The picture below says it all. We could go on for 1,000 words and it wouldn't be clearer than it is in the picture. This farmer worked his soil with conventional tillage, at least two trips in the spring, and then a "goose-drowner" rain hit. It takes a lot of rain to drown a goose! It's definitely enough rain to pack soil if there is no residue there to help deflect the impact of raindrops on the soil.
Now the farmer is out there with a putty knife, something strong enough to get through the crust, wondering if the corn will come up or if he will have to replant it. As it turns out, which you can't tell from the picture, he lucked out. A couple days after this photo was taken this field received a gentle, half-inch rain. Enough corn emerged to make it a stand too good to tear up. With the excellent year that followed, the corn yielded reasonably well.
If that gentle rain had not arrived, then what? Would a rotary hoe help? Maybe. Some believe that's old technology.
Bill Lehmkuhl, a farmer and crops consultant from Minster, Ohio, recently talked to a group of Indiana farmers about getting good stands with corn. Lehmkuhl says you need to think carefully about every tillage trip; ask yourself why you are doing it and what it will do for or to the soil. Will it put in layers at certain depths that will slow down roots, causing them to turn and costing bushels by the end of the season?
Although he is 80% no-till on his own farm, he realizes that there are reasons for tillage in some cases. But he suggests people need to think harder about what they are doing in terms of tillage and why they are doing it, especially on lighter soils like the one in the picture.
Related: How to do tillage the right way
What you see in the picture is a worst-case scenario – a crust due to beating rain on tilled soil with limited organic matter. Unfortunately, it's not a rare scenario!