Many agricultural crops worldwide, especially in semi-arid climates, suffer from iron deficiencies. Among plants sensitive to iron deficiency are apples, avocado, bananas, barley, beans, citrus, cotton, grapes, peanuts, pecans, potatoes, sorghum, soybeans, and numerous ornamental plants. Deficiencies are usually recognized by chlorotic, in new leaves and are typically found among sensitive crops grown in calcareous or yellowed, interveinal areas soils which cover over 30% of the earth's land surface. Iron deficiency may lead, in extreme cases, to complete crop failure. In intensive agriculture on calcareous soils, iron often becomes a major limiting nutrient for optimal crop production, thus, correction of iron deficiency is required. Various chemicals and practices are available. They are, however, costly and do not always result in a complete remedy of the deficiency. Crucial questions relative to the cost-benefit equation such as the recovery rate of plants and the long-term fertilizing effect have not yet been resolved. The complexity of iron nutrition problems requires an understanding of the chemistry of iron oxides in soils, of the chemistry of both natural and synthetic chelates, of rhizosphere microbiology and biochemistry, and of the physiological involvement of the plant in iron uptake and transport.

Many agricultural crops worldwide, especially in semi-arid climates, suffer from iron deficiencies. Among plants sensitive to iron deficiency are apples, avocado, bananas, barley, beans, citrus, cotton, grapes, peanuts, pecans, potatoes, sorghum, soybeans, and numerous ornamental plants. Deficiencies are usually recognized by chlorotic, in new leaves and are typically found among sensitive crops grown in calcareous or yellowed, interveinal areas soils which cover over 30% of the earth's land surface. Iron deficiency may lead, in extreme cases, to complete crop failure. In intensive agriculture on calcareous soils, iron often becomes a major limiting nutrient for optimal crop production, thus, correction of iron deficiency is required. Various chemicals and practices are available. They are, however, costly and do not always result in a complete remedy of the deficiency. Crucial questions relative to the cost-benefit equation such as the recovery rate of plants and the long-term fertilizing effect have not yet been resolved. The complexity of iron nutrition problems requires an understanding of the chemistry of iron oxides in soils, of the chemistry of both natural and synthetic chelates, of rhizosphere microbiology and biochemistry, and of the physiological involvement of the plant in iron uptake and transport.

This volume comprises the proceedings of the First International Rehovot Conference on Modem Agriculture and the Environment, held at the Rehovot Campus of the Faculty of Agriculture, the Hebrew University of Jerusalem, Israel, 2-6 October 1994. The conference, first in a series intended to be convened in Rehovot at 4-5 year intervals to address various aspects of the interaction of agriculture and the environment, was initiated, organised and carried out under the auspices of the Faculty of Agriculture, the leading academic institution in agricultural and environmental studies in Israel. It featured four keynote addresses, 39 invited lectures, 40 submitted papers, and 62 posters. Of these, 51 articles, written by 122 contributing authors from 14 countries, were selected by the editors to be presented in this book. All through the twentieth century, and especially ever since the advent of the Green Revolution, modem agriCUlture has been striving to feed and clothe the ever increasing multitudes of the human species through improved technology, relying heavily on tremendous inputs of fertilisers, pesticides, and various other agrochemicals. Undoubtedly, this has been a great blessing to mankind, and enormous strides have indeed been made in the never-ending struggle against starvation, but these have been achieved at a very steep price of increased environmental deterioration. In fact, modem agriculture has become one of the major factors contributing to the degradation of the world's fragile biosphere.