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The submission for the Degree of Doctor of Agricultural Science is based on a series of twenty-eight papers arising from research carried out at the C.S.I.R.O., Division of (Tropical Pastures, Cunningham Laboratory, St, Lucia, Queensland, and covering a period from 1952 to 1969. The papers are divided into three groups, viz: -
1. Nutrition and mineral characterisation of the pasture species.
2. Regional investigations, 3. Techniques and miscellaneous, 1. Nutrition and mineral characterisation of the pasture species. This group comprises fourteen papers covering pages 1 to 191. The papers are based on the results from a portion of a larger programme in which the central theme is "mineral characterisation of the species". Information gained leads to (a) relative responses of the species to increasing applications of a deficient or toxic nutrient or element, (b) the effect of an applied nutrient or element on the full mineral composition of the plants (nitrogen, phosphorus, calcium, magnesium, potassium, sodium, chloride and others), (c) diagnostic criteria from the foregoing, using either critical percentages, ratios of various nutrients or toxicity threshold values, and (d) visual foliar symptoms of each particular deficiency or toxicity for each species. Initially the programme only encompassed v/hole plant tops and one stage of growth, because of the number of species and plant nutrients under investigation; however the programme allows for intensification at a later date, mailing use of plant parts of differing physiological age and nutrient element fractionation in those plant parts. The last two papers of this group deal with the basic explanation and application of diagnostic criteria to plant nutrition. 2. Regional investigations The papers in this group cover three regions. Five of them, pages 192 to 230, result from investigations into the nutrient status of the soils of the southern region of the Queensland Coastal Lowlands (Wallum), The overall programme included both species and plant nutrient testing followed by testing of animals on the pastures developed. Only those aspects concerned with the nutritional state of soils of the Beerwah area are reported here. Two of the papers, pages 231 to 242 are concerned with nitrogen and sulphur deficiencies in certain soils of the Darling Downs, Queensland, The second paper of this portion, while reporting responses on wheat, was designed to use wheat and naturalised medic Medicago denticulata as test species, but because of adverse environmental conditions, the medic component was not sampled. The remaining paper, page 243 , was concerned with a solodic soil which was used as a university student project in which I was one of the advisers, = 3. Techniques and Miscellaneous These papers were based on the development of philosophies, ideas and techniques throughout the time period occupied by the two prior groups, There are three papers on water culture and sand culture techniques, one on general techniques as applied to soil and water culture investigations within this laboratory, one on general nutrition of legumes in relation to the production of nitrogen and one on general aspects of plants needs (water, food, light and energy). Details of papers are given in the Table of Contents.
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