ADVANCES IN GRASSLAND TECHNOLOGY OVER THE PAST FIFTY YEARS

Resumen

Advances have occurred at a remarkable rate and are interwoven below under the headings of Agronomy, Grazing and Forage Conservation. The introduction of royalties was a major stimulus to a flow of improved forage varieties by breeders. Varietal testing was formalized and resultant recommended lists are the norm in many countries. Seed is of assured genetic and analytical quality. An impressive array of herbicides and pesticides has been developed for control of weeds and pests in establishing and established swards. Nutritive valué (NV) profiling identified of the most suitable species and varieties for grazing and conservation. Analytically the development of near infra-red spectroscopy has been a notable development. On account of their high NV and N-fixing ability, forage legumes are arousing increased reappraisal and interest in their use. Fertilizer technology has led to more concentrated forms, bulk handling and a better understanding of the interactions of N, P, K and S under different managements. Organic manures are now used more rationally and farm nutrient balances are making an increasing impact in efficiency of fertilizer use. Early debate on grazing centred on methods but experimentation showed stocking rate was the key influence on animal output per unit área or per animal. Another key advance was the integration of grazing and conservation, manipulating their áreas to achieve a succesion of Ieafy regrowths of high NV; buffer feeding was also introduced as an insurance. Physiologists elucidated the role of the carbón balance in swards and of tiller growth, leading to grazing management based on sward height. The use of indigestible markers to measure faecal output and henee estímate intake was a major step forward. Silage making has become the most important method of conservation, aided by improved mechanization in all aspeets of handling, an understanding of the microbiology and biochemistry involved and notable introductions such as precisión chopping, plástic sheeting, wrapped big bales, choice of additives and improved methods of prediction of NV for ration formulation. Some of the advances are also applicable to hay making. It is forecast that the rate and degree of progress in technology, including biotechnology, will in al likelihood match or surpass the advances achieved in the past half century