Abstract:
The effects of planting date on mineral element
concentration in sweet corn (Zea mays L. cv. Jubilee) at six
developmental stages and on yield were investigated.
Planting dates were chosen to correspond to early,
mid-season, and late commercial plantings. Two nitrogen
rates were applied since nitrogen is more often limiting
than any other nutrient for sweet corn grown in Western
Oregon. Boron was also applied since it has been shown to
be limiting in many other crops grown in the Willamette
Valley.
Planting date significantly affected N, P, K, Ca, Mg,
Mn, Fe, Cu, B, and Zn concentration in the whole plants
during the vegetative growth stages and in the ear leaves
during the stages between tasseling and harvest. During the
early stage of growth, N, P, K, Ca, Mg, B, and Zn tended to
be higher in the early planted corn plants, while later in
the development of corn the effects of planting date were
more variable. Planting date also affected the fresh and
dry weight of whole plants; the later planting produced more
dry weight than the earlier two plantings, while the early
planted corn produced more fresh weight at harvest than the
later two plantings. Consequently, when analyzing sweet
corn for nutritional status, date of planting should be
considered when interpreting the plant analysis data.
The application of B had no effect on yield, fresh
weight or dry weight and only increased B concentration at
the first developmental stage. The additional application
of N, did not significantly increase yield for the late
planted corn, but did for early planted corn. N
concentration, as well as Mg, Mn, Cu, and Zn concentrations
increased with the higher rate of N fertilizer applied (125
kg/ha). Fresh weight and dry weight were both higher in the
plants receiving the higher rate of N, with the difference
becoming greater as the plants matured.
