Well, after a long period of time, part of Kansas is classified as abnormally dry. It happens to be centered in our area with Barton and the surrounding counties. This may change next week after some recent rains for part of the area but as this is written, Friday, the rains have been heavy but spotty. There is a chance of rain this weekend and we are moving into a more unsettled period. All our summer row crops definitely need the rain, corn, milo, and especially soybean fields where pods are starting to fill. Last week’s column described what factors make a good agricultural soil. How can move work towards the Goldilocks’ spot for soil physical and chemical conditions? If a soil is less than idea, how can we improve them?
• Our goal is to prevent wind and water erosion, maximize infiltration, optimize water holding capacity and aeration, and optimize the soil chemical environment.
• It isn’t practical to try and adjust soil texture, the relative proportions of sand, silt, and clay, on a large scale basis. For small areas, lawns, plant beds, and other small landscape or production areas, it is practical, but not cheap to “create” an ideal soil for the use. However, we can improve soil physical and chemical conditions in several ways.
• Before we proceed to the next bullet point, soil pH is a key factor working towards improved conditions. After appropriate testing, the pH is good, slightly acidic to slightly basic (6.2 – 7.2), basic (above 7.2), or acidic (below 6.2). Increasing the soil pH when acidic is a matter of the proper soil test to determine the amount of liming needed. There are a number of liming amendments from ag lime to burned lime. Once raised, with proper management, acidic soils should maintain proper pH for a period of years depending on the cropping patterns and cultural practices. For high pH soils on a field scale, there are amendments such as sulfuric acid and sulfate products to lower pH but they are normally cost prohibitive on a field scale. Instead, it is better to manage the problem through crop selection and where pH is high and soluble salts are present, through amending with gypsum, calcium sulfate, to improve structure and nutrient capacity.
• The most feasible way to improve soils is increasing the organic fraction of the soil. This includes humus, the stable fraction of organic matter, and organic matter serving as a food source for a variety of soil microorganisms and a nutrient supply for plants. It isn’t possible/practical to build organic matter levels quickly in a producers field but over a period of years with proper management possible. A one percent increase in organic matter will dramatically improve water and nutrient holding capacity as well as infiltration and aeration. Again, on a smaller basis (flowerbeds, gardens) you can rapidly increase organic matter levels through composting, purchasing humus, and manures. While not necessarily cheap, it is practical and easier to maintain higher levels for a small area..
• There are many sources to increase organic matter depending on you resources and location: manures, crop residues, compost, sewage sludge, etc. The challenge is what is available; what is the cost; what fits your operation; and what is your operation.
Next week: how to practically increase organic matter levels.
Dr. Victor L. Martin is the agriculture instructor/coordinator for Barton Community College. He can be reached at 620-792-9207, ext. 207.
