The importance of red claver (Trifolium pratense) as a forage crop; growing concern about both seed and hay yields; the failure of almost continuous research on varieties, seed setting etc. to greatly improve the situation in Quebec, and preliminary surveys indicating a very high percentage of two year old plants infested by the clover root borer (Hylastinus obscurus (Marshem)), gave rise to these investigations. It has been generously supported by a grant-in-aid for the purpose, from the Quebec Agricultural Research Council to Dr. Frank Morrison.

The work presented in this thesis arose as one of the problems associated with the Canadian Forage Seeds Project (C.F.S.P.). This organization was founded in 1952 with the aim of ensuring a supply of basic seed stocks of improved varieties of forage crops. The American counterpart to the C.F.S.P. has enjoyed spectacular success, and certified seed of improved varieties forms a considerable part of total seed production. [...]

Investigation in 1953 (M.Sc. thesis) showed that fertilization with 76 pounds of nitrogen and 72 pounds of phosphate per acre, in addition to a maintenance application of 600 pounds of a 4-12-6 fertilizer, increased the nitrogen and phosphorus percentages in the corn leaf at the flowering stage. The levels of these leaf constituents and the yields at harvest were closely correlated, confirming the idea that chemical analysis of the plant at this stage of growth was a useful diagnostic tool. It was also shown that nitrogen, rather than phosphorus, was a major factor in modifying these plant characteristics.

Today Canada's pasture and range land is estimated at some sixty million acres. The most extensive acreage is found as native grass range land in the prairie provinces. In Eastern Canada there are fourteen millions of acres of pasture land which were formerly wooded and then cleared.

Red clover, recognized as the corner stone of agriculture, is one of the most widely distributed of all cultivated clovers. The production of red clover and other forage crop seed in Canada today is a very important business and various organizations are interested in the different phases which allow the farmers to obtain good material for seeding. Among those organizations the Canadian Forage Seeds Project must be mentioned.

Within the last decade the use of anhydrous ammonia as a source of nitrogen for plants has gained considerable popularity in the United States of America. Several workers have investigated crop response to gaseous ammonia in comparative studies between the gas and solid nitrogenous fertilizers. Field and laboratory studies involving the capacity of the soil to retain ammonia-nitrogen applied as a gas or in solution have also been conducted. Still other workers have investigated the effects of varying concentrations of ammonia-nitrogen upon soil microorganisms and the nitrifying capacity of soils.

One of the major phenotypic variables in red clover has been observed to be the habit of vegetative growth in the year of seeding. Bird (1948) has identified five growth types in the variety Dollard. As a result, there was initiated a continuing series of research projects in the Department of Agronomy of Macdonald College which has attempted to relate this variation to differences in management (Steppler and Raymond 1954); differences in source of seed (Lachance 1956); level of endogenous auxin in plants (Cumming 1956) and to difference in a variety of environmental conditions (Bristow 1957). [...]

Considerable interest has developed in birdsfoot trefoil as a forage legume in certain areas of North America. The greatest attention has centered on broadleaf birdsfoot trefoil (Lotus corniculatus L.) although other related species including big or marsh trefoil (L. uliginosus Schkuhr) and narrowleaf trefoil (L. tenuis Wald. et Kit.) have special qualities that make them of interest under some conditions. [...]

In the past, little attention has been given to the root systems of agricultural plants in general, and of cereal grains in particular, compared to that given to above-ground parts. Roots, however, are basic to plant life. Their importance as storage organs for food reserves manufactured in the plant, as transporters of food nutrients from the soil to above-ground organs, and for anchorage of plants in the growing medium, is well known. [...]

Competition in plant communities is one of these concepts that has been investigated and discussed extensively and yet very few people if any have a thorough understanding of all its intricacies and complexities. Any study that did or will reveal some of the unknowns of this phenomenon in grassland will be a step in the direction that will ultimately permit the attainment of the ideal pasture plant community. However, presently, until more is known, especially on the value of competition as it occurs in hay end pasture swards, any attempt to come forth with recommendations on the compounding of forage mixtures may be rather vain, because these will be only temporary.