By Dave Nanda, Seed Consultants, Inc.
We have discussed what pH is and the importance of having balanced pH during the last three weeks. Many physical, chemical and biological processes necessary for crop survival, growth and yield are affected by soil pH. I would like to discuss how you can adjust the pH in the soils on your farm.
• For high yields we must balance soil pH depending on the crops we intend to grow. For growing corn, beans, wheat and alfalfa, we need to have a soil pH values of 6.0 to 6.8. Balanced pH is critical because it can affect nutrient availability, soil-applied herbicides and their degradation, potential for aluminum or iron toxicity, as well as nitrogen fixation by legumes.
• Some soils have a tendency to become acidic over time due to weathering of soil minerals and release of acidifying metals, leaching away of calcium, potassium, magnesium and sodium, decomposition of organic matter, and application of ammonia-based fertilizers.
• For effective soil pH management, soil testing every 2 to 4 years for every field is important. Soil samples should be collected at the same time every year.
• Liming to increase soil pH of acidic soils is based on soil type, tillage depth and lime quality. Clay soils with higher organic matter require larger amounts of lime than sandy soils with low organic content.
• Fine lime with smaller particles dissolves faster and neutralizes soil acidity more quickly. There are many types of liming material available.
• Some of the most common types of liming materials are calcite or calcium, the most commonly available form of lime. Dolomite contains both calcium and magnesium. Burned lime, hydrated, slag, pelleted and fly ash are some other types available.
• Soil type, level of acidity, crop to grown, type and depth of tillage would determine the amount of lime you need to apply. Check with your Extension agent for specific recommendations.