The nutrient elements needed for the optimum
growth and yield of pear trees is vitally important to the
pear growers. The knowledge of the amounts and kinds of
fertilizer to apply to obtain this growth could increase
the production and cut the costs for these growers.
Field experiments have been made on the nutritional
elements needed for pears, but the results were
affected by many variants, such as the availability of
the elements and rainfall. The growing of fruit trees in
sand with controlled nutrient solutions added had been
used to obtain data not possible to obtain under field
conditions. Since other factors affect the absorption
of the nutrient elements in the field experiments, an
experiment for the application of varied nutrient solutions
on one year old Anjou pear trees, grown in sand
culture, was undertaken. The purpose was to try to
determine the influence that the concentration and the
ratio of nitrogen and phosphorus in the nutrient solutions
would have on the amount of nitrogen and phosphorus
which the pear trees would absorb into the leaves.
One year old pear trees were grown in a sand
culture in a greenhouse through one growth period. The
experiment was set up as a factrial with three levels
each of nitrogen and phosphorus. The solutions were
applied through an automatic system which irrigated
the trees every hour. The solutions were checked daily
and were changed once every week. The trees were harvested
and the leaves were analyzed for nitrogen and
phosphorus.
The results indicated that the supply of nitrogen
was adequate at all levels to support normal development
of the leaves of the trees. The supply of nitrogen in
the nutrient solution did not cause the percent of
nitrogen in the leaves to vary by a statistically significant amount.
The analysis of the variations of the percent of
phosphorus in the leaves showed significant differences
between treatments. The main effect of the phosphorus
in the nutrient solution was to increase the phosphorus
content of the leaves as the supply of phosphorus was
increased. The main effect of phosphorus on nitrogen
was negative at all levels. This effect was noticeable
at the highest phosphorus level, but it was not statistically
significant.
The ability of the Anjou pear tree, to absorb
both nitrogen and phosphorus from a nutrient solution
with very low levels of each of the elements, implies
that heavy fertilization with either of these elements
may not be necessary for normal, vigorous growth; this
is especially true in the case of phosphorus. / Graduation date: 1960
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27001 |
| Date | 27 April 1960 |
| Creators | Smith, Vernon Norman |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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