Discussion
atmospheric COA
SECONDARY, SAID
Improved agricultural technologies can make large contributions to economic growth, poverty reduction, and improved health and nutrition in many of the poorest countries in the world. Whether such potential gains come at the cost of environmental sustainability is a long-standing question. The Borlaug hypothesis states that the availability of Green Revolution agricultural technologies (essentially modern seed varieties and fertilizers) helps prevent expanding the land area under cultivation, but theory (such as Jevon’s paradox) and characteristics of local markets, tell us this does not necessarily hold locally.This question is of particular relevance to DR Congo, home to the second-largest rainforest in the world. Since 2000, deforestation in the Congo Basin has increased substantially, 90% of which is linked to small-scale non-mechanized forest clearing for smallholder agricultureThe contributions of this paper are twofold: first, we provide a causal test of the impact of the promotion of modern seed varieties on deforestation through a randomized control trial. Second, we establish the importance of distinguishing between primary and secondary forest deforestation and point to the importance of soil fertility considerations.Our results show that overall, the promotion of modern seed varieties did not lead to an increase in the demand for land or related deforestation, but neither did it reduce land in agricultural use. Hence when considering all deforestation together, we find no strong support for either the Borlaug hypothesis or Jevon’s paradox. Inelasticities in labor supply may explain why there was no change in overall deforestation in the study area. As deforestation is a labor-intensive activity, and opportunities to hire additional labor are limited, households mostly need to rely on the reallocation of a fixed labor supply.We further find that exposure to modern varieties changed the nature of deforestation. We hypothesized this is driven by an increase in demand for soil nutrients generated by modern seed varieties for cereals, which was met neither by local fertilizer markets nor the government’s agricultural rehabilitation project. In the Congo Basin forest of Equateur, the absence of fertilizers and the lack of information on soil conservation practices meant that previously uncultivated land gave the highest cereal yields—a feature that local farmers are well aware of, following land-and-crop rotation recommendations introduced by agronomists during colonial times. In this setting, smallholder farmers with increased access to modern cereal varieties accelerated the clearing of the primary forest while cultivating less land converted from the secondary forest or other land uses. Exogenous variation in the type of seeds that were offered to farmers helps understand the mechanism. Where cereals were the predominant modern seed variety offered, subsidies led to an increase in the deforestation of the primary forest by beneficiary households. In contrast, modern seed variety promotion led to more limited deforestation in villages where more legumes were available for purchase, in line with the historical recommendations that legumes be planted on poorer soils given their lower need for nitrogen. This last finding comes with a caveat, as the random variation in the availability of cereals versus legumes was not planned for in the original experimental design. The increased access to legumes is found in villages where a larger proportion of treated households used their subsidies and they bought smaller quantities. We cannot fully rule out that these other differences also influenced land conversion decisions. Distinguishing farmers’ soil fertility management decisions for legumes versus cereals hence deserves further research with experimental variation in exposure to different crops. Even so, the results in this study point to the importance of promoting modern seed varieties in combination with soil fertility management practices to achieve sustainable intensification, especially in contexts where smallholders use the primary forest as a source of nitrogen for improved cereals cultivation, asAn important contribution of the study is to demonstrate the value of distinguishing between primary and secondary forest deforestation. The distinction both reflects decision-making at the household level and has major ramifications for biodiversity. Tropical forests support at least two-thirds of the world’s biodiversityDistinguishing between deforestation from primary and secondary forest hence is key to understanding the environmental trade-offs involved with agricultural intensification practices. While modern crop varieties have a large potential to improve livelihoods, the tension with possible negative effects on environmental outcomes needs to be considered in nuanced and context-specific ways. Our results show that improving access to modern cereal varieties in the Congo Basin, in the absence of accompanying policies to improve soil fertility management, may have a high cost for biodiversity due to its effects on the primary forest.The distinction between forest types can also be important for understanding the carbon sequestration implications of deforestation. While secondary forest can sequester atmospheric COA possible caveat to this study is that it relies on farmers’ ability to distinguish between primary and secondary forest, and imperfect recall may introduce some measurement errors. That said, given the important implications of deforestation of primary forest in terms of labor efforts, it seems reasonable to assume farmers remember the type of land they cleared. In addition, misclassification would bias the results only if it is systematically related to the randomized allocation of treatment, which is unlikely. Another potential caveat is that we rely on farmers’ estimates of plot sizes and, therefore, of the area that was converted from the forest. While these estimates are likely to be imprecise, the main results hold when we consider the extensive margin.Finally, as is the case for almost any other RCT analyzing agricultural decision-making, a more general caveat is that the interpretation of the results needs to account for the specific context and time period in which they were obtained. The findings are likely most relevant for remote rural areas, with missing or imperfect farm input and output markets and increasing pressure on forest resources. Of course, these are also exactly the types of contexts where deforestation of remaining primary forest is policy relevant. The results contribute to discussions on sustainable intensification practices that aim to reduce productivity-environment trade-offs by stepping away from the modern seed variety plus mineral fertilizer intensification packages