Influence of a Single Soil Surfactant Application on Potato Ridge Moisture Dynamics and Crop Yield in a Water Repellent Sandy Soil

Recent studies in the USA (e.g. Hopkins and Cook, 2005) show that single applications of a particular soil surfactant, IrrigAid Gold (Aquatrols), on potato (Solanum tuberosum L.) crop fields can lead to a more uniform wetting pattern in the potato ridges, higher soil water contents in the ridges during dry periods, a decrease in soil water repellency, and increased crop yields at harvesting. In order to investigate the use and efficacy of this particular co-formulation of surfactants (alkyl polyglycoside and ethylene oxide-propylene oxide EO/PO block copolymer) under different soil and climatic conditions in Europe, a detailed field experiment was carried out at the 'De Vredepeel' experimental farm of Wageningen University and Research Center (WUR) during the growing season of 2009. The potato variety used was 'Fontana'. Four treatments were used 1) a control with no soil surfactant treatment and no irrigation, 2) irrigation alone, 3) soil surfactant alone, and 4) irrigation plus soil surfactant. Soil samples were collected from multiple depths and evaluated for degree of soil water repellency (on field-moist samples), soil water content, and dry bulk density. At the end of the growing season, crop yield from the test plots was also evaluated looking at quality and weight. The single surfactant application significantly increased moisture uniformity in the potato ridges, reduced water repellency and resulted in significant positive differences in yield and quality. Results from this initial trial suggests that this particular surfactant may be an effective technology to optimize water use and crop yield and quality in potato ridges prone to soil water repellency.