Fall Frost Research Articles

CULTURAL PRACTICES AFFECTING MATURITY AND YIELD OF CORN (ZEA MAYS) FOR WHOLE-PLANT SILAGE IN SHORT-SEASON AREAS

The production of corn (Zea mays L.) as whole-plant silage in short-season areas is severely restricted by such factors as late planting, slow emergence, slow early growth, and delayed silking that result from cold, wet soils and low levels of accumulated heat units. Failure of the plants to reach physiological maturity results from early fall frosts. The effects of variations in planting dates, plant densities, fertilizer and manure treatments, weeds, harvest dates, and other cultural practices on the yield and maturity of silage corn are discussed.

Effect of Fall Frost on the Activity of Glyphosate on Alfalfa(Medicago sativa)and Quackgrass(Agropyron repens)

The effect of fall frost on the activity of glyphosate [N-(phosphonomethyl)glycine] on alfalfa(Medicago sativaL. ‘Vernal’) and quackgrass [Agropyron repens(L.) Beauv.] was studied in a room of the Biotron, a controlled environment facility of the University of Wisconsin, and in the field in the fall. In a Biotron time-course study, the most effective day of treatment for quackgrass control was the day after the first frost. Quackgrass plants treated the morning after frost had significantly higher uptake and translocation of glyphosate (93%, 55%) than plants treated 4 days before frost (71%, 32%) and greater translocation than plants treated 5 days after frost (24%). In the field, glyphosate was most active on quackgrass when applied the morning after the first frost of the fall. Control of quackgrass treated with 0.4 kg/ha of glyphosate increased from 10% when treated 4 days before the first frost to a maximum of 91% when treated the day of the first frost. No significant effects of frost in decreasing glyphosate toxicity to alfalfa were found. These results minimize the possibility of using this herbicide to remove quackgrass from alfalfa.

EFFECTS OF PLANTING DATE ON RAPESEED

Planting at four dates from early May to mid-June at two locations for 2 yr in central Alberta produced the highest yield of Torch from 15 May planting and Midas from 3 May planting. Planting Torch after the end of May and Midas at the end of May, or later, results in a high risk of fall frost damage.

Low Temperature Damage to Dwarf Mistletoe Fruit

Early frost damage to dwarf mistletoe (Arceuthobium sp.) fruit was observed in the field, but the intensity of cold and duration of freezing temperatures were not recorded. In a controlled environment, exposure to −3.9 °C for about 2.3 h for lodgepole pine dwarf mistletoe (A. americanum Nutt. ex Engelm.) and for 2.0–4.8 h for hemlock dwarf mistletoe (A. tsugense (Rosend.) G. N. Jones) was necessary to cause permanent damage to the fruit. Field observations indicated that early fall frosts reduced the capacity of hemlock dwarf mistletoe to disperse seeds forcibly by 95%.

Distribution of Galleta Roots and Rhizomes at Two Utah Sites

snowpacks are followed by early fall frost. In spring, the moving of cattle up to their summer range is not restricted by snow cover, but by the growth stage of poisonous larkspurs (Delphinium sp.). Duration of snow cover could influence the phenology of larkspurs, but data are not available from Black Mesa to test this hypothesis. These observations and anialyses indicate that a 10% increase in snowpack due to cloud seeding would have little, if any, immediate effect on the productivity and use of mountain grasslands.

Multiple Causation of Perennial Plant Diseases and Control by Team Effort

During the past few years reports have increased of plant diseases of multiple causation. Some examples from perennial plants in the northern temperate zone are as follows: Maple Blight has been studied by a team of workers from several departments of the University of Wisconsin (2, 3, 4, 8, 12). They conclude that the primary cause is defoliation by the Maple Web Worm, Tetralopha asperatella, and several other less important insects. The disease also has been initiated by mechanical defoliation. Important contributing causal factors are drouth or low soil moisture at critical growth periods, severe fall frosts, and possible secondary infection by the root rotting fungus, Armillaria mellea. In addition there is severe deterioration of the smaller rootlets in diseased trees. Two primary causal factors are reported for Burn Blight of Jack and Red Pine (6). These are the spittle insect, Aphrophora saratogensis and the fungus, Chilonectria cucurbitula. The spittle bug makes an avenue of entrance and serves as a mechanical vector of the fungus in addition to causing tree damage. Disease severity is also related to tree growth rates and weather.

Efficiency of Net Primary Production Based on Light Intercepted During the Growing Season

Net primary production of a 1—year—old field on the New Jersey Piedmont was 1.08 kcal/cm2 or 10% of the radiant energy (0.4—0.7 @m) intercepted by the vegetation from the last spring frost to the latest date a dominant producer reached its peak standing crop biomass; 3.8% of the energy available above the vegetation during the same period; 7.5% of the energy intercepted from the last spring frost to the first fall frost; 3.1% of the energy available above the vegetation during this period; and 1.8% of the energy available yearly. These results are among the first direct determinations of efficiency of net primary production based on interception of radiant energy under field conditions. Interception, the difference between radiant energy available above and below the vegetation, was measured with the Yellott solarimeter, whose small size made possible below—vegetation measurements with minimum disturbance to the cover. Net primary production for shoots was determined on a species basis by the short—term harvest method. Root production was estimated on a community basis by extracting roots from soil samples by a soil—dispersion and chemical flotation technique.

An Association Between Late Summer Growth Rate and Fall Frost Injury in Red Raspberries

Abstract An association has been found between late summer growth rate and the extent of fall frost injury in red raspberries. Although frost injury during the winter is quite common in Central British Columbia, the occurrence of it during the fall is rare.

SPECIES TRIALS WITH OILSEED PLANTS: II. CAMELINA

Camelina, a member of the mustard family, exceeded flax and rape in yield of seed per acre at Ottawa, Ontario, and at Fort Vermilion, Alberta. The oil content of the 10 varieties in the test ranged from 34.3 to 38.7 per cent at Ottawa and from 37.1 to 42.0 per cent at Fort Vermilion. The average fatty acid composition in percentage of methyl esters was: palmitate 5.0; stearate 2.1; behenic 1.7; palmitoleic, trace; oleic 14.8; linoleic 16.4; linolenic 36.1; eicosenoic 17.5; eicosadienoic 2.3; erucic 3.7. The seed contained 33.1 per cent protein, 9.6 per cent crude fiber, only a trace of isothiocyanate, and no thiooxazolidone.Camelina matured 3 to 4 weeks earlier than flax. This is a valuable characteristic for northern areas as it would prevent damage by early fall frost and would permit extending the northern limits of the oilseed-producing area.

Growth of Corn and Sunflowers in Relation to Climatic Conditions

1. During 1920 and 1921, a study has been made of the growth of Zea Mays and Helianthus annuus in relation to their climatic environment. The varieties used were Northwestern dent corn and Mammoth Russian sunflowers. 2. Early seedings of sunflowers were found to germinate and appear above ground sooner than the early seedings of corn, while the late seedings of both plants required about the same time for this purpose. Both were retarded by the low soil temperatures obtaining early in the season, but the corn to a greater degree than the sunflowers. 3. A temperature of 29⚬ F. in the spring of 1920 injured the corn but did not affect the sunflowers. In 1921 a temperature of 24⚬ F. killed the corn and slightly injured the sunflowers. 4. Because of resistance to late spring and early fall frosts, sunflowers have a longer growing season than corn. 5. An effort has been made to correlate the growth of corn and sunflowers with five temperature efficiency indices used by Livingston and Shreve, as well as with de...