Source: UNIVERSITY OF NEBRASKA submitted to
EXPLORING PLANT NUTRIENT INTERACTIONS IN FLORICULTURAL AND ORNAMENTAL CROPS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0181126
Grant No.
(N/A)
Project No.
NEB-20-062
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Dec 2, 1998
Project End Date
Nov 30, 2003
Grant Year
(N/A)
Project Director
Paparozzi, E. T.
Recipient Organization
UNIVERSITY OF NEBRASKA
(N/A)
LINCOLN,NE 68583
Performing Department
AGRONOMY & HORTICULTURE
Non Technical Summary
There is an economical and industrial need to look at the interaction of many plant growth factors at a number of rates to understand plant growth responses such as leaf yellowing. This project looks at novel experimental desings and analyses that will better model multiple nutrient interaction effects on plant growth. Yellowing of leaves is a symptom of nutrient deficiency produced by a number of elements. This study will explore, biochemically, nitrogen, sulfur, iron and manganese interactions and the expression of yellowing.
Animal Health Component
50%
Research Effort Categories
Basic
25%
Applied
50%
Developmental
25%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1022122101035%
1022129101030%
1027310101020%
9017310101015%
Goals / Objectives
1. Identify plant growth and developmental changes due to the nitrogen sulfur interaction when growers modify their fertilization strategies. 2. Investigate leaf yellowing and reduced growth due to plant nutrient interactions, particularly low levels of S in combination with adequate fertilizer levels of N. 3. Utilize plant nutrition experiments to develop statistical models, designs and methods of analysis which will better describe multifactor interactions which typify plant growth.
Project Methods
1. Conduct NS experiments in soilless mix with hydrangea. Evaluate alternative S application methods. 2. Microscopically investigate Sversus N deficiency in poinsettia. Biochemically investigate NS effects on Rubisco and possibly other proteins. 3. Develop multi-factor extensions of non-linear models using plant nutrition data.

Progress 12/02/98 to 11/30/03

Outputs
Many plant responses to applied nutrients, other than nitrogen are neither linear nor quadratic and thus, do not fit traditional polynomial regression equations well. Additionally, nutrients do not act alone, but in combination with each other. We have devised a new statistical tool that: 1) allow more accurate modeling of nutrient-response relationships in plants 2) simultaneous study of several treatment factors 3) use of designs that minimize ther required number of experimental units. This tool uses the Hoerl model with an unreplicated response surface design. It can be augmented by replication at strategically selected treatment combinations. The Hoerl model is better suited for experiments where the objective is to explore higher-order interactions, e. .g among four factors (such as nitrogen, sulfur, iron and manganese fertilizer applications) each at multiple levels such as low, medium and high rates of fertilizer applied. We found that the model does a better job accounting for non-linear relationships between applied nutrients and leaf nutrient concentrations. We have used the model to detect and explain complicated 3-way interactions and run analyses capable of detecting and helping understand 4-way interactions, if present. Thus, this provides an analysis that will account for, but is not limited to 3-way interactions among nutrient levels. This model and design together also provide a less expensive means for running a plant nutrition experiment. For example, in a 4-factor experiment, it is 66-75% less expensive in terms of labor, materials and plant analyses costs than running the traditional completely replicated full factorial design. In related crop production research, we also have demonstrated on a practical level that when growers apply half the recommended rate nitrogen in combination with low rates of sulfur, pot plant marketing quality and post-harvest floral longevity are preserved. The grower method of acidulating water and nutrient solutions with sulfuric acid will supply plenty of sulfur, but will leave sulfur in the mix. Multiple supplemental applications of sulfur via magnesium or potassium sulfate will also have a similar result, but there will be less S left in the mix. For the greenhouse industry this means that different methods of sulfur application will work equally well in supplying enough sulfur for plants without compromising floral quality or longevity. However, if there are concerns about sulfur remaining in mixes that are disposed of in a landfill (as sulfate is as leachable as nitrate), then injecting sulfuric acid into the fertilizer water is not the best method.

Impacts
This research provides an analysis that will account for, but is not limited to 3-way interactions among nutrient levels. This model and design together also provide a less expensive means for running a plant nutrition experiment. For example, in a 4-factor experiment, it is 66-75% less expensive in terms of labor, materials and plant analyses costs than running the traditional completely replicated full factorial design. For the greenhouse industry the sulfur application research means that different methods of sulfur application will work equally well in supplying enough sulfur for plants without compromising floral quality or longevity. However, if there are concerns about sulfur remaining in mixes that are disposed of in a landfill (as sulfate is as leachable as nitrate), then injecting sulfuric acid into the fertilizer water is not the best method.

Publications

  • See all individual reports 2004


Progress 10/01/02 to 09/30/03

Outputs
Many plant responses to applied nutrients, other than nitrogen are neither linear nor quadratic and thus, do not fit traditional polynomial regression equations well. Additionally, nutrients do not act alone, but in combination with each other. We have devised a new statistical tool that: 1) allow more accurate modeling of nutrient-response relationships in plants 2) simultaneous study of several treatment factors 3) use of designs that minimize ther required number of experimental units. This tool uses the Hoerl model with an unreplicated response surface design. It can be augmented by replication at strategically selected treatment combinations. The Hoerl model is better suited for experiments where the objective is to explore higher-order interactions, e. .g among four factors (such as nitrogen, sulfur, iron and manganese fertilizer applications) each at multiple levels such as low, medium and high rates of fertilizer applied. We found that the model does a better job accounting for non-linear relationships between applied nutrients and leaf nutrient concentrations. We have used the model to detect and explain complicated 3-way interactions and run analyses capable of detecting and helping understand 4-way interactions, if present. In related crop production research, we also have demonstrated on a practical level that when growers apply half the recommended rate nitrogen in combination with low rates of sulfur, pot plant marketing quality and post-harvest floral longevity are preserved. The grower method of acidulating water and nutrient solutions with sulfuric acid will supply plenty of sulfur, but will leave sulfur in the mix. Multiple supplemental applications of sulfur via magnesium or potassium sulfate will also have a similar result, but there will be less S left in the mix. For the greenhouse industry this means that different methods of sulfur application will work equally well in supplying enough sulfur for plants without compromising floral quality or longevity. However, if there are concerns about sulfur remaining in mixes that are disposed of in a landfill (as sulfate is as leachable as nitrate), then injecting sulfuric acid into the fertilizer water is not the best method.

Impacts
This research provides an analysis that will account for, but is not limited to 3-way interactions among nutrient levels. This model and design together also provide a less expensive means for running a plant nutrition experiment. For example, in a 4-factor experiment, it is 66-75% less expensive in terms of labor, materials and plant analyses costs than running the traditional completely replicated full factorial design. For the greenhouse industry the sulfur application research means that different methods of sulfur application will work equally well in supplying enough sulfur for plants without compromising floral quality or longevity. However, if there are concerns about sulfur remaining in mixes that are disposed of in a landfill (as sulfate is as leachable as nitrate), then injecting sulfuric acid into the fertilizer water is not the best method.

Publications

  • Paparozzi, E. T. 2003. Nutrition of floricultural crops: How far have we come? HortScience 38:1031-1035.
  • Thomas, D. M. and E. T. Paparozzi. 2004. Effect of chelates versus ionic salts of microelements and nitrogen form on hydroponic solution pH. J. Plant Nutrition 27: in press.


Progress 10/01/01 to 09/30/02

Outputs
In analyzing the visual and quantitative data from two four-way nutrient interaction and deficiency experiments, it became clear that when more than one element was deficient the symptomology (leaf yellowing) overlapped and was no longer indicative of the deficient elements. We found this intriguing and started asking questions such as: is there a common denominator that triggers leaf yellowing? Is there an overriding mechanism? Many nutrient deficiencies as well as other stresses are expressed as leaf yellowing. Sometimes when corrective applications of nutrients are made, leaves recover and regreen. Sometimes they do not. To help answer this question, this past year, we have created a model plant system. This hydroponic growing system allows us to monitor and reverse leaf yellowing in a given leaf of Plectranthus. Photosynthesis measurements and visualizations/photographs of chloroplasts taken with the scanning laser confocal microscope have been collected and we are in the process of interpreting this data. We hope to use this model system to understand some of the more basic mechanisms involved in leaf yellowing reversal and senescence.

Impacts
This model plant system is the first step towards linking basic molecular research on chloroplasts and leaf senescence with a whole plant in which leaf yellowing can be controlled. The ability to reverse leaf yellowing/senescence in pre-programmed senescent crops such as corn and soybeans is critical to increased yields.

Publications

  • Moreno-Sotomayor, A., A. Weiss, E. T. Paparozzi and T. J. Arkebauer. 2002. Leaf anatomy and light response curves of field grown maize as a function of age and nitrogen status. J. Plant Physiology 159(8):819-826.
  • Thomas, D. and E. T. Paparozzi. 2002. Effects of chelates versus ionic salts of microelements on hydroponic solution pH. XXVIth International Horticultural Congress. P. 488.
  • Paparozzi, E. T., M. E. Conley and L.M. Rock. 2002. Defining the role of the chloroplast in non-senescing leaves. XXVIth International Horticultural Congress. P. 492.


Progress 10/01/00 to 09/30/01

Outputs
This past year, our statistical research included testing a new non-linear model called the Hoerl model. After hundreds of simulations, we have determined that the Hoerl model provides a more robust alternative when standard response surface models or the Gompertz and Mitscherlich non-linear models fail to fit. The Hoerl model has also provided the basis for a versatile strategy for designing usable and efficient multiple factor experiments. Research involving the discreet applications of sulfur using magnesium or potassium sulfate versus continuous sulfur application via sulfur acid has been completed. The continuous sulfur application produced plants that had the highest sulfur and nitrogen concentration in their leaves as well as the best overall plant growth and flowering. Plants receiving multiple applications of sulfur as either magnesium or potassium sulfate were also of saleable quality, but had less nitrogen and sulfur in their leaves. Thus, growers using sulfuric acid at a concentration of at least 10 ppm sulfur to acidify their water will not only lower the pH, but provide sufficient sulfur to optimize the use of nitrogen applied. In these experiments it was also shown, once again, that the amount of nitrogen can be reduced when sulfur is applied. An interesting side note is that when the growing media from plants receiving the discreet applications of sulfur were analyzed, there was less residual nitrogen and sulfur. Thus, in areas where there are concerns about discards into landfills or where recycling of growing media is important, the discreet applications of sulfur would be a better method than the continuous sulfur application.

Impacts
Impact - growers can acidify alkaline water and provide adequate sulfur in one step by using sulfuric acid instead of phosphoric or nitric acid. This will also allow them to reduce the amount of nitrogen fertilizer they apply. Sulfuric acid is less caustic than nitric acid and more concentrated than phosphoric (so you use less). Thus, it should be recommended to growers as the acidifier of choice. Impact - in areas where growing media is being reclaimed or there are concerns about high amounts of fertilizers in landfills, discreet applications of sulfur are better than continuous sulfur application as there will be significantly less in the growing media being discarded. Also, by applying sulfur growers can apply less nitrogen which will also lead to less residual nitrogen in discarded growing media.

Publications

  • Conley, M. E. , E. T. Paparozzi and W. W. Stroup. 2002. Leaf anatomical and nutrient concentration responses to nitrogen and sulfur applications in poinsettia. J. Plant Nutrition in press.
  • Olson, L. M., W. W. Stroup, E. T. Paparozzi and M. E. Conley. 2001. Model building in multi-factor plant nutrition experiments. Abstracts: 2001. Conference on Applied Statistics in Agriculture.
  • Kocamaz, C. and E. T. Paparozzi. 2001. The effect of sulfur source and frequency of aication on chrysanthemum growth. HortScience36 (3):541. Abstract.


Progress 10/01/98 to 09/30/99

Outputs
Two four month experiments, each set up as a 3 to the 4th factorial, have been completed. Poinsettia cultivar Freedom Red were the plants grown. The 81 treatments were combinations of nitrogen, sulfur, iron and manganese each at 3 application rates (none or very low, half the recommended rate and full rate). All plants have been photographed, harvested, separated into leaves, roots and mix for elemental analysis. For the first experiment all analyses are complete and leaf and some mix data have been compared to standard elemental concentrations in order to identify deficiencies, sufficiencies and excesses. Data have also been formatted for subsequent statistical analysis. Statistically, data from a previous two factor factorial (nitrogen and sulfur)has been reviewed and a hybrid model has been created to account for the non-linearity of the sulfur response. We are currently working on a novel three factor model which may successfully analyze part of the data from the 3 to the 4th factorial experiment.

Impacts
Creating novel experimental designs and analyses will allow us to interpret and understand higher order interaction in plant nutrition experiments. Once created these designs will save money in terms of number of experiments needed and amount of labor involved in multiple experiments.

Publications

  • Paparozzi, E. T. 1999. Nitrogen and sulfur interaction in floricultural crops. Acta hort.481:379-383.
  • Conley, M. E. and E. T. Paparozzi. 1999. Atypical responses observed in the production of Poinsettia. Int. Botanical Congress Abstr.2393 p. 692.
  • Conley and Paparozzi. 1999. Effect of nitrogen and sulfur levels on the morphology and anatomy of Poinsettia.Int. Botanical Congress Abstr. 2396 p. 692.
  • Cuppett,McVey McCluskey,Paparozzi and Parkhurst. 1999. Nitrogen and sulfur effects on leaf lettuce quality. J. Food Quality 22:363-373.
  • Landes, Stroup, Paparozzi, and Conley. 1999. Nonlinear models for multi-factor plant nutrition experiments. Abstr.Conf. Applied Statistics in Agriculture.
  • Landes, Stroup, Paparozzi, and Conley. 2000. Nonlinear models for multi-factor plant nutrition experiments. Proc. 1999 Conf. Applied Statistics in Agriculture. KSU in press.