Biotech Crops, Input Use and Landslides: The case of Genetically Modified Corn in the Philippine Highlands

Improved seeds varieties have led to an increase in agricultural production as well as to a change in agricultural practices and input use. A side effect of these changes that has received little attention to date is the impact of those new technologies on environmental degradation. Using an original survey method of farming households on the Philippine island of Mindanao covering the past ten years, this paper finds a positive correlation between GM corn cultivation and landslide occurrence, which is robust to the inclusion of household fixed effects as well as to the use of matching and survival models. An endogenous allocation of crops on plots can be ruled out as a mechanism. Instead, more aggressive weed control via broad-spectrum herbicide appears to explain the results. Looking at the distribution of landslides as a function of wealth, landslides are found to increase socio-economic inequality as poorer farmers lose on average a significantly larger portion of their plots to landslides while for the top tail of the landholding distribution is less affected.