Location: Horticultural Crops Production and Genetic Improvement Research Unit
Project Number: 2072-30500-002-000-D
Project Type: In-House Appropriated
Start Date: Apr 14, 2025
End Date: Apr 13, 2030
Objective:
The Pacific Northwest (PNW) produces more than half of the blueberries in the United States and nearly 100% of the nation’s processed raspberries and blackberries. To remain competitive globally, producers of these crops must be efficient in their use of soil, water, and nutrient resources. The goal of this project is to develop new approaches that integrate water and nutrient management methods within local environmental and cultural constraints to improve the quantity and quality of berry crops grown in the PNW.
Objective 1: Adapt and create strategies to best manage resources to improve production, quality, profitability, and sustainability of berry crops, with an emphasis on remote sensing to monitor and manage water, nutrients, and soil.
Sub-objective 1.A: Develop crop coefficients for calculating irrigation water requirements in new and fully productive fields of northern highbush blueberry.
Sub-objective 1.B: Evaluate the effects of post-harvest deficit irrigation on water use, fruit quality, and cold hardiness of trailing blackberry.
Sub-objective 1.C: Ascertain the suitability of evaporative cooling and other horticultural technologies for mitigating heat damage in red raspberries.
Sub-objective 1.D: Identify fertilizer methods for increasing calcium content and fruit quality of raspberries and blackberries.
Sub-objective 1.E: Assess the practicality of utilizing nutrient water recovered from liquid dairy waste to fertigate blueberries produced in soilless media.
Approach:
For Sub-objective 1.A, we will test the hypothesis that crop coefficients differ among cultivars and are linear functions of canopy development. We installed large weighing lysimeters to measure crop water use in early, mid-, and late-season cultivars that cover the range in which most blueberries ripen in the PNW. If the weighing lysimeters fail, we will rely on robust percolation lysimeters installed at the site to calculate crop water use and develop crop coefficients for the given cultivar. For Sub-objective 1.B, we will test the hypothesis that withholding irrigation after harvest reduces winter injury but has no effect on yield or fruit quality in blackberry. Treatments will be initiated in a mature field and applied for at least two growing seasons. Additional field sites will be monitored if pests or environmental extremes damage the crop and prohibit us from collecting data. For Sub-objective 1.C, we will test the hypothesis that evaporative cooling with microsprinklers is a reliable and cost-effective means of preventing heat damage and improving fruit quality in raspberries. Three treatments, including evaporative cooling with micro-sprinklers, photo-selective shade cloth, and an untreated control will be applied to a field planted with two commercial cultivars, ‘Meeker’ and ‘Wakefield’, and two advanced selections developed by the USDA and Washington State University breeding programs. If evaporative cooling or shade netting proves ineffective or too costly, additional experiments will be conducted to test the efficacy of commercially available reflective kaolin-based particle films and biostimulants at mitigating heat and UV damage in the fruit. For Sub-objective 1.D, we will test the hypothesis that fertigation increases availability and uptake of calcium during early fruit development of raspberries and blackberries. Treatments will be applied to commercial fields in Washington and Oregon and include soil applications of lime or gypsum; foliar applications of calcium chloride or a comparable certified organic formula; fertigation with soluble calcium fertilizers; and an untreated control. Higher rates or alternate fertilizers will be tested if none of the treatments have an impact on yield, fruit quality, or nutrients in the plants. For Sub-objective 1.E, we will test the hypothesis that growth and production of blueberry plants cultivated with recovered nutrients and water from a novel hybrid electrodialysis (ED) – forward osmosis (FO) process will be comparable to those cultivated with chemical fertilizers. The plants will be grown in 25-L pots filled with soilless media and fertigated through a drip irrigation system with ED-FO product water recovered from liquid dairy waste, original liquid digestate, or a conventional fertilizer solution (control). If the plants fail to grow or produce fruit with the product water, we will modify the process and attempt to produce a more suitable nutrient solution for blueberries. Measurements and techniques used in these studies will include standard approaches to measure plant growth, yield, fruit quality, plant and soil nutrients, and insects and pathogens in the plants and fruit.
