Green is good. Blue is BAD. It is June and the Palouse is wearing its multiple shades of green. The deep green of the winter wheat, the soft green winter barley, light green and different texture of peas, and the airy, ferny, fuzzy green of the garbanzos make a mosaic that has the county roads and secondary highways swarming with photographers trying to capture it all. A farmer’s eye, however is starting to see blue. Blue is the color of moisture stress in wheat and other crops, and stress means lower yield. Moisture stress in June is bad news, moisture stress in early to mid-June is really bad news.
Moisture stress first shows up in the color change. The plant leaves develop an extra heavy waxy cuticle that slows moisture loss. If it gets bad enough, wheat leaves actually roll up to reduce their exposed surface area and further restrict water loss. Leaves begin to brown at the tips and edges. Next comes early heading, early maturity, and early death with shriveled, shrunken seed of poor quality. It is a similar story with all other field crops. Kansas has been having severe moisture stress this year, and if we don’t see substantial, widespread rain in the Palouse soon, we will be in a similar situation.
The blue tinge first shows on shallow or exposed clay subsoils that don’t have the water holding capacity of our Palouse Silt Loam soils. I have been seeing those blue areas in my fields for a week or so now, and they continue to expand. Those areas are always first to ripen, going from green to golden brown, but they shouldn’t be visible now. Ideally, they shouldn’t be seen till about the fourth of July. There have been scattered thunder showers over the last two weeks, and fields lucky enough to get dumped on by one of these cells should be in good shape, but if not, the “outlook is less than favorable.”
How bad? It’s impossible to tell right now. It is amazing how a few days difference in maturity between different varieties can make big differences in yields and quality with weather conditions like this. It all depends on what physiological stage of maturity the majority of plants are in when drought stress (or drought relief in the form of a rain shower) strikes. The plants seem to hang on and cope with mid 70’s temperatures, but a windy 85 degree day can dramatically change things in 24 hours. It is a lot like watching the stock market, or the value of your 401K fall – you can see the dollars going away, and there is nothing you can do. Unlike a financial investment, though, I can’t sell and stop the loss. I have to wait for the eventual harvest to find out just how much I have lost.
And, maybe we will get a half inch of rain before it is too late, and everything will be great. We will know in August when harvest gets underway. In the mean time, the agenda is spot spray the perennial weeds, keep an eye on the legumes for insect damage, and get the combines and trucks ready because harvest will be here soon.