Grant Information
| Knowledge Area | Subject of Investigation | Field of Science | Percent |
|---|---|---|---|
| 205 - Plant Management Systems | 999 - Citrus, general/other | 1020 - Physiology | 90% |
| 205 - Plant Management Systems | 210 - Water resources | 1020 - Physiology | 10% |
· Enter Non-Technical SummaryPrevious research has shown that tree water needs for healthy growth can be sufficiently predicted based on specific, easily measured dimensions of tree size, and a now common measure to environmental demand. To date water requirements for six tree species native to the eastern half of the USA have been characterized. This project will complete the same characterization for three different tree species, and mostly characterize the water demand for the last three major tree species east of the Rockies. Due to vast differences in climate, these model cannot be not applied beyond the eastern edge of the Rocky Mountains. These characterizations permit calculation of tree water needs for these 12 species which will improve efficiency and conserve irrigation for these major important tree species.Prior to the year 2000, most budded citrus trees were produced in the ground in fields in outdoor nurseries. With the very wide spread of citrus canker caused by three hurricanes in 2004, production of young budded citrus trees was forced inside of greenhouses with fine mesh screens and into plastic pots. To be economical, pots were small and trees were crowded heavily to reduce per tree cost. This induced numerous issues related to budded tree quality and quantity previously unimagined, leaving less than 20 major producers of budded trees with very limited knowledge of production practices in inclosed greenhouses. Since my adoption in 2012 to lead research to accelerate and solve production issues for this segment of the citrus industry, rapid advances have been made. However remaining issues are not as easy to solve, but their solutions will provide important and needed advances to keep citrus a viable crop throughout the USA.
1. Seedlings of Quercus shummardii (Shumard oak), Carya glabra (Pignut hickory) and Washingtonia robusta palm were transplanted into #3 and #7 containers using a 70% pine bark (
Target Audience
Target audience - Target audience consisted of mainly the 54 citrus nursery greenhouse operations in Florida, and a few in Georgia. Other probable audiences comprised of citrus nurseries along the southern part of the US, stretching westward up through California. Additionally, connections with the University of Virgin Islands made in 2018 may expand the benefits of the research to other areas.
Changes / Problems
The major problem is lack of funding. The citrus nusery industry in the USA is dwarfed by the thousands of acres of citrus groves. One potted citrus plant usually takes up 4x4 inch pot spacing during producton. But once in the grove, the same tree is given a minimum of 145 sq. ft at 300 trees per acre. Thus that one tree in a grove represents 1308 young trees. Hence, securing funding for the major issues confronted by these relatively tiny footprint, but critical links to grove production in near impossible at the national level.
Training & Professional Development
The Florida Nursery Greenhouse Landscape Assocation usually has a full day of presentations for Citrus Nursery Growers once or twice a year. During these sessions, nursery growers gain new insights and knowledge from recently completed research projects.However there is little actually training on a professional level.
Dissemination Streams
Most of the dissemination occurs at the annual or bi-annual meetings sponsored by FNGLA Citrus Division. At each meeting, growers are given a notebook that has all PowerPoint presentations. In addition growers and presenters have time to seek out each other for one-on-one or impromptu question and answers. In addition, I response to growers' questions by phone or email. When asked, I travel throughout the state of Florida to assess and hopefully respond meaningfully to citrus nursery growers and sometimes landscape questions.
Next Reporting Steps
I will continue to measure ETo and ETA of the Shumard oaks and Washingtonia palms at the site and measure trunk calipers and canopy spread generally every 3 weeks when trees are in leaf. Trees will be repotted into 200 gal pots and replaced in the weighing lysimeters in early March 2019. For citrus, I plan to apply growth regulators to budded trees to try to limit shoot elongation for quicker development of scion stem caliper. I also plan to test a concentration gradient of adding silica to the organic substrate used by most nurserymen. If funding can be secured, I plan to tackle a major issue in citrus nursery production - dry air.
Target Audience
Target audience was citrus greenhouse nursery growers who grow rootstocks that are budded with desired citrus cultivars. These are then growth to a minimum size and sold for outplanting in groves. The second audience is for water managers in tree nurseries and landscapes that strive to produce and maintain good tree quality without excessive irrigation.
Changes / Problems
Nothing Reported
Training & Professional Development
Nothing Reported
Dissemination Streams
Results have been spread through meetings of Florida citrus greenhouse growers in the Spring Nusery Update. Two manuscripts have been written on citrus rooting that are in review or in press. Similarly 2 manuscripts of the water use and modelling of shade trees have been published or accepted for publication.
Next Reporting Steps
Trees of palm and oak will continue to be measured every 3 weeks during the growing season for increases in tree size. These will be repotted into 90 gal containers in early March, with identical measurement recorded as in previous years. Peach trees will be transplanted into the weighing lysimeters were the hickory trees were remvoved. New experiments in citrus nursery greenhouse production will be initated based on growers request <br><br>
<br>What was accomplished under these goals? ETA was measured every half hr for the Shumard oak and palms. Measurements of tree heigh, trunk caliper in 3 locations and canopy spread were recorded every 3 weeks on the oaks. Similar measurments on the palms were also successful, with lysimeter trees increasing size 3-fold. Unfortunately, all hickories were exceptionally slow to leaf out, with almost no shoot growth thoughout the period. Most died. This species was removed from the experiment. Models for quantifying irrigation requirements will not be availble until the end of the project. For citrus produced in phyto-santary greenhouses, 2 levels of shade and an unshaded control established. Trees will be budded in the fall of 2017. Propagation of citrus rootstocks by cuttings was proven to be highly successful during the period from early march to early November in Central and South Florida. Best success occur during this period with cuttings with 3 to 4 leaves. However single leaf and bud cuttings also rooted near 100% during the optimum time of the year using 7500 ppm Dip-n-Gro diluted with a thickening agent. This was proven on over 20 cultivars and species of citrus rootstocks. <br><br><b>Publications</b><br>