Great Bend Tribune
March 25, 2018
Finally, after over five months of essentially nonexistent precipitation, most of the area received significant moisture with some places receiving well over an inch. The title of this column is a bit tongue and cheek and it is safe to assume we all know the drought is nowhere near over and in fact conditions are little improved. In fact for much of the area the drought rating improved only marginally as dry as the State continues to be.
Did this moisture help? The moisture received made a significant impact on soil moisture conditions but in this case they improved from extremely dire to extremely dry. Even in those areas receiving moisture in the two inch range, the soil was extremely dry. So while it infiltrated into the soil and was adsorbed into the profile, there was insufficient moisture to recharge more than the surface or top soil part of the profile. This leads to several other questions worth considering.
- What is a drought? We all know a drought when we see one but can you define what a drought is? There is no one definition for a drought. Is it simply a lack of precipitation? No. Is it a lack of soil moisture? Sort of. Drought for an area concerns two major factors. First, what is the normal for an area in terms of precipitation? A “drought” for SE Kansas may be close to average or even slightly above for Barton County. Second, in addition to a lack of precipitation, what is the moisture status of the soil? That depends on several factors including how much soil moisture there is at a starting point and how does it change over time? How soil moisture changes over time is a function biological activity and weather (temperature, humidity, etc.). So an area can lack moisture and yet still not descend into severe drought depending on conditions. To keep people happy, some consider a drought a period of time with less than 75% of expected rainfall.
- Do we need a full profile to end drought conditions and to produce a wheat crop? The easy answer to this question is no. A drought ends when conditions, especially soil moisture return to normal status for the time period. And to produce a wheat crop you need timely rains, not an end to the drought. And it is possible to produce a decent volume, high quality wheat with little precipitation provided there is good subsoil moisture and/or rain falls at just the right time.
- Do we need a full profile to establish and produce adequate summer row crops? No but it would be helpful. If we cannot get topsoil moisture and subsoil moisture recharge, we will have to rely on just in time precipitation and as the season progresses the slightest stress has major yield implications.
- What does it take to end the drought? Well above normal precipitation for an extended period of time in order to recharge soil moisture and temperatures, humidity, wind, and biological activity allowing for moisture to accumulate and stay in the soil. So it is possible to have good rainfall yet make little progress on the drought.