Observations on the Effect of Artificial Flooding on Certain Herbage Plants

Abstract

The pre-war acreage of meadowland adjacent to streams and rivers in England was estiniated at approximately 390,000 acres (1). Much of it was on aUuvial soils of good fertility. The herbage was not of a high standard and progressive farmers, encouraged by their Committees, found that the production of such rich soils could be greatly increased by ploughing and reseeding. Although the danger of prolonged flooding was appreciated, the national need for increased production and the policy of cleaning out ditches, brooks and small streams and dredging rivers, were good reasons for carrying out the work. Even in normal winters some large, rivers regularly overflow their banks with no apparent damage to existing permanent swards containing Agrostis, Holcus, red fescue, small amounts of ryegrass, cocksfoot, timothy, meadow fescue and meadow foxtail and a variety of miscellaneous species chiefly Ranunculus. The usual run of leys based on perennial ryegrass, cocksfoot, timothy, red and white clover, will withstand such flooding if it is neither too prolonged nor too deep. Occasionally, however, they are killed, even in places adjacent to old turfs containing small amounts of ryegrass, which survives.The following pilot experiments were set up in an attempt to find a mixture able to survive prolonged flooding.Turfs cut from established leys of certain grass and clover species were placed in ammunition tanks with capacity of approximately one cubic foot; these were fitted near the top with inlet and outlet pipes and connected to the mains water supply. Each species was subjected to four depths of flooding, ranging from 1 to 6 inches : each series included a sward with a high water table and one with stagnant water. Plate I shows a typical arrangement and details are given in the plan. The swards illustrated had been inundated for eight weeks and the eflfects of different depths of flooding on the various species are clearly shown. Plate II shows in greater detail the swards of meadow fescue and timothy.Bolton and McKenzie (2) comparing the resistance of certain grass and legume species to spring flooding, showed that timothy and Phalaris were not severely effected by seven weeks under 12-18 inches of water. Jones (3) states that observations in 1946 showed that timothy, both S.48 and S.50, tall fescue,-alsike, meadow fescue, creeping red fescue and wild white clover are fairly resistant to flooding. Roscveare (4) reporting on flooding in Germany, found that both timothy and meadow fescue were killed by prolonged spring flooding whilst Phalaris arundinacea was resistant to flood damage.Estabhshed swards containing the following species were used in these pilot experiments :-ryegrass S.23, timothy S.48 and S.50, cocksfoot S.37, meadow fescue S.215 and S.53, Agropyron, Agrostis, red fescue S.59, meadow foxtail S.55, white clovers S.IOO, S.I84 and certified New Zealand. 63

Influence of Water Temperature on Submersion Tolerance of Four Grasses1

“…Turfgrass species vary in tolerance to submergence (1, 2,3,6,7,8,9). Buffalograss 3 and bermudagrass 4 exhibit excellent tolerance to extended durations of submergence under water (4,5). The degree of injury from submersion increases with the depth of flooding (8,9).…”

“…The degree of injury from submersion increases with the depth of flooding (8,9). Grasses having at least the leaf tips extending above water level are able to survive much longer than when totally submerged (3). The type of Hooding is also a factor in the degree of kilL For example, submerged grasses are killed more readily under stagnant water than under running water (3).…”

Effect of Water Table Depth and Flooding on Yield of Millet1

“…The cool-season grass species tolerated high water tables, whereas summer-growing species were intolerant to excessive water. Several coolseason grass species survived up to 10 weeks of flooding during cool weather (2,5,9,11). Rhoades (10) found that some warm-season grass species were more tolerant to inundation than others but, as depth of flooding increased, inundation tolerance of all grasses decreased.…”

Flooding Tolerance of Annual Clovers1

“…Most forage species tolerate flooding for short time periods when in a dormant state, as demonstrated by Davis and Martin in England ( 2). McKenzie ( 4) found that sweet<;lover and alfalfa were much less tolerant of flooding during the growing season than many cool season perennial grasses.…”