Cotton (Gossypium hirsutum L.) producers interested in adopting winter cover crops need information about profit maximizing N fertilization rates. This study evaluated how alternative winter covers affect profit maximizing N rates and net revenues for tillage and no-tillage cotton. Data from a long-term experiment in Tennessee were used to estimate N response functions for tillage and notillage cotton following winter wheat (Triticum aestivum L.), hairy vetch (Vicia villosa L.), crimson clover (Trifolium incarnatum L.), and no cover. The response functions were used to predict profitmaximizing N rates and net revenues. Several important findings resulted. First, cotton following vetch requires no N fertilization to maximize profit. Conventional-tillage cotton following vetch requires 62 kg ha-1 less N fertilizer to maximize profit than cotton following no cover. No-tillage cotton following vetch needs 76 kg ha-1 less applied N to maximize profit when compared with no cover. Second, vetch provides profit-maximizing yields similar to cotton with no winter cover. Finally, even with the substantial reduction in fertilizer cost, maximum net revenues are smaller for vetch than for no cover, primarily due to the cost of establishing the vetch cover. However, a small reduction in the price of vetch seed or a small increase in lint yields from those estimated would make no-tillage cotton following vetch profitable relative to no cover.
