Annual Forage Yield Research Articles

EFFECTS OF ANNUAL RATE AND TIMING OF N FERTILIZATION ON PRODUCTION OF TIMOTHY, BROMEGRASS, AND REED CANARYGRASS

The effects of rate and time of N fertilization in the presence of sufficient P and K on seasonal and annual forage yields were studied on timothy, bromegrass, and reed canarygrass for 4 yr. Nitrogen treatments consisted of a control (receiving no N) and two to four split applications of N at the annual rates of 169, 225 and 280 kg N/ha. The annual rates of N application increased spring production of timothy but did not affect the seasonal and annual yields of the other crops. A split application of a portion of 225 or 280 kg N/ha in early summer instead of mid-summer increased timothy production during that season. Bromegrass production in spring was increased with an early spring application of a portion of the annual N rate of 280 kg/ha. Reed canarygrass production was not affected by split treatments of N. Nitrogen fertilization reduced white clover populations in the fields of timothy and reed canarygrass and of broad-leafed weed populations in all the forage crops.

Anthracnose Resistance Increases Alfalfa Yields1

Development of high levels of anthracnose (Colletotrichura trifolii Bain) resistance in alfalfa (Medicago sativa L.) in the early 1970's stimulated interest in obtaining estimates of the increased productivity associated with resistance. This paper reports the results of forage yield trials established at 24 locations in the eastern, midwestern, and western United States. Each trial included four pairs of anthracnose‐susceptible and anthracnose‐resistant bioindicator strains: 1) Glacier and Beltsville 1‐An4, 2) Saranac and Beltsville 2‐An4, 3) Vernal and Beltsville 3‐An4, and 4) Team and Arc. Forge yields were recorded for 3 years at 18 locations and for 2 years at six locations. Average annual forage yields were significantly higher for the resistant strains than for the susceptible strains at 15 of the 24 locations, averaging 1.1 mt/ha/year (10%) greater for the resistant than for the susceptible strains. A 0.8 mt/ha/year (7%) yield advantage of resistant strains over susceptible strains was obtained over all 24 locations. These results clearly indicate the value of anthracnose‐resistant alfalfa cultivars to U,S. agriculture.

Effects of Climate on Forage Yields and Tree-Ring Widths in British Columbia

HIghlight: On forested lands (1954 to 1969) 109 annual forage yields from 12 locations were studied. Very dry springs and unusually low annual precipitation resulted in low forage yields. Dry summer months were associated with superior yields provided the past year had been wet. The relationship was not consistent, however, nor was there a consistent relationship between tree-diameter growth and climate based on monthly or seasonal temperature or precipitation records. Annual forage yields were least on the Dewdrop and highest on the East Mara ranges, 325 and 1 01 7 lb oven dry, respectively. Forage yields on open rangelands (1954 to 1969), although only moderately associated with individual values for seasonal average temperature or total precipitation, could be estimated very well by all weather variables describing a 15-month period. The 190 observations of yield from 16 open rangeland locations averaged 544 lb oven dry, with a minimum of 84 lb in 1967 and a maximum of 616 lb in 1965. Expressed as percentages of 1963 yields, annual forage weights averaged 11 6%o and ranged from 53 to 214%o. Such large variations as a result of fluctuations in climate are of obvious importance to graziers, and the possibility that forage yields can be related to long-term variations in tree growth merits further study.