Skip row planting configuration shifts grain sorghum water use under dry conditions

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 0.76 m 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. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for com-munication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Direc-tor, Office of Civil Rights, 1400 Independence Avenue, SM., Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.