|Abstract or Summary
- Hard red winter wheat has the potential to be an alternative crop
in the Pacific Northwest, however percent grain nitrogen has been
unacceptably low and grain yields have been about only 80% of soft white
winter wheat. During the late spring and the summer months there is
usually little rainfall, therefore moisture and nitrogen needed for
grain fill must be taken up from the subsoil. The interaction between
rainfall distribution and available nitrogen and moisture at different
depths in the soil during grain fill was thought to be the problem for
low percent grain nitrogen in this mediterranean climate.
Dryland field experiments were conducted with the hard red winter
wheat cultivar Nanser' at the Sherman Branch Expeilment Station at
Moro, north-central Oregon, during the crop years 1983 and 1984. Plots
were fall-fertilized with 0 (low N) and 80 (high N) kg/ha of nitrogen
fertilizer and 0 and 20 kg/ha of phosphorus fertilizer. At jointing and
at anthesis, 0 and 20 kg/ha of nitrogen fertilizer were applied with
water, to the 0, 60 and 120 cm soil depths to determine the effects upon
percent grain nitrogen, grain yield, plant nitrogen yield and nitrogen
harvest index (NHI) at harvest.
The 80 kg/ha fall-applied N rate was the factor most responsible
for increasing percent grain nitrogen and grain nitrogen yield. Grain
yield was increased only in 1984.
Under low N fertility conditions, percent grain nitrogen was
increased by the 20 kg/ha N rate applied at anthesis in 1983. Grain
yield was increased with the 20 kg/ha N rate applied at jointing, both
years, and was limited if phosphorus fertilizer was not present with the
anthesis timing in 1983. Grain nitrogen yield was increased by P
fertilizer and the 20 N rate (regardless of timing) in 1983, and when N
was applied at jointing in 1984.
Under high N fertility conditions, 20 N rate applied at jointing
increased percent grain N both years, and grain nitrogen yield in 1983.
Grain yield was not increased.
In general, percent grain N in the high N fertility plots and the
1984 low N fertility plots was positively correlated to the nitrogen
yield of all the plant parts, except chaff in 1984. Percent grain N was
negatively correlated to grain NHI under high N fertility conditions,
but positively correlated under 1983 low N conditions. Percent grain N
was positively correlated to most other plant parts' NHI under high N
fertility conditions in 1983 and 1984 and 1984 low N fertility
conditions. Under low N fertility conditions in 1983, percent grain N
was positively correlated to grain NHI.
Deep placement did not significantly increase percent grain N,
grain yield or grain nitrogen yield. Under high N fertility conditions
in 1984, more nitrogen remained in some of the straw plant parts at the
60 cm depth with the anthesis timing compared to jointing.