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United States Department of Agriculture

Agricultural Research Service

Research Project: Determining Impact of Soil Environment and Root Function on Horticultural Crop Productivity and Quality

Location: Horticultural Crops Research

2011 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
This report documents progress for Project Number 5358-21000-042-00D, which began in March, 2011 and continues research from Project Number 5358-12210-003-00D, entitled "Factors Influencing Root Development, Physiology, and Productivity OF Horticultural Crops". In FY11, this project was reassigned from NP302 to NP305. Progress from the 0.5 years of this project is summarized below.

The relationships between nutrient uptake, plant performance, and product quality of grapevines and container-grown rhododendron are poorly defined. We are continuing on-going studies that manipulate nutrient supply to determine how different nutrients alter canopy development, physiology and berry (primary and secondary) metabolites important for quality and how nutrient availability influences fertilizer use and end-product quality (cold tolerance) of container-grown nursery plants. This information will be used to optimize nutrient management strategies for maximum plant response with minimal environmental impact.

Interactions between plants and mycorrhizal fungi alter the physiology and nutrient uptake of small fruit and nursery crops, but plant benefits from mycorrhizas are a function of fungal diversity, plant growth habit, and soil conditions. In vineyard production systems, we are continuing on-going studies that identify major root-colonizing species of arbuscular mycorrhizal fungi (AMF), and test how location in the field, soil depth and cover crops alters the diversity of fungi that colonize roots of grapevines. With geophyte crops used in floral crop production systems, we are investigating how resource allocation patterns altered by AMF influence product quality and determine whether the effects of AMF on plant nutrition result in significant impacts on product quality. Additionally, we are assessing how AMF alter end-product qualities (polyphenolic profiles) of medicinal and culinary herbs and whether ericoid mycorrhizal fungi (EMF) can decrease nutrient run-off from container production systems. This information will be used to determine how benefits from mycorrhizal fungi can be enhanced to increase production efficiency and product quality in grape and nursery crops.

Research results from our previous project will be used as a basis for evaluating different management practices and integrating these practices with those currently used in production systems. Information related to our previous research 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 related to our previous research 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.


4.Accomplishments
1. Basil is influenced by inoculation with mycorrhizal fungi. Nutrient management practices can influence plant production of phenolic compounds and it is unknown whether mycorrhizal fungi have similar effects on these quality components. ARS researchers in Corvallis, Oregon, determined that inoculating basil with arbuscular mycorrhizal fungi (AMF) increased concentrations of specific polyphenolics. Basil contains chicoric acid (an antioxidant), the supposed active ingredient in Echinacea. Antioxidants are known for their potential human health benefits. This research increases knowledge of sources for antioxidant compounds, and provides consumers with a potentially more accessible and less expensive source of chicoric acid than Echninacea.

2. Nitrogen alters cold hardiness of nursery trees. Stem and bud dieback due to winter injury causes economically important losses in nursery tree production and it is unknown whether plant N status, per se, or the type of fertilizer used influences cold hardiness. Using deciduous bareroot nursery trees, ARS researchers in Corvallis, Oregon, and university collaborators determined that both nitrogen rate and nitrogen form influenced cold tolerance of buds and stems of nursery trees. Trees with a similar nitrogen status withstand different levels of cold depending on the rate or form of fertilizer used during production. When developing nutrient management strategies for nursery production of trees in climates prone to winter injury, fertilizer component selection is an extremely important factor that should be considered.

3. Cover crop residue conserves soil moisture and enhances weed control and vine root growth. Cover crops have been shown to improve soil structure and weed control and it is unknown which cover crop practices are best suited for young vineyards in the PNW. An ARS scientist and collaborators at Oregon State University examined five different vineyard floor management schemes. One included the transfer of winter cover crop residue grown in alleyways as a mulch within vine rows in a young vineyard. The use of the mulch in the vine row increased vine shoot and root growth, suppressed numerous weeds, reduced soil compaction and maintained higher soils moisture over two growing seasons as compared to a clean-cultivated control without mulch. The findings suggest that the use of cover crop residues as a mulch can improve vine establishment and conserve soil resources and soil quality when establishing new vineyards in the Pacific Northwest region.


Review Publications
Tarara, J.M., Perez-Pena, J.E., Schreiner, R.P., Keller, M., Smithyman, R.P. 2011. Net carbon exchange in grapevine canopies responds rapidly to timing and extent of regulated deficit irrigation. Functional Plant Biology. 38:386-400.

Last Modified: 7/23/2014
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