Performing Department
Horticultural Science
Non Technical Summary
Non-technical Summary:Objectives 1, 2, and 3: The goal is to better understand how water-use efficiency changes when plants encounter interacting environmental stresses, particularly heat and drought stress. It is entirely unknown how these environmental factors, individually or together, impact the stomata VPD responses which govern the water use system. Since stomata VPD responses control transpiration and water use, the results will allow recommendations for modification of irrigation requirements in both turfgrass and mixed landscapes (urban environments with both turfgrass and woody plants).Objectives 4 and 5: This study will provide information about the potential benefits of creating pollinator-friendly habitat to promote insect pollinator diversity and conservation. Specifically, we will continue to explore the benefits of planting pollinator habitat in areas that are considered "marginal" and have not previously provided suitable pollinator habitat. We will also explore which wildflower mixes support the largest populations of pollinators in terms of both abundance and richness. Recommendations for seed mixes will be shared with NCDOT, and with the NC community through the Pollinator page on the NC IPM Portal (https://ipm.ces.ncsu.edu/ipm-honey-bees/).
Animal Health Component
0%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
Goals / Objectives:Summary: As we enter the new time of sustainability, education must extend into a broad range of areas. Systems interact with each other and the environment around them. So, any attempt to understand sustainability must involve background knowledge of several, often complex disciplines. Americans want safe, high quality greenspace in their urban environment. Nearly everyone would agree that these green spaces provide beauty to our landscape, reduce erosion, release oxygen, and filter pollutants from water. These areas also provide a necessary place for children to play - a more and more important factor in helping to reduce childhood obesity, one of the National Institute of Food and Agriculture's highest priorities. As of 2000, 79% of the United States population lived in urban areas, and as of 2010 that number grew to 80.7%. With climate change, a rapidly increasing urbanized population, and increase expanses of impervious surfaces, greenspace for recreation and as suitable wildlife habitat has decreased.Objectives 1 and 2: Traditionally turfgrass sites i.e. beautiful lawns, manicured golfcourses, etc. have been criticized for being a point of environment pollution. The current economic times, concern over environmental pollution, and climate change are collectively making everyone reassess past practices. There is a national move to develop more sustainable, and environmentally-friendly greenspace and turfgrass systems. The framework for the turfgrass portion of this project is based in ecological studies of managed turfgrass systems and the physiological responses of different turfgrasses to heat and drought. The end goal would be to make better recommendations to turfgrass managers, sod producers, and homeowners about what grasses are most suitable for their sustainable greenspace (be it a park, lawn, sports field, or golfcourse). Specific objectives under this portion of the project are:Objective 1: Determine the effect of heat stress on bentgrass growth and stress susceptibility under controlled environmental conditions.Objective 2: Evaluate water use by bentgrass and ultra-dwarf bermudagrass.Objective 3: This project addresses a major concern in the green industry and amongst urban ecosystem managers by focusing on landscape health and longevity, water management, runoff and irrigation issues (both priority areas as stated in the RFP).Increasing plant resistance to drought stress is one of the most important economic approaches to improve crop productivity, sustainability, and water conservation. Proper plant selection is one method for combating water scarcity in the landscape. Lists recommending plants suitable for use in these specific plantings are common and easily found, but lack significant scientifically-based support. We would like to support the industry and our community stakeholders by providing research-based woody plant selections that will be best suited to urban landscapes that are likely to experience greater drought events and higher temperatures in the future.The primary goal of this project is to use research pioneered by crop breeders and physiologists in crop plants to examine the drought tolerance of shrub species commonly planted in the Southeastern United States. More specifically, we will focus on plants generally recommended for use in bioretention areas and rain gardens in the Southeast. While these plants must be able to withstand standing water for short periods of time, they must ultimately be able to withstand prolonged periods of drought. Very little research has been performed on the drought tolerance of woody ornamental shrubs, especially those recommended for use in rain gardens and constructed bioretention cells, so this research is important to both stakeholders interested in planting in urban landscapes, but also to the scientific community at large.Objective 3: Determine the drought stress tolerance (water use efficiency) of different ornamental shrubs commonly planted in landscapes in the Southeastern United States.Objectives 4 and 5: Insect pollinators perform very valuable ecosystem services from which humans benefit. These ecosystem services include pollination of wildflowers which increases aesthetic appeal of the landscape, increases habitat for other wildlife, as well as providing critical pollination services for over 75% of the world's food crops. Fruits and vegetables from these crops provide essential macronutrients, vitamins, and minerals for a healthy diet. Of all insects, bees are considered to be the most beneficial pollinator for meeting these human needs, and comprise the largest order of insect pollinators, although flies, butterflies, moths, and wasps are also important insect pollinators.Disturbingly, over the past few decades bee populations have been in severe decline. Many factors contribute to this decline of bees, and indeed other insect pollinators, across the world. One of the major driving forces are the changes in our urban and suburban landscapes that include habitat loss, fragmentation, or alteration. Habitat loss due primarily from urbanization and alteration is a leading cause of pollinator decline by reducing foraging and nesting sites and have been linked to declines in the ~4,000 native bee-pollinator species in North America, placing a premium on habitat restoration for these critical taxa.Pollinators are attracted to wildflowers that produce sufficient amounts of pollen and nectar, so reduction in natural habitat can be devastating. Several habitat studies suggest floral abundance and quality of nesting sites have significant effects on pollinator abundance and diversity, leading us to posit that if we increase the amount and quality of pollinator habitat, then we can positively impact pollinator species richness and abundance. Long term impacts may also include an increase in the number and health of these pollinator populations.At the local scale, insect species richness is positively correlated with habitat quality. Habitat quality is usually measured as plant species richness or the abundance of plants needed for food and reproduction. Our previous work supports the idea that adding pollinator habitat to marginal lands does increase pollinator abundance and richness; however, with only one year's worth of research to draw from, more work is needed before publishing these results. The majority of these studies have been carried out in European agricultural landscapes with little to no work having been done in NC.Objective 4: Effects of pollinator plantings on species abundance and richness of pollinator populations.Objective 5: Research the relationships between landscape context and pollinators influenced by flower abundance in research sites (i.e. does surrounding land use impact the types of pollinators collected?)
Project Methods
Methods:Objectives 1 and 2: Several types of experiments will be conducted with creeping bentgrass, a cool season grass that is susceptible to water and heat stresses in the North Carolina climate and with warm season ultra-dwarf bermudagrass, a warm-season grass that is suited to heat and drought stresses in NC. The experiments will assess regulation of stomata and water use under increased heat and drought, as well as assessments of turfgrass quality and growth. A number of weighing scales have been purchased and integrated into a computerized system, which allows direct, continual measurement of water loss, i.e. stomata opening and closure. Experiments are typically conducted in a growth chamber, which allows imposition of high atmospheric temperatures. Low nutrition, restricted rooting volume, and excess water (low oxygen) in the root zone can be established. The conditions allow evaluation of plant controls when atmospheric demand for evaporation.A combination of the computerized measurement of water loss and VPD control allows for evaluation of light and dark water responses in a controlled environment (Phytotron). This is important because water loss in darkness is thought to be due primarily to evaporation from the soil. It is assumed that stomata are closed in darkness, limiting plant transpiration (See water loss at day and night below). We will be evaluating water use under light and dark responses in detail in virtually all experiments planned.Objective 3: This research will be conducted in a greenhouse at the Horticultural Field Laboratory, in Raleigh, NC. We will purchase plants, and replant them all into the same potting media, and uniform size pots. They will be allowed to acclimate for 3 weeks in the greenhouse. During the acclimation period, all plants will be watered regularly. At the start of the study, all plants will be watered to field-capacity, allowed to drain for 24 hours, then we will begin the dry-down study. All pots will be weighed daily, water use will be tracked, and the well-watered treatments (control) will be re-watered daily. The dry-down treatments will not be watered again. (We will have a minimum of 8 replications of each species.) Data collection will include plant quality, biomass parameters including leaf number, extension, and plant height and spread, and water-loss. At the termination of the study, all plants will be broken down for root mass, leaf area, and above ground dry-weights. We will replicate each series of species 2 to 3 times to determine water-use rates and develop dry-down curves for each species.Once we have estimated water-use groupings for the roughly 20 species (we anticipate being able to group plants into high-water users, medium-water users, low-water users or alternately, high-, medium, and low- water-stress tolerant) we will take the plants into the field to test in actual field settings. We will select about half of the species to use in field studies. Selected species will be established in replicated blocks, with low-, medium-, and high- water regimes. Quality data, biomass data, and fresh and dry weights - at the end of the study- will be collected. This will help to ground-truth our original estimations of water-use from the greenhouse study. Based on how the plants perform in the field we will be able to make better recommendations to growers, installers, and nurseries (as well as homeowners) as to which plants do best in rain-gardens, xeriscaped areas, and bioretention areas. We will use appropriate statistical analysis using SAS to determine statistical significance.Objectives 4 and 5: We will continue to work with the NC Department of Transportation (NCDOT); they have established 1000's of acres of wildflowers and pollinator habitat across NC. 30 of these areas (primarily in the Piedmont of NC) will be monitored for the duration of the project. Variables will include vegetation type (lightly-managed turfgrass vs. wildflowers plots) and land-use around the plots, established using ARC-GIS. Plant populations will be surveyed during the growing season 3-4 times. Pollinator populations will be surveyed biweekly during peak growing season - from May through September. The grassed plots will be mowed periodically per typical roadside maintenance and the wildflower plots will be mowed after the plants are dormant. We will quantify percent flowering at all locations, as well as pollinator abundance, diversity, evenness, and richness at each site using appropriate statistical analysis, and the Shannon-Weiner Index.