A study of the yields of various species of pasture plants, and some of their strains, when growing in a soil brought to various levels of hydrogen-ion concentration : thesis submitted for M. Agr. Sc. degree / by "548" [A.J. McNeur]

During the past few decades, our country, along with other important primary producers, has come to realise with increasing force the real importance of pasture production to mankind. In New Zealand over nine tenths of the value of our exports comes directly or indirectly from grasslands. This realisation has been reflected in the marked extension in research, not only towards the improvement of pasture species and strains, but also in an attempt to learn more of the conditions in the soil that are most ideal for maximum production. As a plant can produce only as much as its inherent potential and its external environment will allow, it becomes all workers to consider both sides of the question of maximum production. As a result of work done by the Grasslands Division of the Plant Research Bureau since its inception, strains of new pasture species have been developed which will produce very highly under conditions favourable to their growth. Thus if these strains are used in agriculture and maximum production is not obtained, managemental and environmental factors must be the limiting ones. Of the environmental factors, five claim pride of place where pasture production is concerned:- (a) Soil moisture (b) Soil and air temperature (c) Light intensity (d) Soil fertility (e) Soil acidity. In practice the first three factors are mainly dependent on climatic conditions, though by suitably controlled irrigation and drainage both soil moisture and soil temperature can be influenced and plant growth markedly increased. [From Introduction