Location: Horticultural Crops Research2012 Annual Report
1a. Objectives (from AD-416):
Objective 1: Determine nutrient requirements to enhance product quality in woody perennial crops such as grapevine and rhododendron. Objective 2: Characterize the role of mycorrhizal taxonomic diversity and identify important root-mycorrhizal interactions in cropping systems. Objective 3: Enhance product quality by optimizing crop management practices that promote overall root function to satisfy nutrient requirements in woody perennial crops. Objective 4: Integrate new and existing small fruit cultivars into efficient, environmentally accepatble production systems.
1b. Approach (from AD-416):
Determine the relationships between nutrient uptake, plant performance, and fruit quality of Pinor noir grapevines. Characterize the interactions between N use efficiency and plant quality and performance in container-grown nursery plants. Characterize the role of taxonomic and functional diversity of mycorrhizal fungi in grapevine cropping systems. Determine the interactions between plant resource allocation patterns, plant development, and production quality of geophyte nursery crops as affected by mycorrhizal fungi. Determine optimal methods for water application to improve efficiency of nutrient use and plant performance of grapevines and container-grown ericaceous plants. Characterize the influence of management practices on mycorrhizal fungi wthin winegrape and nursery crop production systems.
3. Progress Report:
We are conducting on-going studies to determine how various nutrients alter plant physiology and function and how nutrient availability influences fertilizer requirements and end-product quality of container-grown nursery plants and field-grown grapevines and berry crops. This information will be used to optimize nutrient management strategies, including proper source, rate, timing, and placement of fertilizers, for maximum plant response with minimal impact to the soil and water resources. Interactions between plants and mycorrhizal fungi alter the physiology and nutrient uptake of small fruit and nursery crops, but plant benefits from symbiotic fungi such as mycorrhizas are a function of fungal diversity, plant growth habit, and soil conditions. We are investigating how resource allocation patterns altered by mycorrhizal associations influence product quality and determine whether the effects of the symbiont on plant nutrition result in significant impacts on product quality. Additionally, we are assessing how the mycorrhizal fungi alter end-product quality (polyphenolic profiles) of medicinal and culinary herbs and whether they can decrease nutrient run-off from container production systems. We are also assessing how various management practices (cover crops, irrigation, and tillage) influence mycorrhizal fungi and root function and nutrient use. This information will be used to determine how benefits from the fungi can be enhanced to increase production efficiency and product quality in nursery crops and vineyards. In cooperation with researchers at Oregon State University, we examined production systems for establishing organic blueberries, including different combinations of planting systems, mulch, and fertilizers, and identified practices with greatest economic benefit. We also identified key physical and chemical traits needed to develop custom compost for blueberry. The information is assisting potential and existing organic blueberry growers with production decisions to improve profits and increase efficiency of farming operations. Research results will be used as a basis for evaluating different management practices and integrating these practices with those currently used in production systems. Information on plant nutrition is being used to develop nutritional guidelines based on the combined effects of nutrient and water management on end-product qualities, including composition and performance. Information on mycorrhizal fungi will be used as a basis for evaluating how host physiology and management practices alter symbiotic performance and to develop sustainable practices that optimize product quality while maximizing benefits from mycorrhizal symbionts.
1. Enhanced basil phenolic composition with mycorrhizal fungi (AMF) and phosphorus (P) availability. Quality of basil used in fresh and dry products is a function of its production of secondary metabolites, including phenolics. Phenolics are involved in several plant responses to biotic and abiotic stimuli and have potential human health benefits. ARS scientists in Corvallis, OR, and Parma, ID, determined that AMF and P availability in the growing substrate can be used to alter phenolic profiles in four basil cultivars. Production of many phenolic compounds were related to the effects of P-availability and AMF on plant nutrient status; however, P availability and AMF differentially enhanced production of specific phenolic compounds and resulted in plants with different phenolic profiles. Results indicate fertilizer management can be used to alter phenolic composition of basil, and AMF inoculation may provide an additional strategy for optimizing basil compositional quality.
2. Altered plant form and nutrient composition of container-grown plants with irrigation management in the nursery. End-product quality of perennial nursery plants depends on environmental conditions (e.g., water and nutrients) that optimizes plant growth and storage of reserves. Negative growth responses to high fertilizer application rates may be related to increased water stress in containers. ARS scientists at Corvallis, OR, in collaboration with Oregon State University and Mississippi State University determined that low irrigation frequency and high rates of nitrogen (N) fertilizer application during container production of three Rhododendron cultivars can cause transient increases in plant water stress. Greater water stress altered plant form and decreased nutrient uptake and nutrient use without detectable changes in total plant biomass. These results demonstrate that high rates of N fertilizer during container production increase plant water stress and the effects of water stress on nutrient reserves have the potential to impact growth during the following growing season.
3. Altered landscape performance of container-grown plants with water stress in the nursery. Nursery production practices for container-grown plants attempt to provide an environment that optimizes plant growth and storage of reserves related to promoting growth after transplanting, and may be planted in less than optimal growing environments in the landscape. ARS scientists at Corvallis, OR, in collaboration with Oregon State University and Mississippi State University determined that early season performance of three Rhododendron cultivars in the landscape was related to how irrigation frequency and N availability alters water stress, nutrient uptake, and allocation during container production and responses of deciduous and evergreen cultivars after transplanting differed. Greater water stress in containers increased nutrient reserves and allocation to roots and enhanced growth but not flowering in the landscape in a deciduous cultivar and enhanced flowering but not growth in evergreen cultivars in the landscape. These results demonstrate that water stress in container production may be a useful strategy to improve landscape performance of container-grown plants and that cultivar differences in response to water stress are related to differences in competition between vegetative and reproductive growth for resources after transplanting.
4. Ring nematode reduces grapevine carbohydrate reserves. Management of existing vineyards with high populations of the ring nematode requires better knowledge of whole-plant response to nematode parasitism. ARS researchers in Corvallis, OR, found that ring nematode had more impact on carbohydrate reserves in vines than on mineral nutrient reserves. Furthermore, vines grown under low light (15% sunlight) conditions suffered greater damage due to higher nematode numbers per mass of roots than did plants grown in full sun or those defoliated by 75%. Viticultural practices to increase carbohydrate reserves in the vine and roots such as lower crop loads or earlier harvesting of fruit for sparkling wine are recommended to reduce the impact of ring nematode on vine productivity and survival.
5. Grapevine rootstock resistance to ring nematode. Identifying rootstocks that are resistant to ring nematode is an important tool for managing this pest in vineyards. Rootstock resistance to ring nematode breaks down after exposure to the pest for three years. ARS researchers in Corvallis, OR, showed that only one rootstock (420A) out of three previously identified as resistant to ring nematode in greenhouse trials remained resistant after four years in field microplots. Based on these findings, only rootstock 420A is recommended for use at sites in western Oregon with ring nematode.
6. Fertilizer requirements of highbush blueberry during field establishment. ARS researchers at Corvallis, OR, have generated the first comprehensive nutrient accumulation data set from planting to fruit harvest for establishing highbush blueberry. The information was used to determine nutrient requirements of the young plants, a useful tool for developing efficient fertilizer management practices during the critical stage of field establishment. Plant uptake of most nutrients increased throughout the growing season, indicating that it is best to apply the majority of fertilizers in the spring; however, potassium, magnesium, manganese, and zinc uptake was higher later in the season and therefore it may be better to apply these nutrients, if needed, in early or midsummer. The information has been transferred to growers and is currently included as part of the nutrient management guidelines used in the Pacific Northwest.
7. Benefits of nitrogen fertigation in blueberry. A major benefit of drip irrigation is the ability to apply fertilizers through the irrigation system, a process referred to as fertigation. Fertilizer guidelines for many crops, however, are based on granular fertilizer application. ARS researchers at Corvallis, OR, with the University of Evora, Portugal, determined that fertigation with nitrogen fertilizer enhanced early growth and reduced the risk of salt injury often associated with use of conventional granular fertilizers in blueberry. The information will be used to develop new guidelines on efficient nitrogen management by fertigation to increase production and reduce fertilizer waste in blueberry.
Schreiner, R.P., Pinkerton, J., Zasada, I.A. 2012. Delayed response to ring nematode (Mesocriconema xenoplax) feeding on grape roots linked to vine carbohydrate reserves and nematode feeding pressure. Soil Biology and Biochemistry. 45:89-97.