How is wheat affected by drought?
Droughts create a shortage of water that can affect all parts of life, but has the greatest impact on agricultural production.
Wheat is remarkably adaptable, but drought conditions mean bad news for this harvest - and the next. Wheat plants are influenced by factors like moisture and heat, planting time, and overall soil health. If there’s plenty of moisture when the wheat is planted in the fall, it will put out multiple tillers (additional stems from the main plant). In a normal year, this is a great sign of a healthy thriving plant.
The problem arises later in the growing cycle if the plant doesn’t have enough moisture to “fill out” the tillers that it started. The plant will “abort” tillers at any point in the growing cycle if there’s not enough moisture. Farmers call them “blanks” - empty husks which the plant started but wasn’t able to fill with kernels.
If moisture is extremely scarce (like summer 2021), farmers report that up to 50% of their field may be filled with these blanks.
Blanks mean fewer kernels are harvested per acre so there’s less grain to sell - but the cost to harvest doesn’t go down. Farmers are faced with a tough choice: spend the money on fuel to proceed with a meager harvest, or abandon fields and look forward to next year?
But what if next year's harvest is just as bad?
In parts of Washington’s wheat country, a severe drought won’t only impact this year’s crop, but also next year’s - even if there’s plenty of rain next summer!
Some farmers in low-rainfall zones use a "fallow rotation" system, in which they leave fields unplanted for a whole year after harvest. That year allows the soil to absorb moisture for a whole year before being tasked to grow another crop. (Many farmers use a three-year cycle to perfectly utilize the precise amount of rainfall they receive.) Essentially, wheat crops in these low-rainfall zones depend on two years' worth of moisture to produce a crop. So crops this year are suffering through a drought - but next year's crop will be affected just as much, if not more.
After they're planted (at a very specific depth, depending on the region), moisture is what triggers the seed to sprout - so if there's not sufficient moisture in the soil when the seeds are planted, fewer seeds will even reach the germination stage. For those seeds that do germinate in dry soil, the plant will put out significantly fewer tillers than normal. So even if there's plenty of rainfall later in the season, the plant is already limited in how many kernels it can produce. And those wheat kernels that eventually get harvested can be drastically different than normal.
A protein problem
One of the unexpected side effects of drought conditions is that the wheat kernels themselves can be transformed by lack of moisture.
In a typical year, soft white wheat (the predominant variety grown in Washington) has low protein content compared to other wheat varieties. This is part of what makes soft white wheat perfect for light and fluffy pastries, cakes, and cookies.
But in drought conditions, with fewer kernels to support, plants pump more protein into each one. Protein levels can jump from a normal level of 8.5% to more than 10.5% - a massive change. To add insult to the injury of low crop yield, farmers often have to discount any wheat with high levels of protein.
Washington has some of the best farmers in the world, who are experts at growing wheat in a semi-desert climate - but even they are subject to the weather patterns of Mother Nature!