tim ar - 11/3/2017 05:29

Replicated plot data across multiple locations and years would be far more convincing than a survey. 
As a ag research phd friend told me once regarding the various snake oils being hawked to farmers " if all they have is testimonials and pictures of roots you can bet your a$$ they don't have any data"
That's not to say the covers don't work. I've grown wheat for grain for years and no-till beans right behind the combine which amount to the same thing as covers with good success. The wheat itself was often notill soon after the combine harvesting a summer crop. I'm dabbling now in crops grown strictly for cover. I think there is potential. I simply don't put much faith in surveys or testimonials.