ESTIMATING THE NET RETURNS OF MANAGING PIGWEED IN COTTON

The use of a winter cover crop in cotton production is an important part of a conservation tillage system, along with a cost effective weed management program. A study was established in the fall of 2006 to determine the effect of management practices and herbicide treatments on net returns in two different locations in Alabama. The experiment included horizontal strips consisting of four conservation-tillage treatments with differing cover crop planting dates, a conservation tillage/winter fallow treatment, and a conventional tillage treatment with no cover crop. There were four herbicide regimes: 1) a broadcast preemergence (PRE) herbicide followed by a postemergence (POST) followed by a LAYBY application, 2) a banded PRE application followed by a POST application followed by a LAYBY application, 3) a POST herbicide followed by a LAYBY application, and 4) a LAYBY application. Net returns were lower for the LAYBY only herbicide treatment and were generally highest for the POST and LAYBY herbicide treatment. The use of conservation tillage with an early planted winter cover crop had higher net returns than the conventional tillage system in two of the three years. The addition of PRE and POST applications of herbicides significantly increased the net returns (P ≤ 0.05) as compared to a LAYBY treatment alone.