The drought monitor report as of Tuesday, Aug. 2, indicates the same conditions as we continue to see severe and extreme drought. The recent rains helped the extreme western counties a bit. Only Northeast Kansas is in good shape. The six to ten-day outlook (Aug. 9 to 13) indicates a 50 to 70% chance of above normal temperatures (our area is right on the line) and believe it or not, a 40 to 50% chance of below normal precipitation. The eight to 14-day outlook (Aug. 11 to 17) indicates a 50 to 60% chance of above normal temperatures and 33 to 40% chance of below normal precipitation. Exactly what our summer crops don’t need. While most of the corn is pretty far along and mostly what is there is there, this forecast is very bad news for the dryland soybean crop and not much better for grain sorghum and hay crops. Definitely the year to check for nitrates in Sudan grass, and sorghum x Sudan hybrids. Today, how can we work to improve our soil to help crops and stay economically viable with the weather extremes that are becoming the norm?
The weather patterns are indicating a long-term change due to climate change, not just here but around the world, in brief wetter wet periods and drier dry periods combined with extremes of temperatures. Models suggest our region of the country will be drier and hotter in summer. Essentially, the weather typical of western Oklahoma and Texas is shifting north. We have discussed how this likely affects our cropping practices and how we may be able to cope. Here are some suggestions for what we can do to maximize our soil environment.
As stated before, we can’t really change our soil texture, but we can improve infiltration, water holding capacity, and nutrient retention. The key is finding a way to increase organic matter content and promote a stable soil structure with as large an interconnected macropore network as possible. So how can that be done?
• Minimize or where possible eliminate tillage. Maintain as much residue cover on the soil surface as possible while promoting an increase in below ground organic matter. It sounds counter-intuitive with concerns about soil moisture but cover crops, especially those crops with fibrous root systems. This isn’t easy as when tillage is eliminated it can take five years or longer depending on the weather to develop the needed structure and start to slowly increase organic matter. Weed control is more difficult. Cover crops and newer chemistries and technologies can help as well as diverse as a crop rotation as possible.
• Maintaining adequate residue cover also helps decrease soil moisture evaporation.
• Maintain as cool a soil environment as possible. Moderate root temperatures are the second key, especially during hot, dry periods. It allows plants to hold on better and decreases soil moisture loss. It also helps winter wheat to moderate soil temperature. Residue cover helps moderate soil temperatures and temperatures swings two ways. In the summer it decreases available solar energy entering the soil for evaporation while also serving as a water vapor barrier. And by conserving soil moisture it means soils will cool and warm more slowly and to a lesser extent. Finally, crop canopy closure also aids in conserving moisture and moderating temperatures.
Dr. Victor L. Martin is the agriculture instructor/coordinator for Barton Community College. He can be reached at 620-792-9207, ext. 207, or martinv@bartonccc.edu.
