Issue No. 6, Article 11/May 5, 2006
Remember the Rotary Hoe?
Corn planting has progressed rapidly in many areas of Illinois, aided by soil conditions conducive for planting (i.e., dry). While dry soils often speed planting operations, the level of weed control provided by soil-applied herbicides is often adversely impacted by dry conditions. Most soil-applied herbicides, when applied to the soil surface with no subsequent mechanical incorporation, require 0.5 to 1 inch of precipitation within 7 to 10 days after application to be adequately moved into the soil and available for uptake. If little or no precipitation has been received since herbicide application, weed escapes may soon become evident.
For those fields that haven't received much precipitation since preemergence herbicides were applied, a rotary hoe may help with weed control. Rotary hoeing is most effective while weeds are still in the "white" stage, following seed germination but prior to plant emergence. Once weed seedlings have emerged, the effectiveness of rotary hoeing is diminished since the plant's rapidly developing root system helps anchor the plant. Hoeing is generally most effective when done at speeds of 8 to 12 miles per hour. A second rotary hoeing 7 to 10 days after the first might provide improved weed control. Hoeing may also aid crop emergence by breaking soil crusts that can develop after planting.--Aaron Hager