|
|
TEACHING: PLANT NUTRITION:
SPECIAL RESEARCH PROJECT |
|
|
This section includes the final project reports
of research done by each student in the 2005 Fall Semester class of
Plant Nutrition. Each of these reports has been peer reviewed by Bruce
Bugbee and Julie Chard and accepted for publication on this web site.
Each manuscript reports the results of original research. Many have
fascinating findings that warrant further investigation. For
additional details please contact the authors.
|
|
|
|
|
 |
ABSTRACT Proper
nitrogen application is important since optimal nitrogen levels vary
for each species. Knowing the optimal concentration of nitrogen to
use for a specific turfgrass could help reduce input in turf
management. The purpose of this study was to see if the recommended
rate of a commercial slow-release fertilizer (Osmocote) is ideal for
multiple grass species, and to determine the effect of different
fertilizer concentrations on different species. Six grasses were used
in the study: bermudagrass (Cynodon dactylon [L.] Pers.,
warm-season), buffalograss (Buchloe dactyloides [Nutt.] Engelm.,
warm-season), Crested wheatgrass (Agropyron cristatum [L.]
Gaertner, cool-season), Tall fescue (Festuca arundinaceae
Schreb., cool-season), Fine fescue (Festuca rubra L.,
cool-season), and Sandberg bluegrass (Poa secunda J.S. Presl,
cool-season). Five Osmocote concentrations were used in the study;
they were a percent of the recommended label rate: 100, 50, 25, 12.5
and 0% (175, 87.5, 43.75, 21.875, and 0 g N). Five tubs filled with
70% sand and 30% peat were used, each tub represented a different
Osmocote concentration. Each tub was divided into six plots, one plot
per species. Fresh root length, dry clipping mass, dry shoot:root
ratio, and percent dry root mass were all analyzed. The results
suggest that the Osmocote concentration amounts greater than 12.5%
were too high for bermudagrass, Crested wheatgrass, Tall fescue, and
buffalograss. Overall, the study did show that the recommended label
rate used was not the ideal nitrogen concentration for any of the six
grass species. Nitrogen concentrations between 12.5 and 25% were best
for Fine fescue, and 0 and 25% were best for Sandberg bluegrass.
However, both Fine fescue and Sandberg bluegrass did well on all five
concentrations.
|
|
-
Determining Nitrogen Fixation Levels in previously nodulated
Alnus maritima plants using a commercial slow release fertilizer
as a nitrogen source
Taun Beddes (tbeddes@yahoo.com)
|
|
|
ABSTRACT
Alnus maritim is an
endangered species that shows potential for use in the landscape,
because it has the ability to fix its own N from the air by way of
Frankia bacteria in root nodules. This study was conducted
to determine if a commercially available, 3-4 month slow release
fertilizer would inhibit N-fixation and further nodulation in these
plants. If the alders were able to do so, chances of survival when
out-planted would increase and N fertilizer would not need to be
applied to them, thus helping the environment. Plants were grown
under greenhouse conditions and fertilized at rates ranging from
0.0-32.0 g fertilizer. The experiment lasted for 20 days and data
was collected by measuring root and stem/leaf dry weights and
counting nodules. There was a marked increase in nodule numbers per
plant from the beginning to the end of the experiment. This
increase may suggest that N-fixation was occurring. Further, plants
grown at lower rates of fertilizer grew almost as much as those
grown at higher rates, which may also suggest that N-fixation
occurred due to the similar growth rates.
|
|
|
|
|
 |
ABSTRACT Root depth of turfgrasses is important in nutrient acquisition and drought
resistance. Four grasses; Poa pratensis (Kentucky bluegrass),
Bouteloua gracilis (blue grama), Festuca ovina (sheep
fescue), and Pascopyrum smithii (western wheatgrass) were grown
in a greenhouse with automated watering with a full nutrient solution
for 63 days in 45 cm columns filled with Turface to evaluate root
growth potential. Western wheatgrass and blue grama roots reached 45
cm in 45 days. Kentucky bluegrass roots had lengths of 37 cm in each
of the 2 columns and sheep fescue had an average of 33.5 cm. Grasses
with the deepest roots had the highest fresh and dry mass.
|
|
|
|
|
 |
ABSTRACT Peat is an organic matter that improves soil properties. Varying
the amount of peat in a peat/sand mixture alters the crop biomass as
well as the root: shoot ratio. This study was done to examine how
different levels of peat in sand alter the growth of Abby bluegrass
and field corn. Columns of five sand/peat mixes ranging from 0%-60%
peat were tested with two replicates of each. Abby bluegrass and corn
both produced more biomass with 35% peat then any other combination.
Root mass was the highest in 0% peat. These results indicate that the
normal “golden ratio” of only 10% peat is inadequate to support
optimal growth in a golf green.
|
|
|
|
|
 |
ABSTRACT Crop yields can be reduced by different types of cultivation before
planting. This greenhouse study examined the effect of bulk density
(compaction) on growth. Corn with three replications at each of
three bulk densities (1.15, 1.30, 1.45 g/cm3) was grown
in soil columns for 49 days in a sandy loam. Shoot and root dry
weight and root length were measured. Root mass and length
decreased as the bulk density increased. Compaction of the soil had
a minimal effect on shoot growth. Shoot mass was not significantly
different among the treatments. Root mean length was different
among the different treatments 45.2 m 36.3 m 32.5 m respectively.
Root weight was also different at 1.93 kg, 1.47kg, and 0.9kg
respectively. Lower bulk density increased root growth and may
increase yield in water or nutrient stressed environments.
|
|
-
Effect of Nutrient Supplements on Cowpea Nodulation
Sallee Reynolds
|
|
|
ABSTRACT Little is
known about ideal conditions for initiation of biological nitrogen
fixation. It has been shown that field cropping history, nitrogen
availability, and soil condition play a major role in nodulation.
It is thought that some nitrogen increases nodulation but that too
much inhibits it. This study examined the nodulation response of cow
pea (Vigna unguiculata) to nutrient supplement. Plants were
grown in tap water, tap water with a 10% concentration of slow
release fertilizer, and Peter’s Complete Nutrient Solution. Groups
of those grown in nutrient solution were moved to tap water after
35, and 45 days. Plants were destructively harvested at 35, 45 and
55 days after planting. On a logarithmic scale, the data for number
of nodules formed were normal and showed a statistical difference
between the number of nodules per harvest (p=.018) but did not show
statistical difference between nutrient levels (p=.08). The weight
data for this project showed normal data that was statistically
different between harvests (p=.003) but not statistically different
for nutrient levels (p=.268). These non-significant results could
have been caused by a confounding factor that the plants watered
with nutrient solution were compromised due to drought stress
experienced at two different times during the study.
|
|
|
-
Effect of Ionic
and Osmotic Stress on Lettuce, Radish, and Crested Wheatgrass
Ruth Richards (ruth@cc.usu.edu)
|
|
|
ABSTRACT Soil salinity
and drought reduce yields in agricultural systems. Plants that use
water efficiently can produce high yields in water limited
environments. Seed germination is a critical point in seedling
establishment and subsequent plant health and vigor. The purpose of
this study is to determine the effects of three solutes on seed
germination. Three species were chosen based on relative salt
sensitivities. Radish (Raphanus sativus) is categorized as a salt
sensitive species. Lettuce (Lactuca
sativa L.) is a moderately salt tolerant species. Crested
wheatgrass (Agropyron desertorum) is a high salt tolerant species
(USDA, 1954). A completely randomized design was used. The first
factor (species) had three levels (radish, lettuce or crested
wheatgrass), the second factor (solute) had three levels (NaCl, CaCl2,
PEG). The third factor (osmotic potential) had two levels (-0.46
and -1.37 MPa). The final germination percentage was analyzed using
analysis of variance (ANOVA) in Statistical Analysis System (SAS
9.0) The ionic stress trials at higher osmotic potentials (-0.46)
showed that lettuce is more salt tolerant than radish. At the lower
osmotic potential (-1.37), radish appears to be more
tolerant of both NaCl and CaCl2 treatments. No lettuce
seed germinated at any level of PEG. The percent germination for
Radish seeds in PEG is not significantly different from zero.
Crested wheatgrass showed less salt tolerance for the higher osmotic
potential of NaCl than lettuce or radish but more salt tolerance at
the lower osmotic potential of NaCl than radish. Crested wheatgrass
showed the most tolerance to PEG in the -0.46 MPa trial. No seeds
of radish, lettuce or crested wheatgrass germinated in -1.37 MPa
PEG.
|
|
|
|
|
 |
ABSTRACT Root
architecture describes root growth over time and space. Prior studies
have examined the effects of ethylene and nutrient deficiency using
ethylene precursors or inhibitors in combination with nutrient
deficiency. To test if ethylene gas alone could alter root
architecture in young pea plants, a 30 ppb flux of ethylene was
maintained through a column root zone. Although not statistically
significant, the data trend shows that roots grown without ethylene
were longer, had more lateral branches, and supported larger shoots.
This is contrary to literature that shows ethylene induces root growth
under nutrient deficiency.
|
|
-
Influence of Humic Substances on
Irrigation Frequency and Phosphate Absorption of Creeping Bentgrass
Putting Greens
Adam
Van Dyke (avandyke@cc.usu.edu)
|
|
 |
ABSTRACT Humic
substances (HS) reportedly enhance moisture retention of soil.
However, no information is available as to the effects of HS on
sand-based golf course putting greens. HS have acidic functional
groups (COOH) that are reaction sites on the molecule. An greenhouse
experiment was conducted to evaluate the effect that the acidic
functional groups in humic acid, tannic acid and citric acid have on
the volumetric water content of sand, and the phosphorus (P) content
of ‘Dominant’ creeping bentgrass (Agrostis palustris L.).
Bentgrass plugs were grown in calcareous sand and irrigated with 250
mg L-1 C solutions
of each of the organic acid products. Irrigation occurred when the
volumetric water content of the soil reached 5%. Soil moisture was
measured with a HydroSense® water content sensor for 3 months.
Phosphate was added as KH2PO4 at 50 kg·ha-1
2 months into the experiment. The irrigation interval was longer
between watering for humic acid, but rarely differed between the
treatments. Daily soil moisture percentage following irrigation with
all organic acid treatments was different from the control, with humic
acid retaining moisture longer on average. Humic acid, tannic acid,
and citric acid increased tissue concentrations of P, with tannic acid
having the highest percent increase. Further research is necessary to
evaluate the residual effects the organic acids may have on longevity
in the soil.
|
|
FINAL REPORTS: 2006
