Thursday was Jack Kilby Science Day at Barton with hundreds of area high school students in attendance. After the main presentation, students attended two different sessions from 10 a.m. until noon. When the morning started it was bright and sunny without a cloud in the sky. At first glance, looking out a window at noon indicated it must have turned cloudy. Going outside, it only took seconds to realize there weren’t any clouds in the sky. Visibility was less than a half-mile and the sun obscured by soil suspended in the atmosphere. The wind had picked up since morning to well over 30 miles per hour, with gusts approaching 50. A great deal of newly planted wheat was being scoured by wind-driven soil and unemerged wheat ground being blown clean. This was an unpleasant reminder of just how nasty weather can be for people and crops. So what happened?
Even though we have been dealing with drought and heat over the last year, the wind really hadn’t been extreme, at least for Kansas. The rains the area received over the last six to eight weeks encouraged wheat planting, especially with so many failed acres over the summer and a good price. Many fields were weedy, weeds seem to thrive no matter the conditions, and many were brought on with the earlier rains. Also even with the rain a lot of the ground was hard. While some herbicides were used and the wheat planted without tillage, much of the ground was tilled. Most, not all, of the producers who tilled attempted to leave enough residue cover to hold the soil and leave some larger soil aggregates. Some, while not moldboard plowing, pulverized the ground into essentially powder with absolutely no residue on the soil surface. Then last weekend much of the area received significant rainfall of up to two plus inches. This rain crusted the well-worked ground, especially without cover. Then the area received several warm, sunny, breezy days which dried out the surface of the soil. Now all that was needed was wind.
Wednesday was windy but not excessively so. However, on Thursday in response to a storm system off to the northeast generating a large pressure gradient, the wind started to howl. Where the wheat had emerged and was covering the ground well, the soil stayed in place. Where the wheat hadn’t emerged or hadn’t started to tiller and cover the ground, the wind provided the energy for the soil to move. Once the first few soil particles move it starts a cascade effect knocking other particles into the air and you in essence have an avalanche. The sand particles in soil are heavy enough they don’t tend to go far but bounce across the surface. The sand particles are quite effective in destroying young plants. These plants if not buried too deeply under the soil, can recover but may be significantly set back. What stays in the air are the lighter particles, silt and clay. The clay can stay in the air the longest and under the right circumstances travel hundreds, even thousands, of miles before returning to earth.
It’s not the end of the world and farming has certainly made progress in making wind erosion rarer. The big problem is that it can take hundreds of years to regenerate a lost inch of topsoil. What we have lost is more surface moisture, set some fields back, and potentially lost nutrients. What we need is the development of better more reliable crop rotations allowing for less continuous cropping and that will allow producers to reduce tillage while still producing acceptable yields without having to invest in larger fertilizer and pest control inputs.