Research Project: Integrated Water and Nutrient Management Systems for Sustainable and High-Quality Production of Temperate Fruit and Nursery Crops

Location: Horticultural Crops Research Unit

Project Number: 2072-21000-053-000-D
Project Type: In-House Appropriated

Start Date: Dec 18, 2018
End Date: Apr 13, 2020

Objective:
Objective 1. Determine the water and nutrient requirements needed to produce highquality temperate fruit and nursery crops in the Pacific Northwest. • Sub-objective 1.1. Develop water and nutrient guidelines to improve fruit and wine quality in Pinot noir. • Sub-objective 1.2. Characterize the interactions between water and nutrient use efficiency and plant quality in container-grown nursery plants. • Sub-objective 1.3. Identify salinity thresholds associated with compost and fertilizer use in highbush blueberry and basil. • Sub-objective 1.4. Determine temperature thresholds for sprinkler frost protection in cranberry. Objective 2. Evaluate the impact of soil microbes on crop water and nutrient use in grape and other specialty crop production systems. • Sub-objective 2.1. Characterize taxonomic and functional diversity of indigenous arbuscular mycorrhizal fungi (AMF) in vineyards. • Sub-objective 2.2. Determine the effects of AMF on interactions among plant development, resource allocation, and product quality in specialty crops. Objective 3. Develop irrigation and nutrient management practices and strategies that enhance crop productivity and quality with efficient use of water and fertilizers in berry and woody nursery crop production systems. • Sub-objective 3.1. Identify cover crop practices that enhance vineyard establishment and improve fruit quality in cool-climate wine grapes. • Sub-objective 3.2. Evaluate the potential benefits of using organic mulches under weed mat and identify the right source(s), time (fall vs. spring), and place (surface vs. incorporation) for organic compost application in highbush blueberry. • Sub-objective 3.3. Develop irrigation practices to reduce heat-related fruit damage in highbush blueberry. • Sub-objective 3.4. Develop nutrient management methods to increase cold tolerance in container-grown nursery crops.

Approach:
Experiments will be conducted in the greenhouse and field on small fruit and nursery crops, including Pinot noir wine grape, highbush blueberry, cranberry, and container-grown Rhododendron, Vaccinium, Salix, Euonymous, floral geophytes (e.g., lily), and basil. For objective 1, relationships among soil N, P, and K availability, vine growth, and fruit quality will be determined in wine grape and used to develop leaf and petiole nutrient standards for production of Pinot noir and cool-climate cultivars in the Pacific Northwest. The extent to which berry quality of Pinot noir is altered by soil water deficits will also be investigated to provide benchmarks that relate specific indicators of vine water status such as leaf water potential and stomatal conductance to fruit quality. Greenhouse studies will be designed to test whether excess N availability reduces plant quality and water use efficiency in container-grown nursery plants and to identify salinity levels that limit shoot and root growth and function and lead to leaf necrosis in blueberry and basil. Critical temperatures for freeze damage in the region will be likewise determined for cranberry using combination of laboratory measurements on excised plant tissues and temperature-control units on the plants in the field. For objective 2, root and soil samples will be collected from plants grown in both field and greenhouse experiments to test if diversity of arbuscular mycorrhizal fungi (AMF) is a function of sampling location, soil depth, and cover crop use in grape roots; and to ascertain whether AMF improve quality of floral geophytes by enhancing P uptake and allocation. For objective 3, field studies will be designed to determine whether alleyway cover crops and residue placement in vine rows increases root production, AMF colonization, and plant growth and nutrient uptake in young grapevines; if using organic mulches (sawdust or compost) under weed mat will enhance soil conditions, including availability of water and nutrients, and result in more growth and production in highbush blueberry; and whether overhead cooling with sprinklers or misters reduce heat damage in blueberry fruit when applied correctly at the proper temperature, rate, and frequency. Can-yard studies will likewise be designed to test whether increased N availability reduces cold tolerance or, alternatively, if application of cation fertilizers (K, Ca, Mg) increase cold tolerance in container-grown nursery plants. Measurements in the studies will include standard techniques for measuring plant water status (pressure chamber, porometer), photosynthesis (gas-exchange), photosynthetic efficiency (fluorometer), fruit quality (refractometry, acid titratation, colorimetry, HPLC), root production and turnover (minirhizotrons, soil cores), mycorrhizal colonization (microscopy), DNA sequencing (PCR), soil pH and EC, soil water content (TDR, tensiometers), and plant and soil nutrients (CNS analyzer, ICP). Data will be analyzed using ANOVA, ANCOVA, nonparametric, and regression techniques. In some cases, studies may need to be repeated due to poor weather conditions or the need for a wider range of treatments.