[zander312]

We have known for years that erosion is far greater from tilled soil than from ungrazed or wildlife grazed rough native pastures. The evidence comes from many erosion plots around the world where you mark off a plot of maybe 20 yards by 20 yards and put a V shaped funnel arrangement at the lower end and weigh what you catch washed out over say a year.

But there are lots of other questions. We don’t have much data on rates of soil formation from underlying rock and moisture. And the problem is that actually many of the world’s best soils are the product of erosion. Often, when fields get eroded, the soil just moves downhill to another location. The Nile delta in Egypt and the Ganges plains in India are excellent soils that came from erosion in other places over millions of years.

They are right that zero till usually somewhat reduces erosion. But this technology is under threat because people claim that the herbicide Roundup used before direct seeding causes cancer. ( The evidence for that is very shaky. A large US study of about 40,000 professional Roundup applicators contracted by farmers, who must have had a high level of contact with it, had no higher cancer rates including lymphoma than the average.) Also, farmers, who use a lot themselves, are probably the healthiest demographic in the world.

It’s a complex story.