Shallow Subsurface Drip Irrigation (S3DI) for Small Irregular-shaped Fields in the Southeast

Abstract

Field tests were conducted using S3DI on cotton (Gossypium hirsutum, L.), corn (Zea mays, L.), and peanut (Arachis hypogeae, L.) rotations to investigate yield potential and economic sustainability of this irrigation system. Drip tubing was installed in alternate row middles, strip tillage was used prior to planting, and tubing was removed prior to peanut harvest. This system was used for two drip tube installation cycles or six years (2003 to 2008 inclusive). This S3DI system cost about $420 ha-1 for the tubing and a flexible hose mainline. Nonirrigated crop yields were equal to irrigated yields when adequate precipitation was received during the growing season. Installing S3DI increased crop yield five out of six years compared with nonirrigation. Irrigated gross and net revenue increased four out of six years compared with nonirrigation. Net income divergence between irrigated and nonirrigated systems increased in drought years and decreased in higher precipitation years. Total irrigated net revenue over six years was almost double ($6358 ha-1) compared with nonirrigated net revenue ($3700 ha-1). Drip tubing repair expense for 2003 to 2006 was just over $8 ha-1 yr-1. There was very little biological damage during the 6-yr sequence. Mechanical damage was the major cause of tubing failure due to the lack of an electronic guidance system. The expense of the S3DI system described here does not include tube installation or extraction, fuel/energy, system maintenance, irrigation pump, and other conveyance expenses. More research is needed when using S3DI in various growing areas, crops, and management styles.