The Economists take on the meta-study we posted last week. -JP Commercial genetic modification for crops comes in two forms. One makes them resistant to insect pests. The other confers tolerance to glyphosate, enabling farmers to spray their fields with this herbicide and kill off all the other plants (ie, the weeds) in them. As a consequence, the study found, herbicide-tolerant crops have lower production costs—though this was not true for insect-resistant crops, where the need for less pesticide was offset by higher seed prices, and overall production costs were thus about the same as for unmodified crops. With both forms of modification, however, the yield rise was so great (9% above non-GM crops for herbicide tolerance and 25% above for insect resistance) that farmers who adopted GM crops made 69% higher profits than those who did not. In debates about GM the methodology of studies has often generated as much controversy as the crops themselves. Drs Klümper and Qaim have done something to moderate these controversies, too. Though some studies they include were not peer-reviewed, and a few of the early ones did not report sample sizes, limiting their value, the data they used for the meta-analysis—which include conference papers, working papers and book chapters as well as work published in academic journals—may correct for perceived publication bias, the tendency of journals to publish only the most dramatic findings. This large body of evidence enabled the authors to control for possible differences in matters other than whether a crop was modified or not, such as fertiliser use. They also found that who pays for a study does not seem to influence its results.
Posted on: Mon, 10 Nov 2014 15:35:58 +0000
Recently Viewed Topics
© 2015