A number of studies (for example, refs 65,66) have compared
ecosystem services in organic and conventional farming systems.
A few of these studies have accounted for the monetary value of
ecosystem services; these studies generally show that conventional
practices decrease the ability of farms to provide some economically
significant ecosystem services relative to organic practices67–69. For
example, in a study comparing 14 organic arable fields with 15 conventional
ones in New Zealand70, the total economic value of three
ecosystem services (biological pest control, soil formation and the
mineralization of plant nutrients) in the organic fields was significantly
greater at US$232 ha−1 yr−1 compared with the conventional
fields at US$146 ha−1 yr−1. Factoring in such differences in economic
comparison studies would probably make up for price premiums awarded to organic products. Price premiums and European subsidies
for organic farms are often justified on the grounds that they
compensate farmers for providing ecosystem services or avoiding
damage to the environment.