Wheat-sorghum-fallow has been the gold standard of crop rotations on the High Plains. It has performed in good times and bad for decades. But does this tried and true rotation hold value in abysmal years like 2011 and 2012?
Already half way through 2012, we are severely behind on moisture with an accumulation of about 4" for the year, compared to a normal accumulation of around 11" since January. The moisture deficit we inherited from last year only exacerbated the dry spring.
Add in the record heat in May and the abnormally warm winter, and this year was the final exam on whether wheat-sorghum-fallow is the bullet-proof rotation for our part of the plains. Our wheat yields this year didn't hold any secrets. Any wheat field that followed milo ranked the lowest in performance, with our worst field coming in at 6.7 bu/acre - barely covering the cost of harvesting. Our best fields, meanwhile, were all in wheat-fallow with our top field yielding just under 60 bu/acre.
In these severe drought years, yield differences in rotations are greatly magnified. Anything that is more intense than the simplest, most conservative rotation now becomes high risk. Beyond wheat-sorghum-fallow, other rotations start looking nuts, such as continuous milo or continuous wheat, also known as five-minute fallow.
Rotations that included cover crops this year took failure to a new level. In our region of west-central Kansas, most of the wheat fields that followed a cover crop weren't even harvested as the cover crop used up all available topsoil and subsoil moisture, leaving nothing for the wheat to survive on. Most of those fields didn't even produce a head in May. In semi-arid western Kansas, that rotation is almost guaranteed to be high risk in any year…and should be non-insurable. In drought years, it becomes a death sentence.
When the drought breaks, which is something we have to keep hoping for daily, we'll go back to having more milo in our rotation. But for now, our preferred crop rotation is wheat-fallow. In drought prone regions like the High Plains, only conservative crop rotations that stretch moisture make any sense.