Impact of Varying Planting Dates and Tillage Systems On Cotton Growth and Lint Yield Production.

As economic conditions deteriorated, cotton (Gossypium hirsutum L.) producers have looked to improve profit margins by reducing inputs while maintaining yields.  Pairing the yield benefits from early planting with the input reductions from conservation tillage might help accomplish those goals.  The objective was to determine how growth, lint yield, and fiber quality were impacted by planting cotton early while using minimum tillage.  Four cotton cultivars were planted either during the first week in April (Early) or the first week in May (Normal) in 2004-2007.  Half the plots were conventional tillage and half were minimum tillage.  Dry matter partitioning, flowering, root hydraulic conductance, leaf water potential, lint yield, yield components, and fiber quality data were collected.  Cultivars differed in leaf water potential, leaf osmotic potential, and root hydraulic conductance.  Root hydraulic conductance for the early planting was 21% greater than the normal planting, but no differences were detected between tillage treatments.  Early planting increased yields 22% in 2007, but yields did not differ between planting dates any other year.  During 2006 and 2007, lint yields were reduced 13% when minimum tillage was employed.  No planting date*tillage treatment interactions were detected, so the same response to minimum tillage could be expected regardless of whether the planting occurred in early April or early May.  Even though yield reductions were occasionally observed with minimum tillage, the pairing of minimum tillage with early planting could be a viable option for producers because of the input reduction.