Effect of skip row planting configuration on grain sorghum water use

Authors: Nielsen, David; Vigil, Merle; HENRY, BRIAN - Mississippi State University

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2018
Publication Date: 4/13/2018
Citation: Nielsen, D.C., Vigil, M.F., Henry, B.W. 2018. Effect of skip row planting configuration on grain sorghum water use. Field Crops Research. 223:67-74. https://doi.org/10.1016/j.fcr.2018.04.003.
DOI: https://doi.org/10.1016/j.fcr.2018.04.003

Interpretive Summary: Growing crops in a skip row configuration has been proposed and tested as a means of increasing crop yields under water stress conditions. Two of those configurations are designated as plant-one-skip-one (P1S1) in which every other row is planted or plant-two-skip-two (P2S2) in which two rows, 30" apart, are planted and then two rows are skipped (leaving a 90" gap between pairs of planted rows). No soil water data has been previously published to verify the extent to which roots of grain sorghum actually extract water from the inter-row spaces in skip row planting configurations or to verify whether the hypothesized shifting of water use from the vegetative growth stage to the reproductive and grain-filling growth stages actually occurs with skip row. This 3-yr study found that grain sorghum grown at Akron, CO, extracted water at distances of 45" from the planted row. During dry growing seasons, skip row planting shifted the water use such that greater water use was seen during the second half of the growing season than with the conventionally spaced planting. These results support the observation of greater sorghum yields with skip row planting than with conventional 30" row spacing during dry growing seasons.

Technical Abstract: Grain sorghum (Sorghum bicolor L. [Moench]) is grown as a dryland crop in the semi-arid Central Great Plains. Growing the crop in a skip row configuration has been proposed as a means of delaying water use during the vegetative stage such that more water will be available to be used during the more critical flowering and grain filling stages, thereby improving yield under water stress conditions. The objective of this study was to determine if grain sorghum grown in a skip row configuration used water differently than sorghum grown in conventionally spaced rows. Grain sorghum was grown for three years at Akron, CO in three planting configurations: conventionally spaced rows 0.76m apart, one row planted and one row skipped (P1S1), and two rows planted and two rows skipped (P2S2). Each planting configuration was planted at two seeding rates. Soil water was measured at several distances from the planted row at planting, flowering, and physiological maturity. Soil water depletion and water use were not affected by seeding rate. Grain sorghum was found to extract water at distances of 114 cm from the planted row. When growing season conditions were dry and starting soil water contents were low, skip row planting shifted the water use such that greater water use was seen during the second half of the growing season than with the conventionally spaced planting. These results support the observation of greater sorghum yields with skip row planting than with conventional row spacing during dry growing seasons.