Grain sorghum water use with skip-row configuration in the central Great Plains of the USA

Grain sorghum (Sorghum bicolor (L.) Moench) is commonly produced under conditions where soil water deficits frequently occur. Research was conducted at ten (10) site-years from 2005 to 2007 across Nebraska where annual mean precipitation ranges from 350 to 900 mm year ^-1 to determine the effect of row configuration and plant population on soil water distribution, water extraction patterns, crop water use, and water use efficiency (WUE). Three row configurations including all rows planted (s0), alternate rows planted (s1), and two rows planted alternated and two rows skipped (s2) were evaluated in a complete factorial with two populations. Soil water content was measured to 1200 mm depth biweekly with a neutron moisture meter. Total growing-season precipitation varied from 239 to 452 mm. Stored soil water at physiological maturity with the skip-row configurations were 10 to 35 mm greater than s0 across site-years. Water use efficiency was higher with skip-row configurations at site-years with mean growing-season precipitation < 2 mm day ^-1, and lower at site-years with mean growing-season daily precipitation > 2.5 mm. Skip-row planting conserves water for the reproductive stages and enhances WUE and yield when water deficits are relatively severe.