How wheat uses water
Water isn’t something that necessarily comes to mind when you think about dryland wheat. But like with most plants, water is incredibly important to growing wheat. Through the natural water cycle of the region, Washington’s wheat farmers are able to work with nature to grow wheat in the desert. Though working with the water cycle is something that’s been done for hundreds of years, it’s truly something to marvel at.
Water finds its way to us in many forms. We receive it through our water taps from pipes connected to rivers, reservoirs, and aquifers. We also receive various forms of precipitation, including rain, snow, hail and sleet. In Washington state, different parts of the state get different amounts of precipitation. The areas west of the Cascade mountains tend to get up to 50 or 60 inches of rainfall, and the areas east of the mountains usually get less than 18 inches of rainfall each year.
On the farms of Eastern Washington, precipitation in the forms of rain and snow is very important to help grow wheat. In the winter months snow builds upon the fields. As the weather begins to warm up, the snow melts. As all those snowflakes melt, they turn into water droplets. Those water droplets seep down into whatever surface they were resting on during the winter. In this case, the water drops into the farmer's soil. This is known as moisture in the soil.
In the spring, we often get more precipitation, adding to the existing moisture already in the soil. On warm days, some of the moisture may evaporate back up into the air. When conditions are ready in the spring, wheat farmers plant their spring wheat crop into the soil. They put the seed at just the right depth in the moisture, so the seeds can have a nice, moist place to grow.
As the seeds sit in the soil, they get busy growing as more moisture tends to evaporate into the air. This moisture collects and makes droplets again, and they end up forming clouds. The rest of the water drops remaining in the soil begin dropping slowly down further in the soil. After a few days, the wheat seed germinates, which means the seed has started to grow and has broken the seed coat. Meanwhile, our moisture level naturally drops further down into the soil.
Roots form and the first shoot, also called a tiller, grows up from the ground. The roots’ job is to feed the plant. They start to follow the moisture level further down into the soil.
As the wheat plants continue to grow, they start the jointing and booting process. During jointing, the shoots continue to grow to form nodes and eventually leaves. During booting the head of the wheat plant grows from the top of the stem and has the last leaf wrapped around it. Meanwhile underground the roots continue to chase the moisture level downward.
Sometimes we get spring rains that help keep the soil moist near the top of the surface so the roots don’t have to grow so deep to find water. But sometimes we don’t get enough rain in the spring and farmers face what’s called a “drought”.
During an average year, the wheat plants grow big, plump heads and the plants stay green for a while. During a drought, when the plants have gotten very little water to drink, the plants have tiny heads and the leaves are thin. The wheat plants ripen faster and turn yellow quickly.
Once the wheat plant is ripe, it is ready to be harvested. Farmers use a big machine called a combine to cut and separate the kernels from the stalk and leaves.
Meanwhile, the leftover water we received from snow continues its journey down into the ground. It travels hundreds of feet over a long period of time, eventually arriving at our underground river system, called the aquifer. There, our old snowdrop joins the aquifer.
While in the aquifer, our snowdrops could become drinking water for our homes through the pipes pumping water up from the aquifer to the surface. Or it could continue along the aquifer and eventually make its way to the ocean. Once at the ocean, it could stay there for a long time, or it could evaporate up into the air and form a cloud. And eventually end up as another snowflake or raindrop, ready to help our wheat farmers again!