You may have used the same techniques in your field for 20 years and never had a problem. Then, using that same technique on this year's corn or soybeans planting doesn't work. Of course, if everything is at a lower yield level, the difference may not be a big deal. But it's an opportunity to evaluate what worked and what didn't, and decide if this was just a freak year, or if you should adjust your practice.
Here's a concrete example. Many people who sidedress nitrogen on corn use toolbars that run down the middle between every row. Each row of corn plants can access N from both sides. But some people, particularly if they have put some N down early, opt to only run knives in every other row. In theory, plants will get N from one side or the other.
That has likely worked well in years with plenty of moisture. But this year, when roots are having trouble finding N in dry soil in any situation, this practice may have aggravated the plant's attempt to find N. It had to go to one side to find it. N wasn't applied at the full rate on the other side of the plant. The practice may have saved horsepower and diesel fuel, but this year it may have cost anyone who tried it valuable bushels, assuming their field produced a crop.
In one instance we visited, where corn should make 110 to 120 bushels per acre, there was a marked difference in some cases from one row to the next. Why one row reached out and got N from the middle and the next row didn't is for agronomists to figure out. What we observed is that it happened. In one instance, we estimate a 30 bushel difference from one row to the row beside it. The row with the lower yield was definitely showing more signs of N deficiency, including smaller diameter stalks and smaller ears.
If there is anything that can come from this forgettable season, it may be that it exposes the flaws of certain practices, even if they work in 19 years out of 20.