Atmospheric Drought Tests of Some Pasture and Turf Grasses¹

Abstract

\1 [HERE hot, dry winds blow frequently during the growmg IV season, many plants die even though soil moisture has not been reduced to the wilting point. Such desiccation of plants is called atmospheric drought and has not received as much attention as soil, or edaphic drought. Although atmospheric drought seldom affects growth and duration of grasses in the Great Lakes region, these data on atmospheric drought are submitted in the hope that they will be of interest to those concerned with the physiology and ecology of grasses. Schultz and Hayes (4) 3 in a study of atmospheric drought resistance of a number of pasture grasses and legumes by means of the artificial drought machine devised by Shirley (5) obtained results which agreed closely with field observations. Aamodt and Johnston (r) tested the effects of atmospheric drought on a number of spring wheat varieties. They found that the plants could be hardened to atmospheric drought by short exposures to either soil drought or atmospheric drought.Vassiliev (6) deems it possible to breed plants resistant to atmospheric drought but not to soil drought. MATERIALS AND METHODSGrasses included in this test were Kentucky bluegrass (Poa pratensis L.), wood meadow grass (P. nemoralis L.), Astoria bent (Agrostis tenuis L.), cocoos bent (A. tenuis L.), South German mixed bent (A. tenuis L., A. palustris L., and A. canina L.), highland bent (A. canina L.), Cliewings fescue (F. estuca rubra fallax L.), red fescue (F. rubra), sweet vernal (Anthoxanthum. odoratum L.), red top (A. alba L.), carpet grass (Axonopus compressus L.), and Bermuda grass (Cynodon dactylon L.). With the exception of Bermuda and carpet grass, all species were seeded in the fall of 1939 and had established a thick, heavy sod within a year. Bermuda and carpet grass were sown in the spring of 1941, and although good stands were secured, they did not produce as heavy sod as did the other species.One-half of each plot of the earlier seeded species was fertilized with ammonium sulfate at the rate of 5 pounds per 1,ooo square feet in April, July, and October·each year. The unfertilized and fertilized portions of the plots were designated as "lowand high-nitrogen sections", respectively. Bermuda and carpet grass remained unfertilized.The plots were located on Wooster silt loam which was in a high state of productivity.. Samples were taken the middle of September r941. A golf cup-hole cutter was used to lift plugs of sod 4?1 inches in diameter and approximately 3 inches thick 'Contribution from the Department of Agronomy, Ohio Agricultural Experiment Station, Wooster, Ohio.

Factors influencing survival of strains of ryegrass during the summer

“…Excessive death of tillers during a hot or dry spell could occur, leading to a substantial opening of the pasture and to a reduction of its productivity. The results presented support the earlier findings by Dexter (1937) and Carroll (1942) that nitrogen fertilisation during summer reduced survival of plants of various graminaceous species in U.S.…”

“…Heyne and Brunson 1940;Carroll 1942;Julander 1945;Iljin 1957). Although Levitt (1951) concluded that frost, drought (i.e.…”