Location: Horticultural Crops Research UnitTitle: Irrigation and fertigation with drip and alternative micro irrigation systems in northern highbush blueberry
|VARGAS, OSCAR - OREGON STATE UNIVERSITY|
|STRIK, BERNADINE - OREGON STATE UNIVERSITY|
|SUN, LUNA - OREGON STATE UNIVERSITY|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/2/2015
Publication Date: 6/30/2015
Citation: Vargas, O., Bryla, D.R., Weiland, G.E., Strik, B.C., Sun, L. 2015. Irrigation and fertigation with drip and alternative micro irrigation systems in northern highbush blueberry. HortScience. 50(6):897-903.
Interpretive Summary: Fertigation, the application of fertilizers to plants through an irrigation system, is becoming a common practice in many crops worldwide, including highbush blueberry. The objective of the present study was to determine the effects of nitrogen fertigation using a conventional drip configuration (two laterals per row) and alternative micro irrigation systems, including a geotextile irrigation system and microsprinklers, on shoot growth and early fruit production. Six blueberry cultivars were evaluated with each system. Many new plantings are irrigated by drip, particularly in newer growing regions such as California, eastern Oregon, and Washington. Recently, several manufacturers began developing modified drip products such as geotextile irrigation systems to deliver a broad band source of water and nutrients to the plants rather than point sources produced by standard drip systems. Microsprinklers are not commonly used in blueberry but are becoming a popular choice for irrigating plants grown on pine bark substrate. Blueberry establishment and yield was most efficient when the plants were fertigated by drip. While geotextile tape was also effective, particularly during the first year after planting, it was more costly and produced more-or-less the same amount growth and yield as drip the following two years. Fertigation with microsprinklers, on the other hand, reduced yield and berry quality (salt stains on berries) in each cultivar and resulted in much lower N efficiency than the other treatments. The results of the study provides useful information for improving growth and early fruit production in highbush blueberry.
Technical Abstract: The effects of nitrogen (N) fertigation using conventional drip and alternative micro irrigation systems were evaluated in six cultivars of northern highbush blueberry. The drip system consisted of two laterals of drip tubing, with 2 L/h in-line emitters (point source) spaced every 0.45 m, on each side of the row at a distance of 0.2 m from the base of the plants. The alternative systems included a geotextile irrigation system and microsprinklers. The geotextile irrigation system was comprised of a single lateral of drip tape covered with geotextile fabric that dispersed water and nutrients along the entire length (broad band source); the lateral was located along the row near the base of plants. The microsprinkler system included hanging fan-jet emitters located between every other plant at a height of 1.2 m (full coverage). Liquid urea was injected weekly each spring and summer at annual rates of 100 and 200 kg/ha N by drip, 200 kg/ha N by geotextile tape, and 280 kg/ha N by microsprinklers. In year 1, plant size was greatest in plants fertigated by geotextile tape and smallest in those fertigated by drip at the lower N rate or microsprinklers. The following year, plant size was greatest in plants fertigated by drip at the high N rate, similar between drip at the low N rate and geotextile tape, and smallest between plants fertigated by microsprinklers. By year 3, the first year in which the plants were cropped, yield averaged 3.1 t/ha in ‘Earliblue’, 5.5-5.6 t/ha in ‘Duke’ and ‘Draper’, 7.1 t/ha in ‘Bluecrop’, 9.1 t/ha in ‘Elliott’, and 6.4 t/ha in ‘Aurora’; however, yield was similar among the drip (both N rates) and geotextile tape treatments and only less with microsprinklers. Overall, plant establishment was similar between plants fertigated by drip and geotextile tape, and 100 kg/ha N by drip was sufficient to maximize early fruit production. Fertigation with microsprinklers, on the other hand, produced less growth and yield than the other treatments and resulted in white salt deposits on the fruit.