Soil temperature associated with degradable, non-degradable plastic and organic mulches and their effect on biomass production, enzyme activities and seed yield of winter rapeseed (Brassica napus L.).

摘要

As efforts to improve diets in high income countries intensify, attention has turned to how policies may influence diet composition. The case studies in this special issue contribute to our understanding of how two main types of policies have influenced food product composition and dietary outcomes: (1) policies affecting food manufacturers' input costs and (2) information policy affecting competition. Research on the first type of policy is relatively new, but suggests that US commodity policies would not be good policy instruments to influence diets, except through the long run impacts of agricultural research. Research on the impacts of information policy continues to demonstrate that it can spur food industry competition to introduce healthier products, but may not result in healthier diets. International comparisons show where the US experience may have relevance for other high income countries.