An integrated approach to developing nutrient management schemes for container-grown nursery crops

Final Report for LNE07-265

Project Type: Research and Education
Funds awarded in 2007: $106,562.00
Projected End Date: 12/31/2010
Region: Northeast
State: New Jersey
Project Leader:
Dr. John Dighton
Rutgers Universuty
Co-Leaders:
Gladis Zinati
Rutgers, The State University
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Project Information

Summary:

Over the three-year project we used an integrated approach of using fertilizers and natural soil mycorrhizal (NSM) fungi to develop nutrient management schemes for production of container-grown nursery crops. In 2007, we conducted a research study using three different fertilizers (Osmocote, Nutricote, and Polyon) and NSM fungi to grow oak, azalea, and thuja plants in containers. Results showed promising advantage of using NSM in increasing oak biomass and stem caliper, increasing tissue nutrient contents in oak and azalea plants. There was more mycorrhizal colonization in inoculated oak plants than in non-inoculated plants when fertilized with either Nutricote or Polyon. There was a near significant increase in percent fungal hyphae in azalea roots vs. non-inoculated. Root colonization in azalea was influenced by the type of fertilizer applied. It appears that the selection of Nutricote and Osmocote fertilizers, at the rates used in this study, would increase hyphal colonization of azalea’s roots when inoculated with NSM and provide a sustainable growth once outplanted in landscapes. Not only that, but it seems that by using Nutricote in presence of the NSM the overall mean concentrations of nitrous-N (NOx-N) and ortho-phosphorus (PO4-P) in leahcates from azalea were significantly decreased and similarly PO4-P, potassium (K), calcium (Ca), magnesium (Mg), sodium (Na) and electrical conductivity (EC) levels were significantly declined with Osmocote. Unlike azalea, the arbuscules count in inoculated thuja plants was constantly higher through all tested fertilizer types than non-inoculated ones. Inoculation of thuja plants with NSM did not change shoot, root biomass and tissue nutrient content. However, the inoculation reduced the overall mean NOx-N and ammonium (NH4-N) concentration in leachates compared to non-inocualted plants. This could be attributed to the increase in percent of hyphal and arbuscules of inoculated plants and aided in reduction of these nutrients in leachates.

The results were shared with growers and nursery clienteles during meetings, plant evaluation, and demonstrations. Out of the 135 people who attended the nursery meetings and field demonstration in 2007, 40 people attended the hands-on workshop in the second year (2008) of this project. The workshop included presentations, Q/A session, identification of mycorrhizae under microscopes, and field demonstration on sampling and inoculation techniques. In 2008, the team selected six nursery growers to represent a cross-section of New Jersey’s nursery growers (photos). In 2008, we made nine local and national presentations and published two abstracts in addition to publicizing the information on this project through flyers, handouts, NJNAES websites, NJNLA newsletters, and Rutgers PPA newsletters. We have reached 550 people during the second year project through these presentations. Many growers became very interested in using the natural mycorrhizae and consider it part of the crop production system especially after they have learned, experienced, and observed the beneficial effects of using mycorrhizae. We were very successful in raising the interest and awareness of both nursery and Christmas tree growers in using natural systems to increase crop productivity and engaging the nursery growers in developing their protocols of using NSM inoculums for growing their plants and share their experience at annual meetings. We continued to have invitations to present our results in 2009 throughout 2011 at local, national, and international conferences.
Results of our research were presented during workshops, regional and industry meetings, and provided nursery and Christmas tree growers with critical information on how: (1) to inoculate their plants with natural soil mycorrhizal fungi (NSM), (2) to use of fertilizers that promote colonization of natural mycorrhizal fungi in various plant species, (3) the incorporation of natural mycorrhizal fungi could reduce nutrient concentration of either nitrous nitrogen or ortho-phosphorus in nursery water runoff from containers based on fertilizer selection, and (4) to establish natural mycorrhizal fungi inoculum onsite.

These six implemented and integrated nutrient management schemes in container nursery production practices and continued to use these methods to increase sustainability of nursery production, profitability and protection of the environment. These six nursery growers were the nucleus to demonstrate the practical application of natural soil mycorrhizal fungi, to grow nursery crops, and exemplary stewards for their community.

Introduction:

Nursery, greenhouse, and sod production ranked number one among agricultural commodities in the last seven years in New Jersey. Nursery growers are under scrutiny due to excess use of fertilizers and excess nutrient losses to the environment. Heightened environmental and economic concerns make it necessary to develop production systems for the nursery industry that enhance plant growth and development of mycorrhizas, and other beneficial biological organisms, and decrease the nutrient concentration in effluent water from nursery production areas. The purpose of this project was to develop novel sustainable programs to bring awareness to the ornamental community about the advantages of sustainably managing nutrient and water practices for production of container-grown ornamental nursery crops. We seek to integrate the use of three types of naturally occurring mycorrhizal fungi into more environmentally benign and sustainable management programs for nursery crops. Our project to integrate mycorrhizal fungi will help in understanding whether selection of fertilizer has any effect on root colonization with mycorrhizal fungi and plant production, and whether fertilizer or mycorrhizal fungi reduce nutrient concentration in leachates, and increase tissue nutrient content and plant biomass of nursery crops. Consequently, the results will help to bring awareness to growers and industry clienteles to these advantages and train growers on the uses of mycorrhizal fungi, without sacrificing yields and profits.

Mycorrhizal fungi form beneficial association with roots of most cultivated and naturally occurring species of plants. Among the several types of mycorrhizae, ectomycorrhizae (EM), arbuscular mycorrhizae (AM) and ericoid mycorrhizae (ERM) are important for urban landscape plants. While ectomycorrhizal colonization tends to increase plant size (Garbaye and Churin 1996; Reid et al., 1983), arbuscular mycorrhizae are known for their ability to enhance phosphorus (P), Zn, and Cu uptake (Faber et al., 1990; Smith and Gianinazzi-Pearson, 1988) and ericoid mycorrhizae, associated with ericaceous plants (such as Vaccinium, Rhododendron), facilitate the transfer of nutrients to the host plant (Read and Kerley 1999).

The thrust of work in the past three decades has been towards evaluating the use of AM mycorrhizal fungi on horticultural crops on growth and root colonization (Black and Tinker, 1977; Davies et al., 2005; Klingeman et al., 2002; Koide et al., 1999; Sylvia, 1986; Wiseman et al., 2009). However, there was no research on uses of naturally-occurring mycorrhizae: ectomycorrhizae, arbuscular mycorrhizae, and ericoid mycorrhizae in conjunction of fertilizers to reduce nutrient concentration in leachates and improve plant yields of ornamental crops.

Our preliminary research study results (Zinati et al., 2011, pdf attached) showed that, natural ericoid root soil (NERS) inoculation increased shoot growth of Coast Leucothoe and Japanese Pieris by 56% and 60%, respectively. Shoots of Leucothoe inoculated with NERS had higher N, P, Mg, and Mn concentrations than non-inoculated plants. At low fertilizer rate, nitrous-N (NOx-N) and ortho-phosphorus (PO4-P) concentrations in the leachate were reduced by 53% from Leucothoe and 62% from Pieris compared to high fertilizer rate-treated plants. Based on these results we aimed on testing this concept using different types of fertilizers over a number of plants that require different mycorrhizal inoculum.

Based on the above results we examined the integrated approach over several types of plants, fertilizers, and sources of naturally-occurring mycorrhizal fungi. We have developed a research study in May 2007 to assess the use of naturally-occurring mycorrhizal fungi in increasing nutrient uptake, improving plant biomass, and reducing nutrient losses under three types of controlled-release fertilizers (Polyon, Osmocote, and Nutricote) when applied to three types of nursery plants.

The second part of the project was to provide hands-on training to 50 nursery growers and select seven growers to develop their nursery production protocols that included the use of natural mycorrhizal fungi on nursery sites. At each nursery operation, growers selected nursery crop species and assisted in setting up the experiment for data collection and assessing the impact of using naturally-occurring mycorrhizal fungi on nursery crops and compared to non-inoculated ones. Each grower was additionally surveyed for their opinions on the barriers to mycorrhizal adoption in nursery production, interest in adopting these practices, their thoughts and suggestions for future on-farm research.

Performance Target:

The primary objectives of this project were to: 1) develop integrated approach of using naturally occurring mycorrhizal fungi and fertilizers over a wide range of nursery crops, 2) train nursery growers and agricultural agents during a one-day short course (hands-on) workshop on developing nursery production protocols by using natural mycorrhizal fungi when growing nursery crops on nursery premises, 3) assess the system together with nursery growers, and 4) update the nursery clientele on the progress and results of this project, and address questions related to uses of natural mycorrhizea and uses of fertilizers.

Specific objectives:

1. Evaluate three nursery crop treatments that include 1) red oak 2) azalea, and 3) thuja when inoculated with naturally-occurring mycorrhizal fungi inoculum (ectomycorrhizae for red oak; ericoid for azalea; and arbuscular for thuja) when fertilized with three types of fertilizers ( Osmocote, Nutricote, and Polyon) for their impact on nursery biomass and growth, tissue nutrient content, nutrient concentration in leachates, and root colonization by mycorrhizal fungi when compared to non-inoculated plants.

2. Develop on-farm trials with six nursery growers in New Jersey for evaluation of selected mycorrhizal fungi on plant production. Producers will also be interviewed for their perceived challenges and benefits of using this system.

3. Promote technology and education transfer fertilizer and fungi management in nursery production systems among farmers, extension agents, NRCS agents, the NJ Nursery and Landscape Association, researchers and students.

Milestones and performance target:

Milestone 1: At least 135 nursery growers were educated on the benefits of the integrated nutrient management approach during the nursery field day, two state-wide annual nursery growers meetings, demonstrations, handouts, and newsletters.

Milestone 2: Out of 135, 40 nursery growers attended the one-day short course to further their understanding on the uses of fertilizers and mycorrhizae and have hands on experience on techniques used for inoculation and monitoring of leachates (photos of demonstrations).

Milestone 3: Out of 40 nursery growers, six were selected to test and verify the best treatments found in year’s one study (Image 12). The growers inoculated the selected plant species and amended it with commonly used fertilizer. They also monitored plant growth.

Milestone 4 and performance target: Six nursery growers implemented and integrated nutrient management schemes in container nursery production practices and continued to use these methods to increase sustainability of nursery production, profitability and protection of the environment. These six nursery growers were the nucleus to demonstrate the practical application of mycorrhizae and exemplary stewards for their community.

Research

Materials and methods:

An experiment was conducted under a simulated commercial nursery container production system at the Rutgers University Fruit and Ornamental Research and Extension Center, Cream Ridge, New Jersey from 17 May, 2007 through 12 October 2007. Three plant species were used as host plants: Azalea, and Oak, and Thuja. Non-rooted oak seedlings and uniform rooted liners of azalea and thuja were transplanted into classic 1200 black containers #3 to provide one plant per treatment per container, using growing substrate mix composed of 8 pine bark: 1 sphagnum peatmoss: 1 sand (by volume) with 5% clay on 17 May, 2007.

The experiment was a completely randomized design with four replicates for each plant species with a 3 X 2 factorial, including three fertilizers with and without (natural soil mycorrhizal (NSM) inoculum. The fertilizers, used in this study, were controlled-released fertilizers (CRFs): Osmocote® Pro (17-5-11); Nutricote® Total Blend Type 180 (17-7-8) and Polyon® Plus (17-6-12) which was suggested by New Jersey’s nursery growers to be tested as by the protocol of the SARE grant funding. Each plant was top-dressed at 56 g of each of the tested fertilizers 40 days after initiation of the experiment and inoculation of plants (as described below) and irrigated using a cyclic overhead irrigation system.

Natural soil and mycorrhizal inoculation of plants. The NSM inoculum that was used to inoculate oak and azalea was collected freshly from understory blueberry and huckleberry in the Pinelands forest close to the Rutgers Pinelands Research Station, New Lisbon, NJ. The natural soil and mycorrhizal inoculum used for the thuja plants was collected from a site on the research station where thuja plants were grown for four years. All plants were inoculated with NSM at the time of transplanting and placed under the root ball.

Plant growth measurements. On October 12, 2007, plant shoots (stems and leaves) were harvested, dried, and weighed. Roots were carefully cleaned for staining and counting root colonization.

Shoot nutrient content. A homogenous subsample of above-ground material was ground and assessed for nutrient content at the LSU AgCenter Soil Testing and Plant Analysis Laboratory (STPAL), Baton Rouge, LA, U.S.A.

Leachate collection and analysis. Leachates were collected from four replicates on 28 June, 7 July, 13 July, 27 July, 3 Aug., 10 Aug., 24 Aug., 7 September, and 21 September. Leachates were analyzed at the LSU AgCenter STPAL. Leachates were analyzed for ammonium, nitrate nitrogen (NO3-N), nitrite nitrogen (NO2-N), orho-phosphate (PO4-P), total phosphorus (TP), K, Ca, Mg, Cu, Mn, Fe, Zn, Ni, Na, Cl, EC, and pH. We report leachate (NO3 + NO2)-N as NOx-N.

Staining and assessment of mycorrhizal root diversity (oak) and colonization. Fresh roots were randomly selected from each plant and gently teased apart in water and substrate media particles carefully removed. Roots were cleared and stained and presence or absence of mycorrhizal structures (hyphae, arbuscules, coils, or spores) at 50 random locations on root segments was scored categorized into hyphae internal to the root cortex or hyphal coils. Root colonization was expressed as the percent of observations containing mycorrhizal structures (hyphae or coils) and was reported here as root colonization. Ectomycorrhizal colonization of oak roots was determined on an aggregate of random root samples taken from each pot. Ten randomly selected 1 x 1 cm Petri plate squares were observed for each sample. The total number of root tips in that area was counted and assigned to mycorrhizal categories, including non-mycorrhizal root tips, based on morphological characteristics. Mycorrhizal species richness (number of mycorrhizal types per sample) and Shannon Diversity Index of the mycorrhizal community were computed using PCOrd.

On farm-trials:

In 2008, six nursery operators were selected for establishing the protocol of integrated nutrient management using NSM fungi. Each grower selected one plant species to test and planted in a medium mix of 8:1:1 (bark:peatmoss:sand) in #2 containers (Image 1). On the day of planting, fresh root and soil inoculum, which included either ectomycorrhizae, arbuscular, or ericoid, were provided to nursery growers to inoculate their #1 container-grown nursery liner. The nursery growers were assisted in inoculating their plants (placing the inoculum just below the root ball) and topped with Nutricote fertilizer at 56 grams.

The plants included: Echinacea, Chamaecyparis, Azalea, Oakleaf Hydrangea, Oak, and Bigleaf Hydrangea. Except for azalea and oak, plants were inoculated with AM natural mycorrhizae. Azalea were inoculated with ericoid inoculum while oak plants were inoculated with ectomycorrhizae taken from roots of oak in natural forest.

Plants were arranged in complete randomized design with four replications and compared with non-inoculated plants of same species and placed on nursery sites. Standard irrigation practices used were followed at each nursery. These plants were not sprayed with any antifungal pesticides (to protect the mycorrhizal fungi inoculum).
These plants were evaluated for plant biomass (top and root), nutrient content in plant tissue and leachates collected from these plants.

Research results and discussion:

Experimental Research Station:

Our results showed that inoculation of oak plants with natural soil mycorrhizal (NSM) inoculum significantly increased top dry biomass (P =0.0006) and stem caliper (P =0.0136) irrespective of fertilizer type. The inoculation significantly increased tissue N, P, K, Mg, Ca, Cu, Fe, B, and Zn content of oak plants when compared to non-inouclated ones. Concentration of nitrate, phosphate, K, Mg, Ca, Mn, Na as well as EC in leachates collected from oak plants treated with Osmocote fertilizer were higher than those treated with other two fertilizers at the beginning of the growing season. However, concentrations of nitrate, phosphate, K, Fe, and Mn were greater in leachates collected from oak plants treated with Polyon fertilizer later in the season. There was more mycorrhizal colonization in inoculated oak plants than in non-inoculated plants when fertilized with either Nutricote or Polyon (Image 2). Azalea top biomass was only affected by fertilizer treatment, where it was highest in Osmocote. Azalea’s tissue N content increased significantly in inoculated plants whereas tissue P, K, Mg, and B content were affected by fertilizer treatment rather than by mycorrhizal addition. While the overall nitrate concentration in leachates was lowest in azalea plants treated with Nutricote, phosphate concentration was highest. The addition of NMS reduced significantly the overall nitrate and phosphate concentration in leachates from azalea plants treated with nutricote when compared to leachates from non-inoculated plants. There was a near significant increase in percent fungal hyphae in azalea roots vs. non-inoculated (Image 3). Root colonization in azalea was influenced by the type of fertilizer applied. It appears that the selection of Nutricote and Osmocote fertilizers, at the rates used in this study, would increase hyphal colonization of azalea’s roots when inoculated with NSM and provide a sustainable growth once outplanted in landscapes. As for thuja plants, there was no significant effect of either fertilizer, mycorrhizal inoculation, or their interaction on plant biomass and tissue nutrient content, except for N where the latter was significantly lower in osmocote treated ones. In thuja plants there was reduction in nitrate and ammonium concentration in leachates in NSM inoculated plants than non-inoculated, irrespective of the fertilizer treatment, and such nutrients were significantly lower in nutricote-treated plants, irrespective of the inoculation. Unlike azalea, the arbuscules count in inoculated thuja plants was constantly higher through all tested fertilizer types than non-inoculated ones (Image 4).

At the end of the growing season, nursery growers, industry clienteles, Extension agents, and representatives from NJNLA were invited for evaluating the plant growth and provide input on the results and plan for the on-farm trials (Image 5).

Hands-on Training Workshop

Nursery growers, nursery clienteles, Extension agents, mycorrhizal producing companies, and representatives from NJNLA and NRCS attended the hands-on training workshop that was conducted at the Rutgers Extension Office, Cumberland, NJ, on June 25, 2008. We made presentations (Image 6) and demonstrations (Images 7 and 8) on mycorrhizal collection from natural sites and examining slides under the microscope that showed spores, hyphae, and arbuscules in colonized roots.

On farm trials:

Results showed a significant increase in echinacea ‘Harvest Moon’ top biomass over root biomass in plants that received natural mycorrhizal inoculum. Inoculated plants showed a significant increase in spent, open, and closed flowers (Image 9). The growers found the use of arbuscular natural mycorrhizae for Echinacea improved the biomass and the nutritional quality of the plants where the foliage was greener than those non-inoculated (control) plants. While the tissue N and P levels were significantly higher, K levels were lower in mycorrhizal plants than in the control. Tissue Cu, Fe, Mn, and Zn concentration were higher in Echinacea with mycorrhizal inoculation. The arbuscular index was almost twice in mycorrhizae plants and significantly different from that in non-inoculated plants.

The inoculated plants had higher top biomass than root biomass for the azalea ‘Karen Purple’, Bigleaf Hydrangea ‘Forever & Ever Double Pink’, and Oakleaf Hydrangea ‘Pee Wee’. However, the inoculated chamaecyparis plants had, although not significant, lower top and root biomass. No significant difference in oak plants.

Azalea plants with mycorrhizae were healthier, greener, and had higher shoot biomass than non-inoculated (Image 10). No significant difference in plant tissue nutrient concentration in all measured elements. However, it is important to note that micro-nutrients tissue concentrations were higher in above-ground and only Cu, Mn, and Fe in the roots for mycorrhizal-inoculated plants. Root mycorrhizal colonization index was significantly higher in inoculated plants than in the control.

The addition of arbuscular mycorrhizae was also effective for Oakleaf Hydrangea. It improved the foliage color and reduced the leaf spot in mycorrhizal plants (visually) and increased hydrangea plant shoot biomass when compared to control ones (Image 11). No significant difference in tissue nutrient concentration in mycorrhizal-treated plants when compared to control. Although the overall RMCI was not significant among treatments, spore index was significantly different and was 3-fold higher in mycorrhizal plants.

Similar results were found for Bigleaf Hydrangea, where shoot biomass was higher but not significantly. Tissue Cu and Fe concentration was significantly higher in mycorrhizae-treated tops and roots. The overall RMCI was not significant among treatments

Although there were no significant changes in shoot and root biomass for chamaecyparis, a significant increase in tissue P concentration was evident in mycorrhizal-treated plants. Similarly, there was an increase in chamaecyparis tissue Cu and Zn concentration by 27% and 16%, respectively, in mycorrhizal-treated plants. The overall RMCI and hyphal index were significantly higher for mycorrhizal chamaecyparis plants when compared to control.

Accomplishments/Milestones

Milestone 1: At least 135 nursery growers were educated on the benefits of the integrated nutrient management approach during the nursery field day, two state-wide annual nursery growers meetings, demonstrations, handouts, and newsletters.

Milestone 2: Out of 135, 40 nursery growers attended the one-day short course to further their understanding on the uses of fertilizers and mycorrhizae and have hands on experience on techniques used for inoculation and monitoring of leachates (photos of demonstrations).

Milestone 3: Out of 40 nursery growers, six were selected to test and verify the best treatments found in year’s one study (Image 12). The growers inoculated the selected plant species and amended it with commonly used fertilizer. They also monitored plant growth.

Milestone 4 and performance target: Six nursery growers implemented and integrated nutrient management schemes in container nursery production practices and continued to use these methods to increase sustainability of nursery production, profitability and protection of the environment. These six nursery growers were the nucleus to demonstrate the practical application of mycorrhizae and exemplary stewards for their community.

Participation Summary

Education

Educational approach:

Presentations:

Zinati, G.M. 2011. Managing Container Media Mixes to Optimize Water and Nutrient Management. Presented at the 2011 Long Island Horticulture Conference, Holiday Inn, Ronkonkoma, NY. Sponsored by Cornell Cooperative Extension, Suffolk County, January 28, 2011.

Zinati, G.M. 2010. Differences in nutritional, pest, and environmental damage to rhododendrons. Presented at the American Rhododendron Society, Park Ridge, NJ. Sponsored by the Tappan Zee Chapter, December 4, 2010.

Zinati, G.M. 2010. Managing the rooting environment to optimize water and nutrient management in ornamental production. Presented at the 2010 National Water Quality Conference, Symposium S1, Hilton Head, SC, February 22, 2010.

Zinati, G. M. and J. Dighton. 2009. Integration of natural mycorrhizae in production of container-grown nursery crops. Presented at the 2009 ASHS Annual Conference, St. Louis, MO July 28, 2009 (presentation was selected for podcast recording at ASHS conference).

Zinati, G. M., J. Dighton, and A. Gould. 2009. Substrate media, fertilizer rate, and mycorrhizal inoculum source affect azalea plant root mycorrhizal colonization and severity of Phytophthora cinnamomi infection. Presented at the 2009 ASHS Annual Conference, St. Louis, MO July 28, 2009 (presentation was selected for podcast recording at ASHS conference).

Zinati, G.M. Management of nursery plants using mycorrhizae. Presented at the South Jersey Landscape Conference and Nursery Growers Meeting, Masso’s Crystal Manor, Glassboro, NJ, December 3, 2008.

Zinati, G.M. and J. Dighton. Effects of fertilizers and naturally-occurring mycorrhizae on sustainable production of nursery crops. Presented at the Nursery Meeting at Cream Ridge, NJ, August 28, 2008.

Zinati, G., J. Dighton, R. Obal, J. Johnson, J. Frecon, and C. Nordstrom. Effects of fertilizers and naturally-occurring mycorrhizae on sustainable production of nursery crops. Presented at the 2008 ASHS Annual Conference, Orlando, FL, July 23, 2008.

Zinati, G.M. Future trends in nursery production. Presented at the nursery workshop “Future trends in nursery production: Using natural mycorrhizae a hands-on experience”, June 25, 2008.

Zinati, G.M. Updates on Research and Extension Activities: Related to the Development of Nutrient Management practices for Container-Grown Crops Using Naturally-Occurring Mycorrhizal Fungi. Presented at the South Jersey Nursery Growers Meeting, Millville, NJ, February 29, 2008.

Zinati, G.M. Mycorrhizae in the landscape. Presented at the Central Jersey Turf and Ornamental Institute. Angelonis Ceder Gardens, Hamilton, NJ, February 20, 2008.

Zinati, G.M. Nutrient management in container-grown nursery crops. Presented at the 2008 Long Island Horticulture Conference, Holiday Inn, Ronkonkoma, NY. Sponsored by Cornell Cooperative Extension, Suffolk County, January 30, 2008.

Zinati, G.M. The benefits and uses of mycorrhizae in Christmas trees: Ways to increase survival in plantings. Presented to Christmas tree growers at the New Jersey Christmas Tree Growers’ Association Winter Conference, Clinton, NJ, January 26, 2008.

Zinati, G.M. The contribution of mycorrhizal fungi in sustainable Landscaping. Presented at the 2008 NJNLA Trade Show – Educational Session, Somerset, NJ, January 17, 2008.

Abstracts:

Zinati, G. and J. Dighton. 2011. Natural soil inoculum benefits woody perennial growth and minimizes nutrient leaching in plant nurseries. Soil Ecology Society meeting in Plymouth, UK Sept 14 – 16, 2011.

Zinati, G.M. 2010. Managing the rooting environment to optimize water and nutrient management in ornamental production. Abstract Proceedings of the 2010 National Water Quality Conference, Hilton Head, SC.

Zinati, G. M. and J. Dighton. 2009. Integration of natural mycorrhizae in production of container-grown nursery crops. HortScience 44(4):1063-1064.

Zinati, G.M., J. Dighton, R. Obal, J. Johnson, J. Frecon, and C. Nordstrom. 2008. Effects of fertilizers and naturally-occurring mycorrhizae on sustainable production of nursery crops. HortScience 43 (4): 1126.

Zinati, G.M. and J. Dighton. 2008. Impact of fertilizers on ornamental nursery plant growth and mycorrhizal colonization. (abstract) Proceedings, ASA-CSSA-SSSA International Annual Meetings, Houston, TX.

Additional Project Outcomes

Project outcomes:

Impacts of Results/Outcomes

Nursery growers and landscapers are increasingly aware of the challenges of nutrient management and the approaches to reduce nutrient leaching through the integration of mycorrhizal fungi association and reduction of fertilizer uses to improve nutrient uptake and plant quality.

Nursery growers were involved in the planning, execution, and collaboration on this project. The first annual meeting and the field demonstration took place at the Fruit and Ornamental Research Center, Cream Ridge, NJ during the summer of 2007 and the other annual meeting took place at the RCE Cumberland county office, Cumberland, NJ during the fall of 2007. The two meetings and the field demonstration were very well received, with approximately 135 attendees. These educational sessions provided the background and the concepts of using mycorrhizae to reduce fertilizer use and the plant species that can be used with these mycorrhizae. The integrated approach seemed very appealing to the nursery growers and became more interested in learning about its application to reduce nutrient runoffs. Preliminary results were shared with the nursery growers and landscapers at these meetings. Handouts were distributed at these meetings as well. Before harvesting the nursery crops under study nursery growers were invited to evaluate nursery crops for plant height, width, canopy, greenness of leaves, shape of plants, and caliper.

In 2007, project objectives and sponsorship of the project were shared with around 1,000 people including nursery stakeholders, landscapers, contractors, and Rutgers students through newsletters, newspapers, radio programs, annual nursery growers meetings, bulletins, flyers, and announcements that were posted on Rutgers New Jersey Experimental Station calendar and New Jersey county websites. NJNLA sent twice broadcast faxes and reached 1200 people including NJNLA members, active, allied, and complimentary. The aims and the sponsorship of this granted project were announced at the two state-wide annual nursery meetings, south Jersey landscape conference, NJNLA annual dinner reaching 300 attendees. Announcements about the granted project, objectives, and meetings were listed in PPA-ornamentals newsletter, Gloucester Grower News, NJNLA newsletter, county meetings, Country Folks Growers, the Mid Atlantic Growers, Cultivating Cumberland -county newsletter, personal visits, mailing that reached over 500 people, articles transmitted to 10 newspapers, 2 radio stations, Rutgers NJAES website (internal and public calendars), and emails to 6-8 county offices with agents who have some nursery responsibilities.
In 2008, the impact of this project was tremendous. We have received many invitations to present our results on uses of mycorrhizae not only by nursery associations but also by associations involved with conifers and Christmas trees, master gardeners, landscapers, and mycorrhizae laboratories.
We have made nine local and national presentations and published two abstracts in addition to publicizing the information on this project through flyers, handouts, NJNAES websites, NJNLA newsletters, and Rutgers PPA newsletters.
We have reached 550 people during the second year project through these presentations. Many growers became very interested in using the natural mycorrhizae and consider it part of the crop production system especially after they have learned, experienced, and observed the beneficial effects of using mycorrhizae. In addition to nursery and Christmas tree clienteles, we engaged over 15 undergraduate students in this research project (Image 13).
We followed up and conducted an assessment for the project and its results during one-on-one visitations with the six nursery growers.We found that they became very interested in using the natural mycorrhizae and started to consider including natural soil mycorrhizal fungi as part of the crop production system especially after they have learned, experienced, and observed the beneficial effects of using natural soil mycorrhizal fungi. The Christmas and forestry growers were especially interested in adding the mycorrhizae to their seedlings especially at planting in field soils. The growers learned about the impact of using mycorrhizae for growing different plant species and how each plant could differ in its reaction to same source of mycorrhizae. While certain plant species could show visual and statistical increases in biomass, the data from tissue nutrition, root colonization, spore index, and hyphal index showed that additional benefits can be gained by using mycorrhiza and such benefits could also be extrapolated especially when plants are out-planted in landscapes. Spores and hyphal colonization are two important structures that aid in inoculating new soils and new roots. Except for Bigleaf Hydrangea, all tested plants showed root colonization and increase in either arbuscular, hyphal, or spore index. While mycorrhizal inoculated plants had higher levels of micronutrients than non-inoculated plants, it was interesting to find that the tested plant species varied in their Cu, Zn, Fe, and Mn tissue concentration.
We found that the one-on-one visitations to these nursery operations were very beneficial especially because the growers had further questions on uses of mycorrhizal fungi for specific plant species and how to establish their own source of natural mycorrhizae on their operations.
Data analysis is complete and we are currently writing manuscripts for publication.

Farmer Adoption

1. Most of the grower participants involved in this project are considering the incorporation of natural mycorrhizal fungi in their nursery crop production, especially for low-fertilizer requirement and flowering plants.
2. The majority of grower participants in the one-day workshop were interested in establishing land space on their nursery operations dedicated to production of naturally-occurring mycorrhizal fungi for primary nursery crop species produced at their operations in order to inoculate their plants. A few were already using them and exchanged ideas with other producers on ideas for choosing mycorrhizae and management.
3. The farm-trial was very educational and brought awareness of both researchers and growers on development and implementation of the integrated approach and provided evidences at least visually for example grower who planted Echinacea. The grower found that his profits can be increased significantly just by using natural mycorrhizal fungi to increase biomass and number of flowers. Others found that the use of mycorrhizal fungi provided greener color and healthier plants as in Bigleaf hydrangea and azalea.
4. Nursery growers learned that root colonization of nursery crops by natural soil mycorrhizal fungi vary with plant species and type of fertilizer. This was demonstrated when azalea was used as one of the crops. Azalea’s root colonization is influenced by the type of fertilizer was applied. It appears that the selection of Nutricote and Osmocote fertilizers, at the rates used in this study, would increase hyphal colonization of azalea’s roots when inoculated with NSM and provide a sustainable growth once outplanted in landscapes.

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

Nursery growers were intrigued by the uses of natural mycorrhizal fungi and wanted to compare these fungi with the commonly used commercial mycorrhizal fungi and assess the benefits when fertilizers used at low and high rates of Nutricote. These issues were addressed on continuing studies funded by SARE during 2009 under Partnership grants ONE08-092.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.