|Abstract or Summary
- A series of nine experiments designed to evaluate the effects
of N, P, and K fertilizers on the production of wheat in western
Oregon were seeded in the fall and carried through the 1967 growing
season. The experimental sites were selected to represent different
soils that are used for production of wheat in western Oregon.
The locations also provided a range in yields, nutrient content, test
weight and protein content of the three wheat varieties used for the
The soils of the experimental sites included two of the most
productive soils in the Willamette valley, Chehalis and Woodburn
series, and the Steiwer and Willakenzie series which represent large
areas of hill soils in western Oregon. The other selected sites
represented the Aloha, Amity, Laurelwood, Newberg and Wapato
Three wheat varieties, Druchamp, Nugaines and Gaines, were
used on the experiments in a completely randomized block design.
Treatment combinations of different rates of N, P and K fertilizers
were applied on one selected variety of winter wheat at each location.
A varietal comparison was included for which an optimum fertilizer
treatment was applied to plots of each variety.
In the fall a small amount of N plus the P and K fertilizers
were banded with the seed at plating time. A spray application of
Karmex (3-3,4 dichlorophenyl 1 methoxy 1 methylurea) was applied
immediately following seeding except for the Dromgoold site where
Karmex was sprayed prior to planting, On some but not all of the
plots a spray application of 2, 4 D (2, 4 dichlorophenoxyacetic acid)
was applied in spring to control broadleaf weeds. The major portion
of fertilizer was applied in the spring in a broadcast application.
The N, P, and K contents of plant tissue at two stages of
growth and protein content of the grain were determined in the
laboratory. Yield of grain and test weight on samples harvested
were obtained on each experimental plot. The data were statistically
analyzed, treatment means were compared and tested for relevant
The application of N increased the yield of grain and the concentration
of N, P and K in the plant tissue. The application of Nalso decreased the test weight of the grain and increased protein content
of the grain. The application of K produced no major significant
changes in any of the variables studied, but P application produced
a significant increase in grain yield at one location and somewhat
smaller increases in yield at five other locations. Absence of
response to P at some locations and K applications at essentially
all locations was probably due to the adequate levels of these nutrients
in the soil prior to treatment. The present experiments substantiated
the previous caliberations for P and K soil analyses.
Nugaines was the highest yielding variety in a majority of the
experiments when compared with either Gaines or Druchamp.
Nugaines also had a significantly greater test weight than Gaines
Druchamp had the highest protein content of the three varieties
at all locations where rates of fertilizers were comparable, but the
concentration of N in plants of the individual varieties at the jointing
stage was lowest for the Druchamp variety at all locations.
The climatic conditions in the valley during the growing season
of 1967 were unusually mild during winter and drier and warmer than
normal during the summer months. These climatic adversities probably
resulted in a below average response to the applied fertilizer.
Also competition from grass was above average. Stripe and leaf
rusts were serious problems throughout western Oregon. These
factors created conditions which undoubtedly reduced yields and
responses from fertilizer.