Floriculture Environmental and Modeling Research 1992 Proposal
This proposal is a request for fourth year funding of a project approved
for the first time in 1988. The research is in two general areas. The first
area is under the direction of John Biernbaum and is to define the changes
in irrigation and fertilization practices that must be adopted if our industry
is to stop runoff of water and fertilizer from greenhouses and survive
decreasing water availability. The specific objectives are to investigate
1) irrigation and fertilization practices and scheduling, 2) root media
nutrient analysis methods and recommendations, 3) root media water and
nutrient efficiency. The second area is under the direction of Royal Heins
and involves research to increase our understanding of how temperature
and light can be used to regulate plant growth. The specific objectives
are 1) to investigate control of stem elongation by day and night temperature,
2) to develop plant growth models, 3) to develop grower management tools,
and 4) to investigate long term storage of seedlings and flowering plants.
The research will have both immediate and long term benefits for the
floral industry. Recommendations will be developed to help operators of
both large and small greenhouses manage both the crop root zone and the
greenhouse atmosphere. The goal is to maximize production efficiency and
product quality while minimizing environmental impacts. Information about
limiting water use and preventing ground water contamination will help
the floral industry as environmental regulations force changes in irrigation
and nutritional programs. Information detailing how temperature can be
used for precise control of plant growth will improve plant quality, allow
reliable production of plants to market specifications, and reduce the
use of growth regulating chemicals.
INTRODUCTTON AND BACKGROUND INFORMATION
This proposal describes proposed research associated with the fourth
year of a five year project approved for the first time in 1988. Our original
proposal detailed a research program that would address the objectives
outlined for a minimum of five years. We have assumed that copies of proposals
from the first three years with the background and literature review outlining
the problems of environmental pollution and regulation of plant growth
are available to the R&D Committee and Trustees. The level of concern
about environmental issues like water and fertilizer runoff, the application
of methods to control Plant height and development, and attendance at grower
seminars covering these topics has grown dramatically in the past three
years and is evidence of the importance of the research being done in this
project.
We have submitted under separate cover a notebook containing publications
from the MSU Floriculture Program for the 1990-91 academic year. The two
project leaders together with Dr. William Carlson and graduate students
had a total of 6 refereed scientific articles, 19 extension and trade press
articles, plus numerous grower presentations at national and local grower
meetings. Articles in this notebook summarize our published accomplishments
for the past year. This proposal outlines current projects and planned
projects for the coming year. Similar to the original proposal, we have
outlined a broad, programmatic approach to developing solutions for problems
facing the greenhouse industry rather than limited, specific projects.
Due to the format of our proposal and because this is a request for continued
support, there is no specific Materials and Methods section or Facilities
and Equipment section in the Proposal. Because funding for the first three
years was less than half of that requested to meet the objectives outlined,
some of the planned projects have not been completed and are repeated or
modified in this proposal.
OBJECTIVES AND PROPOSED RESEARCH
The broad research objectives supported by this project are:
1) to develop basic information on factors influencing the growth of
floriculture crops.
2) to develop information which will have immediate impact at the grower/manager
level of floriculture crop production.
3) to solve problems which are of immediate concern and already exist
in commercial floriculture production.
CURRENT AND PROJECTED RESEARCH INVESTIGATIONS - DR. BIERNBAUM
The primary goal is to provide greenhouse operators with methods to
limit fertilizer and water runoff, to conserve water, and to improve irrigation
and fertilization techniques. The following projects will continue to provide
the detailed information that growers will need as they begin to implement
changes in irrigation and fertilization practices. Efforts in 1992 will
be concentrated in three project areas. They are 1) irrigation and fertilization
practices and scheduling, 2) root media nutrient analysis methods and recommendations,
3) root media water and nutrient holding properties.
The topic of plant pathogens in recirculated solutions that has been
a major part of the last three proposals has not been included this year.
While pathogens in recirculated solutions were a major concern four years
ago, there is an ever growing body of evidence that plant pathogens in
recirculated water are not a major problem in most areas of the United
States. The fact that growers are accepting this point may be a major factor
in why more growers seem willing to implement changes now. That part of
our research is completed and will be replaced by an increased emphasis
on root media nutrient analysis.
1) Irrigation and Fertilization Practices and Scheduling. Critical evaluation
of our fertilization techniques is the best approach to limiting water
and fertilizer runoff from greenhouses. Our objective for this project
is to take a quantitative approach to determine how much water and fertilizer
is required to produce a specific crop and to define how that fertilizer
should be applied over the life of the crop. The emphasis over the last
year has been equally split between traditional topwatering systems and
pulsed subirrigation systems. Based on the past 2 years of work, we now
know that lower than recommended levels of fertilization and root media
nutrient levels (hereafter referred to as EC, for electrical conductivity)
can be used with both subirrigation and traditional methods. In research
to be completed in 1992, we must continue to test the contention that plants
can be grown with much less than currently recommended fertilizer levels.
The majority of our efforts have targeted two major greenhouse crops,
bedding plants and poinsettias. Ten experiments have been completed with
poinsettias over the last 3 years demonstrating the effects of leaching
and fertilizer concentration and establishing the amount of fertilizer
necessary to grow poinsettias. We are also working with chrysanthemum and
Easter lily. One experiment was completed with subirrigated chrysanthemum
this spring (1990) and like with poinsettias, the plants produced with
the lowest fertilizer concentration applied were as good as those produced
with the higher concentrations. This is important because chrysanthemums
are perhaps the most heavily fertilized crop in our industry. Our efforts
in 1992 will continue to be to define how much water and fertilizer are
needed to produce bedding plants, poinsettias, chrysanthemums and Easter
lilies with the greatest emphasis on chrysanthemums. In 1992 we plan to
test the values we have developed to date by growing these crops in a pure
rockwool media. Rockwool is a fibrous, inert media component with high
water holding capacity that is mixed with peat moss by commercial media
manufacturers. The loose rockwool that is now available can be used like
a normal peat based media used by growers but with more precise control
over exactly what is available to the plant. These experiments can be completed
using traditional growing containers and methods so the results will be
applicable to commercial conditions.
Another part of this project has been to generate information about
subirrigation systems with total water recirculation. With funds provided
by a special grant from the Michigan Agriculture Experiment Station, 18
small sections of flood bench were purchased and will be set up with individual
reservoirs and pumps. This new setup will allow us to do better trials
than possible in the past. More treatments can be tested with better accuracy.
Also as part of the special grant, irrigation controllers are being installed
for the flood irrigation systems in all our research greenhouse sections.
This equipment, which has been selected to demonstrate a range of low cost
and high cost commercially available control systems, will provide a wealth
of experience and information about recirculating solutions on a commercial
scale. By the end of 1991, 108 benches totaling 4,800 square feet of bench
area in our greenhouse facilities will be fully recirculated and automated.
This is being accomplished with a 1991 investment of over $50,000 by the
Michigan Agriculture Experiment Station and $15,000 from growers contributing
to the MSU research program. The information that will be generated during
1992 and beyond using this irrigation equipment in our research facility
will help greenhouse operators move into the next century.
As outlined in the Spring Research Report, over the past year we have
identified some important new information. Our studies of fertilizer distribution
throughout a pot has perhaps provided an important explanation for why
we fertilize the way we do and how to reduce fertilization. We have found
that in many cases, fertilizer migrates to a small layer at the top of
the pot where it is not readily available to the plant. This migration
is due to the evaporation of water from the surface of the pot. As much
as 20 to 50% of the water loss from container grown plants is by evaporation
from the surface as compared to transpiration by the plant. What happens
when this evaporation is stopped has been a major focus of our research
the past 12 months. In several experiments during 1990 the effect of a
pot cover on irrigation and fertilization requirements was tested. Fertilizer
stratification in the media was reduced and water/fertilizer applications
were reduced by 20 to 30%. Water loss was also reduced in post production
evaluations by as much as 40 to 50% in some cases. In one test under conditions
to simulate a post production consumer evaluation, the time to wilt for
poinsettias in 4.5 inch pots was extended from approximately 7 days for
plants without a pot cover to 13 days for plants with a pot cover. Specific
data will be submitted with the September Progress Report. Growing plants
with pot covers will continue to be investigated in 1992 as part of our
efforts to improve fertilization and irrigation methods.
2) Root Media Analysis and Recommendations. One of the most important
problems we have identified over the past two years is the general lack
of grower knowledge of how to determine if adequate levels of fertilizer
are being applied. Traditional fertilization methods have depended on heavy
leaching with higher than needed concentrations of fertilizer so media
testing was not as important. The lack of clear directions and recommendations
for media analysis is also to blame. We have produced crops in many of
our experiments with root media nutrient levels well below those currently
recommended. Experiments are planned for the fall of 1991 and a primary
goal for 1992 is to continue our efforts to generate the necessary information
and make it available to encourage more root media analysis. Root media
analysis methods and recommendations is one example of an area where more
specific information and details will be needed as best management practices
are implemented. As fertilizer applications are reduced, growers will depend
more and more on media analysis to determine fertilization practices. Increased
root media analysis is a key to limiting fertilizer runoff.
How to efficiently change the root media EC from one value to another
must also be investigated. We currently know how to change root media EC
two ways. The first is to leach with large volumes of solution at the desired
EC. This method achieves the goal quickly but large amounts of water and
fertilizer are wasted and runoff is produced. The second method is to add
a lower than desired concentration with minimal leaching to allow the root
media EC to gradually increase and attain the desired value. We think there
is a third approach. This method would involve knowing the current root
media EC value and the desired EC value and then estimating what concentration
needs to be applied with no leaching, such that when the solution in the
pot is mixed with the applied solution, the desired EC results. For example,
if the media EC is 1 and a value of 2 is desired, the addition of a solution
with an EC of 3 may result in an EC of 2. The fertilizer concentration
in the solution with an EC of 3 would be significantly higher than what
is currently recommended to apply without leaching. This idea must be tested
to determine the effect on plant growth and the relationship of media EC
and applied EC. This will be a major project for 1992 and 1993.
This project of relating fertilizer concentration with initial EC and
final desired EC will be under the direction of both Dr. Biernbaum and
Dr. Heins. Our goal is to take the information collected and develop a
graphical track or target root media EC for a specific crop and set of
conditions. Growers would determine the current EC level, know the desired
EC level, and information would be presented on how to get from the current
to the desired. This system could be refined to work for specific growing
conditions and would be the much needed tool to help growers refine and
improve irrigation and fertilization methods.
3) Root Media Water and Nutrient Efficiency. The objective of this project
is to identify methods of efficiently keeping water and fertilizer in the
growing container and available to the Plant. This can be done by careful
selection of root media components and amendments like wetting agents.
During the first two years of this project, three experiments were conducted
testing different root media and amendments. Application of a wetting agent
to peat based media was identified as a method to increase water retention.
Rockwool was identified as a new component that would increase water holding
capacity. Nutrient retention has not seemed to be a limiting factor but
will continue to be evaluated. In many of the fertilizer experiments outlined
under the two previous project areas, several media have been and will
continue to be included in each test to evaluate the effect of root media
on fertilization methods.
An experiment testing the effect of 16 different root media with two
fertilization methods on the garden performance of impatiens hanging baskets
was completed during 1990. Based on results from the basket experiment,
we can demonstrate the effects of the major components on water holding
capacity. Depending on the root media components, the time from watering
to wilt varied from one day to three days. We also learned that under many
conditions superabsorbant acrylimide gels like the one tested will not
significantly effects water availability. In follow up experiments currently
in progress, 240 hanging baskets are being maintained from June 1, 1991
until approximately October 1, 1991 as part of five experiments. Ten different
commercial root media were used to produce hanging baskets at MSU and baskets
were also collected from 10 different growers in Michigan. The amount of
available water is being evaluated and compared. This is a very practical
way to learn about the characteristics of the most common commercial root
media. Long term fertilization with resin coated fertilizer (RCF) is being
investigated in two experiments and the nutritional requirements of the
six major hanging basket species are being evaluated in a separate experiment.
This information will not only help growers but will also improve consumer
satisfaction with hanging baskets. From this research we have also learned
that the amount of water and fertilizer held by the media is only one part
of what needs to be considered. How the water and nutrients are released
to the plant is also very important. Components or amendments that make
water less available or slowly available to the plant can extend the time
period between irrigations and reduce water requirements. Our research
efforts in 1992 will be directed at methods to alter water availability.
Other Areas. Our review of the existing research literature and collecting
information useful to the greenhouse industry has continued. The filing
system and computerized data base that can be automatically searched a
number of different ways has been expanded from approximately 500 articles
on file to over 1000 articles covering the topics of fertilization, irrigation,
root media analysis, root media and pathogens in water from the past 50
years. This work will continue in 1992.
Grower education is a significant component of our research. During
the past year, Dr. Biernbaum has cooperated with the Horticulture Water
Quality Alliance formed by The Professional Plant Growers Association,
The Society of American Florists, Roses Incorporated, and the Association
of American Nurserymen. Much of the information generated from the research
outlined in this proposal and information collected for the data base mentioned
above was made available for the Water Quality Action Manual that is under
development. The role of the American Floral Endowment in making this information
available to greenhouse operators was recognized at every opportunity.
Several large greenhouse operators in Michigan are currently in the
process of developing and implementing water management strategies. Five
operations have been identified as examples for a case study approach to
an educational short course that would be presented in the future. Information
is being collected about how each operation approached the situation and
what solutions were implemented. The goal is to develop a set of recommendations
or a plan for what steps should be taken and what alternatives are available
when developing a water management plan.
CURRENT ACTIVITY AND PROJECTED RESEARCH INVESTIGATIONS - DR. HEINS
Investigations during the past three years have addressed the control
of stem elongation using temperature (DIF), the effects of temperature
on Easter lily flower initiation and plant development rate, the effects
of light and temperature on African Violet and Christmas cactus flower
initiation and development rates, and the effects of temperature and light
during plug storage on seedlings growth after storage. The underlying theme
of this research program is the development of quantitative relationships
between plant development and the environment, specifically temperature
and light. The research during the coming year will continue this theme
with the following emphasizes.
1) Investigations into the control of stem elongation by day and night
temperature. We have published information on how the relationship between
day and night temperature influences stem elongation. Briefly, stem elongation
in plants responds to the difference (DIF) between the day and night temperature.
As the day becomes progressively warmer than the night, stem elongation
increases. Conversely, as the day becomes progressively cooler than the
night, stem elongation decreases. This information has become a powerful
tool in the hands of growers attempting to control the height of most plant
species in the greenhouse. Height control becomes easier while growth regulator
costs decrease. Use of DIF has become widespread among growers for plant
height control.
One of the most common questions growers still have about DIF relates
to the interaction between a cool temperature pulse at sunrise and subsequent
higher temperatures later in the day. We know that high day temperatures
after noon partially negate the benefit realized from a dip in temperature
at sunrise. The growers wish to know how much of the height control benefit
realized from the morning dip is lost later in the day. Research during
the coming year will be designed to develop a quantitative relationship
between stem elongation and the interaction between negative and positive
temperature pulses during a day. This information will help growers make
informed temperature management decisions.
2) Development of growth models. During the past year, modeling efforts
have centered on developing time to flower models. A model relating Christmas
cactus flower bud size and temperature to time to flower was developed.
This model can be used by the grower to predict when his/her crop will
flower based on bud size and temperature or alternatively, the model can
be used to determine the proper temperature so a crop with buds of a certain
size will flower on a desired date. Models relating leaf unfolding of African
violet and Aster with temperature were also developed. Likewise, time to
flower models for African violet and Aster were developed.
Data to develop leaf unfolding models were collected on Christmas cactus
and Easter My. The Christmas cacti data will be used to develop a model
relating pad development rate to temperature. Likewise, a model relating
leaf unfolding of the lily to temperature and initial bulb size will be
developed. A model currently exits for the Easter lily but is limited to
plants developing from 8/9 bulbs. Leaf unfolding rates are different at
the same temperature for plants developing from different sized bulbs.
The new model will cover all bulb sizes.
3) Development of grower management tools. It is logical to ask the
value of the models we are developing. By themselves, the models are worth
little to the grower. Developed into management tools, however, they can
be extremely valuable. An example management tool we have developed in
the past is Graphical Tracking. In graphical tracking, current plant height
is compared with expected plant height over time. Informed decisions about
height control can then be made. Graphical tracking procedures have been
developed for poinsettias, chrysanthemum, and Easter Lilies based on our
modeling studies on stem elongation. Based on grower contacts, we estimate
25 to 50% of the U.S. Easter lily crop and 10 to 20% of the poinsettia
crop is now grown using graphical tracking.
The next generation of grower management tools, an Expert System, is
now being developed. The expert system is being developed to extend graphical
tracking to include expert advice from a computer program. The first expert
system will be for poinsettia height control and is currently being developed.
The poinsettia expert system program will combine graphical tracking with
specific height control advice. The advice will be based on current plant
height, current plant growth rate, previous growth rate, current stage
of crop development, cultivar, time since the last growth retardant application,
previous DIF conditions, and expected DIF conditions. The poinsettia expert
system program will be in 5 to 10 commercial greenhouses during the fall
of 1991 for testing.. It is being funded in part by Paul Ecke Poinsettias.
A similar expert system to assist chrysanthemum growers make height control
decisions is scheduled to be developed by Jan. 1, 1992. The chrysanthemum
program is being funded in part by Yoder Brothers, Inc.
If monies are approved for this AFE proposal, an Easter lily height
control expert system similar to the poinsettia and chrysanthemum expert
systems will be developed. This Easter lily expert system will combine
advice for both height control (DIF and growth retardants) and for crop
timing.
4) Long term storage of seedlings. One important new area of research
was started two years ago and will continue during the next year of funding.
As an outgrowth of the modeling research, we have studied plug seedling
storage for extended periods of time at low temperatures in the dark or
with very low light levels. Under optimal conditions, impatiens and petunia
plugs were stored for up to six weeks in a cooler with no detrimental effect
on later growth and flowering. Geranium plugs have been stored up to 4
weeks and pansy plugs up to 16 weeks with no detrimental effects on later
growth and flowering. With adequate funding, research in this area will
expand over the coming year. The potential to increase production and efficiency
of existing greenhouse facilities through the use of storage facilities
is dramatic. There is great grower interest in this research project.
SUMMARY
Two main projects each with specific project areas have been outlined.
The projects under the direction of John Biernbaum are to define the changes
in irrigation and fertilization practices that must be adopted if our industry
is to stop runoff of water and fertilizer from greenhouses and survive
decreasing water availability. The specific objectives are to investigate
1) irrigation and fertilization practices and scheduling, 2) root media
nutrient analysis methods and recommendations, 3) root media water and
nutrient efficiency. The projects under the direction of Royal Heins involve
research to increase our understanding of how temperature and light can
be used to regulate plant growth. The specific objective are 1) to investigate
control of stem elongation by day and night temperature, 2) to develop
plant growth models, 3) to develop grower management tools, and 4) to investigate
long term storage of seedlings and flowering plants. We will continue to
maintain a close linkage between our research program and commercial growers.
This allows ideas to be rapidly tested under commercial conditions.
BUDGET
Funding necessary to fulfill the objectives of our proposals during
the period of the proposal was set at $66,000 in 1989, $70,000 in 1990,
and $78,000 in 1991. Actual funding was $44,500 in 1989, $35,000 in 1990,
and $39,000 in 1991. We have maintained some activity in all objective
areas with the help of other funding but estimate progress is at least
a year behind what it might have been with full funding.
We have requested funding for four graduate students plus support for
this project during each of the past three years. Actual funding received
has only been sufficient to support two students, one student working for
Dr. Biernbaum and one for Dr. Heins. We accept that funding for more than
two students is unlikely during the coming year and therefore are limiting
our request to continued funding for the two students currently funded
by this grant.
1989 REQUESTED $66,000 FUNDED $44,500
1990 REQUESTED $70,000 FUNDED $35,000
1991 REQUESTED $78,000 FUNDED $39,500
1992 REQUEST 2 Graduate assistantships @ $15,000 $30,000
Research support @ $5,000/student/year $10,000
TOTAL REQUEST $40,000
1993 The request remains the same but increased by the rate of inflation
to maintain the program at the same level in real terms. This budget assumes
5% but actual requests in future years may vary as assistantship and inflation
costs vary. The estimated request for the fifth and final year of this
project is $42,000.
PROJECT LEADER QUALIFICATION NAME: JOHN A. BIERNBAUM DATE OF BIRTH:
April 3, 1957 ACADEMIC RANK: Associate Professor DEGREES: B.S. North Carolina
State University 1979 M.S. Pennsylvania State University 1981 Ph.D. Michigan
State University 1985 DATE JOINED MSU FACULTY: August 1, 1985 ACADEMIC
RESPONSIBILIITES: 80% Teaching, 20% Research ORGANIZATIONAL MEMBERSHIPS:
American Society for Horticultural Sciences International Society of Horticultural
Sciences Sigma Xi (Science honorary) Gamma Sigma Delta (Agricultural honorary)
Pi Alpha Xi (Floriculture honorary)
EXPERIENCE CAPSULE:
John Biernbaum has been on the staff of Michigan State University since
1985 when he was hired as an Assistant Professor to teach and conduct research
in floriculture nutrition. He was promoted to Associate Professor in 1990.
He was born in New Jersey, received his B.S. degree in 1979 from North
Carolina State University, M.S. degree in 1981 from Pennsylvania State
University and his Ph.D. in 1985 from the Michigan State University.
At Michigan State University, Dr. Biernbaum teaches a greenhouse management
course, foliage plant course, and part of a course on controlled plant
environment. He advises both 2 and 4 year undergraduate students, graduate
Masters and Ph.D. students. He has an active research program studying
the nutrition of flowering potted and bedding plants, media chemical and
physical properties and methods for reducing runoff from greenhouses. Two
students have received their Masters degree with Dr. Biernbaum as their
thesis advisor.
Dr. Biernbaum has authored or co-authored 25 extension and grower articles
and 6 scientific articles. He has spoken at over 50 grower meetings and
5 scientific meetings.
RESEARCH ACCOMPLISHMENTS OF STUDENTS IN PAST FIVE YEARS:
Developed recommendations for the reduction of fertilizer runoff for
commercial greenhouses. Locating the wells away from the greenhouse and
the reduced leaching of containers reduce the risk ground water contamination
of ground water. Alternative sources of water such as rain water could
be used in improving water quality in irrigation water. Currently several
major producers of poinsettia cuttings are using collected rainwater for
the mist propagation.
Determined that there is a low probability of transmission of Pythium
by subirrigation using recirculated solutions. The risk is much reduced
compared to top watering systems. With subirrigation, the normal pathways
of disease (wet foliage and splashing water) no longer occur. In the experiments,
only geraniums treated with silver thiosulfate and high concentrations
of inoculum were seen to have the Pythium move in the recirculated solution.
Determined that nutrient levels in a container are related to both fertilizer
concentrations and the amount of water leached from the container at time
of watering. Similar nutrient levels could be obtained by either a high
concentration of liquid fertilizer with a high volume leached or a lower
concentration of liquid fertilizer with a low volume leached.
Developed commercial recommendations for improving post-production quality
of hanging baskets. Showed that media that contains components such as
vermiculite or rockwool have a larger amount of available water and will
go longer between waters in a retailer/consumer environment. Determined
the amount of liquid fertilizer needed to sustain a quality impatiens basket
through both the production and post-production environment. Showed that
a similar amount of resin coated fertilizer with a 8-9 month release rate
incorporated prior to planting could not sustain a basket through the post-production
environment.
PROJECT LEADER QUALIFICATION NAME: ROYAL D. HEINS DATE OF BIRTH: July
14, 1953 ACADEMIC RANK: Professor DEGREES: B. S. Colorado State University
1975 Ph.D. University of Minnesota 1978 DATE JOINED MSU FACULTY: July 1,
1978 HONORS AND AWARDS: Phi Kappa Phi, Colorado State University - 1975
Pi Alpha Xi, Colorado State University - 1975 Gamma Sigma Delta, Colorado
State University - 1975 The Kenneth Post Award, American Society for Horticultural
Sciences - 1980 Sigma Xi, Michigan State University - 1988 Futura Award,
Bedding Plants, Inc. - 1988 The Alex Laurie Award, The Ohio Florists’ Association
- 1989
ACADEMIC RESPONSIBILITIES: 75% Research, 25% Teaching
ORGANIZATIONAL MEMBERSHIPS:
American Society for Horticultural Sciences International Society of
Horticultural Sciences American Society of Plant Physiologists Sigma Xi
(Science honorary) Gamma Sigma Delta (Agricultural honorary) Pi Alpha Xi
(Floriculture honorary) NCR 101 Controlled Environment Working Group Ohio
Florists’ Association Professional Plant Growers Association
EXPERIENCE CAPSULE:
Royal Heins has been on the staff of Michigan State University since
1978 when he was hired as an Assistant Professor to teach and conduct research
in floriculture physiology. He was promoted to Associate Professor in 1983
and Professor in 1988. He was born in Nebraska, grew up in Colorado, received
his B.S. degree in 1975 from Colorado State University and his Ph.D. three
years later in 1978 from the University of Minnesota.
At Michigan State University, Dr. Heins teaches part of a greenhouse
management course and the course on production of flowering potted plants.
He advises both undergraduate students and graduate Masters and Ph.D. students.
He has an active research program studying the physiology of flowering
potted and bedding plants. Four students have received their Masters degree
and 3 students their Ph.D with Dr. Heins as their thesis advisor.
Dr. Heins has authored or co-authored 56 scientific articles and 130
extension and grower articles. He has spoken at over 100 grower meetings
and 15 scientific meetings.
RESEARCH ACCOMPLISHMENTS OF STUDENTS IN PAST FIVE YEARS:
Developed commercial recommendations for methods of mixing and applying
silver thiosulfate to flowering plants, especially geranium, for the prevention
of flower petal abscission. Showed the application of silver thiosulfate
to geraniums infected with Pythium but appearing healthy caused the death
of the plant due to the Pythium. Determined fungicidal recommendations
to prevent the plant death.
Modeled the growth and development of several flowering plants including
chrysanthemum, poinsettia, Easter lily, Hibiscus, and African violet. From
the modeling research on chrysanthemum and Easter lily, determined that
the DIFerence between day temperature and night temperature (DIF = DT -
NT) strongly controlled stem elongation in most plants. The use of the
DIF concept is now gaining wide acceptance as a method to control height
of flowering plants either without the use of growth regulators or with
minimal use. Determined the optimal temperatures for flower development
in chrysanthemum is between 65 and 70′F. Exceeding 70′F slows plant development.
This information is especially critical on Valentine’s Day and early Easter
crops where light limits rate of development. Increasing temperature above
70′F on these crops delays development instead of promoting rate of development.
Determined that leaf unfolding in the Easter lily was a linear function
of average daily temperature in the temperature range of 50 to 85′F. This
information is being used in combination with the DIF concept to accurately
time Easter lilies while controlling plant height. Determined that the
type of pinch given a poinsettia influences initial rate of stem elongation
and final plant characteristics. Lateral shoots on plants given a soft
pinch (roll out type of pinch) initially develop slower than lateral shoots
on plants given a hard pinch or a soft pinch with the immature leaves being
removed. The final appearance of plants at flower given a soft pinch is
tall and upright in comparison to hard pinched or soft pinched, immature
leaf removal plants where plants are shorter and broader.
Developed a mathematical function describing stem elongation in poinsettia
and chrysanthemum from pinch to flower. This model was developed into a
grower management tool called graphical tracking. In graphical tracking,
actual plant height is plotted against predicted plant height. DIF and
growth regulators are modified as needed to keep the actual plant height
near the predicted plant height so plants finish within a window of specified
heights. A similar relationship for Easter lily elongation has been developed
from emergence to flower. The use of graphical tracking of Easter lilies
is now becoming common.
