Submitted to: North American Strawberry Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: September 27, 1995
Publication Date: N/A
Interpretive Summary: Supplemental irrigation can increase strawberry yields, but there is no consensus on the best method to schedule irrigation. A plant-based technique to schedule irrigation would be useful and would eliminate the need to use costly soil moisture sensors and evaporation measuring devices. We found that a plant response, which is called guttation, could be used to discriminate plants with a water status above and below a critical stress level. Guttation occurs as water droplets at tips of leaves and appears at night under conditions of high humidity, low transpiration, and adequate soil moisture. Plants were irrigated whenever guttation ceased, at weekly intervals to replace 80% of evaporative water loss, or when soil water suction at 6 in depth reached 0.3 bar. The water application amount was reduced 20% using the guttation criterion. Total yields and fruit size for irrigation treatments were similar, but significantly greater than in non-irrigated plots. This research showed that the presence or absence of guttation is a way of visualizing the soil water availability to strawberries and is a tool strawberry growers can use to decide where and when water should be applied. It also demonstrates that when plant response is linked to irrigation scheduling, water application can be reduced without affecting fruit yield or size.
'Tristar' strawberry plants were irrigated from July to October (1993) using the following criteria: soil water suction at 0.2 bar, absence of guttation, and pan evaporation replacement. Fruit were harvested from August to October in 1993 and in June 1994. Yields and berry size were greater in plots receiving supplemental irrigation than in non-irrigated plots. However, the method of scheduling irrigation had no effect on yield or fruit size. Water application volumes indicated that guttation plots received about 20% less water than other irrigated plots. Our results suggest that guttation is a crop water status sensor and, if used to schedule strawberry irrigation, can improve water use efficiency.