Core Aeration

HOW MUCH FIELD AREA DOES YOUR CORE CULTIVATION PROGRAM ACTUALLY IMPACT?

By D.D. Minner, Iowa State University

Use the following tables to determine how much of the field area is actually being impacted by your coring program. Did you realize that using a 3/4-inch hollow tine more than doubles the area of the field that is impacted compared to a 1/2-inch tine? Let's suppose that your goal is to remove 50% of the field area to a depth of your aerifier tine. The field is predominately clay and you want to begin to remove it from the field and replace it with sand. If you remove cores on 3-inch centers, it will require 22 passes over the field using 1/2-inch hollow tines in order to meet your goal of removing 50% of the clay soil. At two corings per year this would require 11 years and that might be too long to wait. By using 3/4-inch tines you can achieve the same goal in 10 passes over the field. If you increase your aerification and topdressing to three times per year you can achieve your goal of replacing 50% of the surface in nearly three years.

In the case of soil modification, the most effective modification, greatest change in physical properties with the least amount of added sand, has been obtained from sands in the very coarse to coarse size range. Rounded sands that are narrowly graded and have coefficient of uniformity less than 2 are preferred. Select a uniform coarse sand (80% of the particles between 1.0 and 0.5 mm and 90% between 2.0 and 0.5 mm) to maximize large pore space when modifying native soil fields high in silt and clay. Mixtures of predominately coarse and medium sand, with some fine sand, are best for amending native soils. Adding very fine sand or silt and clay does little to improve soils already high in silt, clay, and very fine sand. Golf course topdressing sands containing at least 60% in the medium and fine category are acceptable for topdressing sport fields. Avoid using sands high in the fine and very fine range since they do not contribute to increasing macropore space.