I think the impact of something like no-till farming has been huge. Certainly it has been down in the States, where around 18 million acres are now grown by no-till farming. People don't realize just how much carbon dioxide is released into the atmosphere by farming in this country. Something like all the carbon dioxide released from farming until 1985 was more than all the carbon dioxide released by burning fossil fuels—a huge amount. What we can do now is start reversing this by no-till farming, which is really effective.
It also goes to the question you were talking about, and that is erosion. The cost of erosion is huge in terms of losing topsoil. Until recently in Iowa, 50% of the topsoil had been lost through erosion since the time of agriculture.
You can't carry on doing this. You have to start building up new soil. The way to do that is to plough in the remains of one crop and then seed directly into it.
The advantage is simply huge. And not only is there a huge environmental advantage with the carbons in the soil, but there's advantage for a lot of the small animals that live in these areas as well.