Published online by Cambridge University Press: 12 June 2017
This 4-yr experiment was conducted to develop a profitable conservation tillage system for dryland and furrow-irrigated cotton in a winter wheat-fallow-cotton cropping system at Etter, TX. In the 2-yr cropping sequence, winter wheat was planted immediately after cotton harvest in mid-November and furrow irrigated. Three residual herbicide treatment combinations with atrazine or propazine with fluometuron, or propazine alone were sprayed on stubble after wheat harvest in late June and compared to repeated applications of glyphosate and conventional disk tillage. Glyphosate was used to control weeds that escaped residual herbicides. The following March, fluometuron, prometryn, and 2,4-D were sprayed on no-tillage treatments and trifluralin was incorporated with conventional planting. Hoeing cost ha-1 to control Palmer amaranth and kochia averaged about $13 where trifluralin was used, $38 when initial treatment included fluometuron, $63 with propazine, and $93 when glyphosate alone was used to control weeds in fallow. Lint yield on dryland was about 390 kg ha-1 with disking and when glyphosate was followed by disking in spring, and 540 kg ha-1 with no-tillage. With irrigation, lint yield was 660 kg ha-1 with disking and 759 kg ha-1 with the best no-tillage treatment. Long-term profits ha-1 on dryland ranged from $340 for disking to $524 for propazine no-tillage. With irrigation, profit ha-1 ranged from $707 for disking alone to $751 when glyphosate was used after wheat harvest and followed by disking and incorporation of trifluralin the next spring before planting cotton.