income classification based on the world bank income classification this has tended to be the case in the majority of oecd countries although the degree of protection and other forms of tradedistorting support has declined significantly over the past years box however comparative advantages in food production are not irreversibly fixed while heavily influenced by initial endowments of land water climate topography soils and the prevalence of pests and diseases whether a country is a net food exporter or importer also depends on its past investments in agriculturerelated physical and human capital in institutionbuilding and in technology improvement