Seed Mix Design Flashcards
What are the pro’s and con’s of high sowing density?
Early ground cover means weed suppression. May also suppress clover due to ryegrass establishing more quickly and having a vigorous growth habit.
What are the pros and cons of a low sowing density?
delayed ground cover to allow for more tillering and branching to be stimulated due to light reaching base of plant and clover stolons. More clover, but trade-off for more weeds.
What sowing density do we go for in Dairy and Why?
high sowing density to get adequate ground cover and paddock back into rotation quickly.
In the Harris Paper. Which ryegrass cultivars were mixed and what was the result on yield?
Manawa and Ruanui ryegrass. Manawa is an Italian hybrid cultivar, so has larger leaves per metre so was able to intercept more light than the Ruannui perennial ryegrass diploid cultivar.
Define the antagonistic effect on yield
No yield benefit
Define synergistic effect on yield
Yield benefit was seen
What is the effect on yield when mixing cultivars of the same species?
No yield benefit, just competition between the species for light.
What is the effect on yield when mixing cultivars of different species?
There is a yield benefit, they differ in their growth habits and ability to capture light so can offer benefits. Such as clover and ryegrass.
Why does mixing clover and ryegrass result in a yield benefit?
ryegrass can grow and regrow a canopy of healthy green leaves using the nitrogen that the clover has fixed and increase LAI and therefore canopy closure.
How many species were used in a seed mix back in the bush-burn stages?
over 20
What happened to yield when Manawa and Ruanui were combined in a seed mix and grazed laxly and infrequently? Why?
It has decreased, due to the outstanding of the Ruanui tillers by the Manawa tillers which grow more during Winter due to being a hybrid which killed the Ruanui so that it couldn’t increase growth in Summer.
What happened to yield when Manawa and Ruanui were combined in a seed mix and grazed closely and frequently? Why?
The ruanui became the dominant pasture grass.
