Row and Plant Spacing Effects on Growth and Yield of Dryland Cotton Where Growing Season Duration Is Limited

Cotton (Gossypium hirsutum L.) is a potentially profitable crop suited to dryland production, but the limited growing season duration and energy of the Texas Panhandle and southwestern Kansas may increase production risk by limiting boll maturation and yield. We hypothesized that cotton yield limited to the earlier set bolls could be counteracted by increasing plant population. Our objectives were to quantify (i) row width and (ii) plant spacing effects on the growth, yield, and fiber quality of dryland cotton. Field tests of row widths from 0.25 to 0.76 -m and in-row plant spacing of 0.075, 0.10, and 0.15 – m were conducted from 1999 to 2006 on a nearly level Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll) managed in a wheat (Triticum aestivum L.), cotton, fallow (W-Ctn-F) rotation. Drought conditions prevented crop establishment in 2002 and 2006, while a promising 2005 crop was destroyed by hail. The measured plant height and boll number at harvest in addition to lint yield increased significantly as the space between plants and rows increased during most years. This was not consistently the case for the two varieties evaluated. Our data show that planting cotton in narrow rows to increase plant population and the number of early bolls often reduced lint yield compared with plants grown in conventional 0.76m rows