Cotton subsurface drip and overhead irrigation efficiency, maturity, yield, and quality
Subsurface drip (SSD) is used as a water-efficient alternative to overhead irrigation in many crops. This study compared soil water, water use, crop maturity, lint yield, and fiber quality of cotton (Gossypium hirsutum L.) grown with SSD to cotton grown with overhead irrigation. Three experiments were conducted at two Georgia locations in 2004 and 2005. Treatments consisted of overhead irrigated, nonirrigated, SSD matched to overhead irrigation rates (SSD Matched), and SSD based on soil water (SSD Fed). Cotton maturity was affected by irrigation treatment as nonirrigated cotton matured earliest, whereas overhead irrigated cotton matured latest. Subsurface drip irrigated cotton produced similar or higher lint yields than overhead irrigated cotton. Subsurface drip provided adequate soil water and irrigation amounts were 4.4, 8.2, and 0.5 cm less than overhead irrigation at the three locations. Water use efficiency (WUE) of cotton SSD irrigated was 23 and 15% higher than overhead-irrigated cotton in two experiments. Irrigation method did not substantially affect fiber quality; however, micronaire was higher in cotton from the SSD Fed treatment than cotton in the Overhead treatment in two locations. We conclude that SSD irrigation provides the same positive effects as overhead irrigation in cotton production while reducing irrigation water use and may allow for improved irrigation efficiency.