Effect of Planting Cotton in Solid and Single-skip Row Configurations on Yield and Soil Water Use

Australian growers plant crops using different skip row configurations to minimize production risk in water-limiting environments. Previous studies have focused on comparing the effect of row configuration on crop yield, and information on soil water is still lacking. The objective of this study was to compare the water use, soil water extraction, and yield of dryland cotton (Gossypium hirsutum L.) planted using solid and single-skip row configurations. An experiment comparing two row configuration treatments (solid and single-skip) was conducted in a cotton field with heavy-clay soil in the sub-tropical climatic environment of Queensland, Australia, during 2007-2008. Water content in the soil profile was measured about weekly using the neutron probe method. Measurements were taken from three positions from the crop row: within a row (P1), between two rows (P2), and skip or planted row (P3). The soil water measurements indicated that, in general, the solid treatment tended to extract more water from shallower depths earlier in the growing season. The single-skip treatment resulted in taller plants, which extracted more water from deeper in the soil profile later in the season. For the entire season, however, both treatments used around the same amount of soil water (128 mm), suggesting that both treatments were water-limited and used all the water available to the crop. The 128 mm added to the seasonal rainfall of 271 mm allowed us to estimate the seasonal crop water use at about 399 mm, which was around half of the seasonal grass-reference evapotranspiration (ETo = 804 mm) for the site. The lint yield was statistically the same for both treatments, although the taller plants from the single-skip treatment tended to have a greater yield per plant (but not significantly different). The estimated water use efficiency (WUE) for the solid and single-skip configuration were 3.5 and 3.3 kg lint/ha/mm water use, respectively.