Comparing productivity of organic and conventional farming systems: a quantitative review

Abstract

For decades, there has been debate about the possibility that organic farming can feed the world’s population. The most recent studies, analyzing the yields of individual crops, show a yield gap between organic and conventional farming. The rotations and the intensity of soil use are also different between systems and the impact of this factor on productivity has not been assessed. A meta-analysis of the yield data of organic and conventional crops and the intensity of soil use (years with harvest crop in relation to rotation duration) was carried out using studies published in peer-reviewed journals. The yields under organic farming were on average 25% lower than the conventional ones, reaching a yield gap of 30% for cereals. The intensity of soil use was also lower in organic systems, the size of the reduction depending on the type of study: field experiments (7%) or on-farm studies (20%). Combining the yield gap with the reduction in the number of crops harvested in the rotation, a productivity gap of 29% to 44% was estimated depending on the type of crops included in the rotation. These results show that the productivity gap is greater than the yield gap between organic and conventional farming.