| Summary: | A two year field experiment was carried out in Delta Municipality, British
Columbia. The study was designed to investigate the effects of dates of underseeding
different cover crops such as crimson, red clover and alsike clovers and annual ryegrass
and fall rye with sweet com. The experiment was conducted as a split plot, randomized
complete block design with 12 treatment combinations and four replicates. Main plots
were the two dates of cover crop planting, one shortly after emergence and the second
at side dressing time (~ 30 cm). Subplots were comprised of an unseeded control plus five
different cover crops seeded under sweet com.
In the 1992-1993 and 1993-1994 growing seasons, the effects of cover crops on
fresh arid dry cob yield of sweet com were not significant. In the 1992-1993 experiment
the type of underseeded cover crops had no effect on either fresh or dry stalk yield,
while in the 1993-1994 growing season stalk yields were reduced by fall rye and annual
ryegrass relative to red clover. Early planting of cover crops significantly reduced the
fresh and dry stalk yield of sweet com.
There were no differences due to cover crops in the com ear leaf nitrogen
concentration in the 1992-1993 growing season. However, in the 1993-1994 growing
season, sweet com/fall rye had significantly lower ear leaf nitrogen concentrations than
sweet com/red clover. In the 1993-1994 growing season the ear leaf nitrogen
concentrations of early underseeded sweet com were significantly lower than ear leaf
nitrogen concentration of late underseeded sweet corn.
In the 1992-1993 growing season, red clover produced the highest cover crop dry
matter yield. Nitrogen concentrations in alsike and red clovers were higher than that of
annual ryegrass. In 1993-1994 growing season, crimson clover produced the highest dry
matter yield. The nitrogen content of crimson clover was higher than that of alsike
clover, fall rye and annual ryegrass in that year. In both 1992-1993 and 1993-1994
growing seasons, annual ryegrass had the highest percent cover compared to the other
treatments.
Fresh and dry cob yields of sweet corn were not affected by date of seeding nor
type of cover crop underseeded. Early underseeded cover crop appeared to compete with
sweet corn for nitrogen as compared to late underseeding. Despite low dry matter
production which may be attributed to different growth habits, annual ryegrass and alsike
clover look promising soil cover crops because they gave higher percentage of soil cover.
|
|---|
