Vol. 51—1997 - NorthEastern Weed Science Society

88
Managing
nterseeded Cover Crops in Potatoes by Varying Seeding Rate and Placement
R. Rajalahti* and R R. Bellinder, Cornell University, Ithaca, NY.
Inters ded cover crops have shown potential to suppress weeds in several crops. Field
studies we e conducted in 1995 and 1996 to evaluate potential weed suppression with two cover
crop place ent techniques (broadcast and strip-plant) and two seeding rates of hairy vetch (23
and 46 kg a), oats (36 and 72 kg/ha), and red clover (7 and 14 kg/ha) to suppress in-season
weeds in otatoes. All cover crops were interseeded following hilling 5 weeks after planting
(WAP). over crops and weeds were regulated with fluazifop (0.22 kg ai/ha) and metribuzin
(0.28 kg a) as-needed. Treatments were compared to bareground and to a chemical standard,
metolachl r (1.7 kg ailha) and linuron (1.7 kg ai/ha), applied PRE. In both years, the chemical
standard ovided best weed control, however, differences were not significant. In neither year
did cover rop seed placement technique or seeding rate affect weed controL In a dry season
(1995), re ulated grasses provided better weed suppression than unregulated legumes. In 1996, a
season wi adequate precipitation, when cover crops were not regulated, legumes tended to
provide tter weed suppression than grasses. Yield differences were not significant in either
year. Ho ever, in general, yields with broadcasting tended to be greater than with strip-planting,
and yiel with lower seeding rates greater than with higher rates. In 1995, yield with grasses
were bett r than with legumes, but in 1996, differences between cover crops were not significant.
Thus, nei er cover crop placement or seeding rate affected weed suppression. Yield, however,
was redu by higher cover crop seeding rates.
Key wor s: potato, interseeding, cover crops, competition, seed placement, seeding rate