Effective nitrogen management is more important for cotton than for most other major field crops; however, little information is available regarding the effects of narrow row spacing on cotton N requirements. A study was conducted to evaluate the effects of four nitrogen rates (0, 50, 100, 150 lbs N per acre) and two row spacings (19 and 39 inches) on cotton growth and production. Both row spacing and N rate significantly affected plant height. From peak bloom through maturity, plants in 19-inch rows were significantly shorter compared to those in 38-inch rows. Petiole nitrate concentrations increased consistently with increasing N rate regardless of row spacing. However, plants in conventional rows bad significantly greater nitrate concentrations compared to UNR plants across N treatments. Averaged across N rates, the 19-inch UNR row spacing significantly increased lint yields producing 1,089 lbs lint/acre compared to 865 lbs lint/acre for conventional 38-inch row spacings. Consistent with previous results, plant mapping data showed that UNR plants set a higher percentage of bolls on fruiting branches 1 through 5 compared to plants in conventional row spacings. In addition, increasing N rate tended to shift boll retention to higher positions, regardless of row spacing.
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