A study of the reaction of several variables of top growth of a perennial ryegrass/white clover pasture to different defoliation treatments and measurements on soil moisture status : a thesis presented at Massey Agricultural College in part fulfilment of the requirements for the degree of Master of Agricultural Science in the University of New Zealand

Indistinct printThe agricultural research worker must on occasion adopt a broad view of farming purely as the management of plants and animals to produce human food. He has the task of outlining many of the principles to be used in farming practice, to increase world food production, in order to meet the challenge of a growing world population. He needs to consider the biological efficiency of the living processes and systems involved in food production; in much the same way as a businessman or farmer must consider the business efficiency of his factory or farm operations. Food production may be increased either by bringing more land under cultivation or by intensifying agriculture on the existing areas of cultivation, thereby increasing production per acre. Watson (1958) described the problem as fundamentally one of increasing the total annual photosynthesis per unit area of crop, for it is the net product of photosynthesis which the farmer harvests. Photosynthesis requires light, moisture and nutrients, and as light is the only one of these factors which can not be readily supplied artificially, Donald and Black (1958) have suggested that the ultimate measure of agricultural efficiency could well be expressed in terms of the proportion of light energy utilised by the crops or pastures. The size and activity of the photosynthetic system then becomes one of the determinants of crop yield. The potential rate of photosynthetic activity is controlled by the genetic make-up of the plant. The same is true to a certain degree of the size of the photosynthetic system, but the farmer too, through various cultural and management methods, exerts considerable control over the size of the system. [FROM INTRODUCTION