Funding Agency: Northwest Center for Small Fruit Research
WSU Investigators: Pete W. Jacoby, Sindhuja Sankaran, Lav Khot, Markus Keller, and Troy Peters
Use of DRZ sub-surface drip irrigation has been evaluated over three growing seasons. This unique system does not involve the use of buried drip lines but, rather, delivers the drip irrigation through a pair of PVC delivery tubes inserted either side of the vine to a depth of 1-, 2-, or 3-foot depth. Our hypothesis was that considerably less water would be needed to maintain vines through the avoidance of water loss from surface evaporation and use by weeds. A primary concern was the ability of established vines to reallocate carbon resources to develop deeper root systems for accessing soil moisture delivered at depths below 18 inches where the bulk of roots have been reported when vines are supported by surface drip irrigation. Digital images obtained by rhizotron techniques have affirmed the capacity of vines to shift carbon resources for deep root development and these data are being prepared for publication. This project funding ended at the end of September 2017 and a final report is nearing completion to be submitted to the funding agency.