Strawberry Establishment with Drip or Sprinkler Irrigation.

Strawberries are a major crop grown in Ventura County, California, with an annual value of $394 million in 2008.  Each September, 1.2 m-wide raised beds are constructed with two drip irrigation lines placed 5-10 cm deep and covered with polyethylene mulch. Bare-root transplants are placed in 10×1 cm holes through the plastic mulch and irrigated with overhead sprinklers for 5-8 weeks.  Sprinkler irrigation rapidly hydrates plants and leaches salts from the root zone, but most of the water runs off the mulch without reaching the plants. A field study conducted at Camarillo, CA in 2009 compared standard overhead sprinkler irrigation to either reduced sprinkler irrigation or drip-only irrigation with two different arrangements of four drip lines.  Water use was reduced 34% in drip-only treatments and 20% in the reduced sprinkler treatment compared to standard sprinkler irrigation.  Soil pore EC was generally greater in drip only treatments than in sprinkler irrigation treatments, ranging from 3.4-7.9 dS/m.  In drip-only plots, placement of four drip lines in planting rows on the bed surface reduced EC of soil 10-40%, compared to four buried tapes.  Strawberry mortality was less than 2% in all treatments, a level acceptable for commercial production.  Incidence of foliar strawberry pathogens was 75% less in drip and reduced sprinkler treatments compared to standard sprinkler treatment.  Plants in sprinkler treatment were 13-18% smaller but the most uniform in size.  Dry biomass of new leaves was similar among treatments, but new root biomass in reduced sprinkler and surface drip treatments was 26% and 51% greater, respectively, than with either standard sprinkler or buried drip irrigation.  Early fruit production was similar among treatments. These results suggest that reduced irrigation and precise water placement are adequate for strawberry establishment, provide substantial savings of water, and minimize runoff, a major benefit to the environment.