The drought monitor report as of Tuesday, June 24 shows conditions unchanged for the state with 66% of the state totally out of dry conditions. Essentially, the southern two-thirds of Kansas is almost totally out of dry conditions. The only parts of the state with some moderate and a bit of severe drought continue along the Nebraska border. Barton County is totally out of moderate drought with the southern three-quarters just abnormally dry. Keep in mind this rating doesn’t include all the recent rain. The six-to 10-day outlook (July 1-5) indicates near normal temperatures and a 40% to 50% chance of leaning above normal for precipitation. The eight to 14-day outlook (July 3-9) indicates continued near normal temperatures and a 33% to 40% chance of leaning above normal for precipitation. Not so great for the wheat harvest, but good news for our fall crops, especially corn.
Soils are the medium for growing most of our plant based food, fiber, and fuel. Just like any other living organism, plants have an optimum environment which can vary from species to species. For our primary crop plants, the variation is less. Let’s look at that part of the plant environment we don’t see — the soil. What does an “ideal” soil consist of? For today, the non-living part of the soil environment.
• An ideal soil should be 50% “stuff” and 50% “not stuff.” The 50% “stuff” should be broken down into 45% mineral and 5% organic matter. The “not stuff” space should be half air and half water. The mineral fraction defining a soil is composed of three soil particles — sand, silt, and clay. For most plants, a loamy type of soil (acting like equal parts of the three) is ideal. The organic matter fraction should be mostly stable and well-decomposed, the black stuff. This results in ideal water and nutrient holding capacity.
• The ideal soil structure is termed crumbly, or granular. Its bulk density, weight per unit volume, should be around 1.2 to 1.3 grams per cubic centimeter. Not too dense and not too loose. It should contain a continuous pore system with a range of pore sizes from micro-to macro-pores. This allows for water infiltration and storage, root exploration, and air movement. The structure should be stable if left alone. The soil surface is ideally covered or shaded with vegetative growth or crop residue. This aids in water infiltration, while decreasing evaporative soil water loss and runoff/erosion. It also provides for a cooler soil environment during the heat of summer.
• Finally, chemically the soil pH level should be slightly basic to just above neutral for most crop plants. This isn’t only ideal for the plants roots system but is also the pH range where the seventeen essential crop nutrients are available in proper amounts. Outside this range nutrient availability can result in deficiencies or toxicities. And for certain soil types, aluminum can become available in toxic amounts.
Next week: How to make soil as ideal as practical.
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.
