézieux - One of the best experts on this subject based on the ideXlab platform.
-
Yield variability in organic versus conventional systems : a meta-analysis for horticultural systems. PS-8.1-02
2018Co-Authors: Eric Malézieux, Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, David MakowskiAbstract:Organic agriculture has the potential to reduce the impacts of agriculture on humans and ecosystems but its productivity compared to conventional agriculture remains a contentious issue. Previous meta-analyses have shown that yields in organic systems are 10 to 25 % lower compared with conventional systems. However, those metaanalysis estimated the average yield gap of organic versus conventional farming systems but did not consider yields spatio-temporal variability. Although it is a major concern for farmers and food chains, only few studies analysed the relative variability of organic systems compared to conventional ones. Two contrary hypotheses exist in the literature. On the one hand, because of its reliance on biological and ecological processes, organic production can be assumed to be more vulnerable to pests and diseases outbreaks. On the other hand, organic farming systems are known to have a greater structural diversity and to optimize nutrient cycling and biological pest regulation, which may hence induce a higher resilience of the system and yields. Here we focus on Horticulture crops (fruits and vegetables) and make progress by estimating the variability of organic to conventional yield ratio across experiments and across years for a series of horticultural species from a meta-analysis of published field experiments. We define Horticulture as production systems based on vegetables and/or fruit production, both in fields, market gardens or orchards. We analyse a dataset including the results of 52 papers reporting yield data for 37 horticultural species in 17 countries. We find that yields in organic Horticulture are on average 10 to 32 % lower than those in conventional Horticulture. The variance of yields was not significantly different between organic and conventional systems, hence we find no evidence of a larger inter annual variability in organic versus conventional Horticulture. However, the coefficient of variation is significantly higher for organic yields vs. conventional ones reflecting the yield gap between these systems. We find no significant effect on yield ratios of type of crop, type of product nor type of climate. However, data on tropical zones were scarce. As a conclusion, despite lower yields, productivity of organic systems is not more instable that productivity of conventional ones, an important result for farmers and future development of organic Horticulture.
-
Lower average yields but similar yield variability in organic versus conventional Horticulture. A meta-analysis
Agronomy for Sustainable Development, 2017Co-Authors: Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, Eric Malézieux, David MakowskiAbstract:Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on Horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic Horticulture are indeed on average 10 to 32% lower than those in conventional Horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic Horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic Horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional Horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.
-
Lower average yields but similar yield variability in organic versus conventional Horticulture
Agronomy for Sustainable Development, 2017Co-Authors: Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, Eric Malézieux, David MakowskiAbstract:Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on Horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic Horticulture are indeed on average 10 to 32% lower than those in conventional Horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic Horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic Horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional Horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.
Christian Langlais - One of the best experts on this subject based on the ideXlab platform.
-
Yield variability in organic versus conventional systems : a meta-analysis for horticultural systems. PS-8.1-02
2018Co-Authors: Eric Malézieux, Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, David MakowskiAbstract:Organic agriculture has the potential to reduce the impacts of agriculture on humans and ecosystems but its productivity compared to conventional agriculture remains a contentious issue. Previous meta-analyses have shown that yields in organic systems are 10 to 25 % lower compared with conventional systems. However, those metaanalysis estimated the average yield gap of organic versus conventional farming systems but did not consider yields spatio-temporal variability. Although it is a major concern for farmers and food chains, only few studies analysed the relative variability of organic systems compared to conventional ones. Two contrary hypotheses exist in the literature. On the one hand, because of its reliance on biological and ecological processes, organic production can be assumed to be more vulnerable to pests and diseases outbreaks. On the other hand, organic farming systems are known to have a greater structural diversity and to optimize nutrient cycling and biological pest regulation, which may hence induce a higher resilience of the system and yields. Here we focus on Horticulture crops (fruits and vegetables) and make progress by estimating the variability of organic to conventional yield ratio across experiments and across years for a series of horticultural species from a meta-analysis of published field experiments. We define Horticulture as production systems based on vegetables and/or fruit production, both in fields, market gardens or orchards. We analyse a dataset including the results of 52 papers reporting yield data for 37 horticultural species in 17 countries. We find that yields in organic Horticulture are on average 10 to 32 % lower than those in conventional Horticulture. The variance of yields was not significantly different between organic and conventional systems, hence we find no evidence of a larger inter annual variability in organic versus conventional Horticulture. However, the coefficient of variation is significantly higher for organic yields vs. conventional ones reflecting the yield gap between these systems. We find no significant effect on yield ratios of type of crop, type of product nor type of climate. However, data on tropical zones were scarce. As a conclusion, despite lower yields, productivity of organic systems is not more instable that productivity of conventional ones, an important result for farmers and future development of organic Horticulture.
-
Lower average yields but similar yield variability in organic versus conventional Horticulture. A meta-analysis
Agronomy for Sustainable Development, 2017Co-Authors: Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, Eric Malézieux, David MakowskiAbstract:Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on Horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic Horticulture are indeed on average 10 to 32% lower than those in conventional Horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic Horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic Horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional Horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.
-
Lower average yields but similar yield variability in organic versus conventional Horticulture
Agronomy for Sustainable Development, 2017Co-Authors: Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, Eric Malézieux, David MakowskiAbstract:Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on Horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic Horticulture are indeed on average 10 to 32% lower than those in conventional Horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic Horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic Horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional Horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.
Tamara Ben-ari - One of the best experts on this subject based on the ideXlab platform.
-
Yield variability in organic versus conventional systems : a meta-analysis for horticultural systems. PS-8.1-02
2018Co-Authors: Eric Malézieux, Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, David MakowskiAbstract:Organic agriculture has the potential to reduce the impacts of agriculture on humans and ecosystems but its productivity compared to conventional agriculture remains a contentious issue. Previous meta-analyses have shown that yields in organic systems are 10 to 25 % lower compared with conventional systems. However, those metaanalysis estimated the average yield gap of organic versus conventional farming systems but did not consider yields spatio-temporal variability. Although it is a major concern for farmers and food chains, only few studies analysed the relative variability of organic systems compared to conventional ones. Two contrary hypotheses exist in the literature. On the one hand, because of its reliance on biological and ecological processes, organic production can be assumed to be more vulnerable to pests and diseases outbreaks. On the other hand, organic farming systems are known to have a greater structural diversity and to optimize nutrient cycling and biological pest regulation, which may hence induce a higher resilience of the system and yields. Here we focus on Horticulture crops (fruits and vegetables) and make progress by estimating the variability of organic to conventional yield ratio across experiments and across years for a series of horticultural species from a meta-analysis of published field experiments. We define Horticulture as production systems based on vegetables and/or fruit production, both in fields, market gardens or orchards. We analyse a dataset including the results of 52 papers reporting yield data for 37 horticultural species in 17 countries. We find that yields in organic Horticulture are on average 10 to 32 % lower than those in conventional Horticulture. The variance of yields was not significantly different between organic and conventional systems, hence we find no evidence of a larger inter annual variability in organic versus conventional Horticulture. However, the coefficient of variation is significantly higher for organic yields vs. conventional ones reflecting the yield gap between these systems. We find no significant effect on yield ratios of type of crop, type of product nor type of climate. However, data on tropical zones were scarce. As a conclusion, despite lower yields, productivity of organic systems is not more instable that productivity of conventional ones, an important result for farmers and future development of organic Horticulture.
-
Lower average yields but similar yield variability in organic versus conventional Horticulture. A meta-analysis
Agronomy for Sustainable Development, 2017Co-Authors: Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, Eric Malézieux, David MakowskiAbstract:Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on Horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic Horticulture are indeed on average 10 to 32% lower than those in conventional Horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic Horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic Horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional Horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.
-
Lower average yields but similar yield variability in organic versus conventional Horticulture
Agronomy for Sustainable Development, 2017Co-Authors: Claire Lesur-dumoulin, Tamara Ben-ari, Christian Langlais, Eric Malézieux, David MakowskiAbstract:Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on Horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic Horticulture are indeed on average 10 to 32% lower than those in conventional Horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic Horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic Horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional Horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.
