Broadcast or Banded Atrazine + Propachlor with Tillage Variables in Grain Sorghum1
- R. S. Moomaw and
- L. R. Robison2
Application of a herbicide to the least possible soil surface area consistent with adequate weed control in a given crop production system may be desirable because costs are reduced and less chemical is added to the environment. Data have not been available to indicate the minimum herbicide band width that could be used in combination with mechanical tillage in grain sorghum [Sorghum bicolor (L.) Moench] production. The herbicide mixture 2-chloro-4(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) + 2-chloro-N-isopropylacetanilide (propachlor) was applied preemergence broadcast and in herbicide band widths of 18, 36, and 53-cm to grain sorghum. All herbicide treatments were applied as 1.1 kg atrazine + 2.7 kg propachlor per treated hectare. One row-middle cultivation and one rotary hoeing were also imposed on the herbicide treatments as variables. The 18-cm band of atrazine + propachlor with supplementary row-middle cultivation was as effective in controlling weed growth and maintaining grain yield as were wider herbicide bands or a broadcast treatment. Broadcast herbicide-treated sorghum without cultivation yielded as well as the handweeded treatment both years of the experiment. Cultivation reduced average weed growth 73%. Cultivator effectiveness on an 18-cm herbicide band equalled that measured on wider herbicide bands. Rotary hoeing significantly reduced weed growth and increased average grain yields 10% on herbicide-treated plots. The average ratio of weed dry weight to reduction in grain sorghum yield was 1.3 to 1.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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