The Eighth International Colloquium for the Optimization of Plant Nutrition was held in Lisbon, Portugal, 1992, and was attended by 280 scientists from 34 countries. The programme allowed the participants ample opportunity for discussions, and exchange of results and ideas. The present volume includes 103 refereed contributions that clearly reflect the main themes of the Colloquium. The published papers are related to the following problem areas: plant analytical procedures and associated concepts; diagnosis of nutrient status of plants in relation to fertilizer application; physiological and biochemical effects of stress (nutrient deficiencies/toxicities, salinity/alkalinity); assessment of nutrient requirements by crops and improvement of nutrient use efficiency based on dynamic models; optimization of crop nutrition in integrated agriculture in terms of maximum productivity and profitability, technical feasibility, and reduction of environmental pollution. Since 1964, International Colloquia have been organized every four years under the aegis of what is now known as the International Association for the Optimization of Plant Nutrition (IAOPN).The aim of these meetings has been to assess the continuing and increasing role of plant nutrition in developments in horticulture, agriculture, and forestry. Major progress has been made in use of artificial growth media, diagnosis of plant nutrient requirements and disorders of crops, the ongoing quest to improve both yield and quality of crops through efficient use of fertilizers, and the introduction of methods and materials in crop nutrition that spare the environment.
