Water table level management as an irrigation strategy for cranberry (Vaccinium macrocarpon aiton)

Abstract

Cranberry production is a water intensive practice that requires irrigation during summer months to achieve maximum yields. Previous studies have found that root zone tension maintained between -4 and -7.5 kPa allows for maximum yields without over irrigating. The present study looks at the effects of managing a water table to supplement overhead sprinkler irrigation with upward flow. Two drainage systems, controlled and free, were implemented in a cranberry bed constructed of fine sand. The controlled drainage system used existing drain tiles and a sump to maintain an artificial water table, while the free drainage system had no manipulation of the water table. Daily upward flow and water table level were measured in four locations, across the length of the bed, for each drainage system. Comparing upward flow with evapotranspiration (ET) rates, approximately 30% of maximum daily ET can be met by holding a water table between 500 and 600 mm. Numerical simulations indicate that water tables shallower than 500 mm allow for nearly full supply of ET, but at root zone soil water tensions too wet for the best productivity. Field results and model simulations indicate that water table management can be a useful tool in cranberry irrigation.