Jordbrugsvidenskab

This book introduces basic and practical information on fertigation to researchers, extension agents and growers.  To provide understanding of the basic issues regarding the appropriate selection of fertilizer injectors, fertilizer compounds used in fertigation for growing various field and horticultural crops. The book provides useful basic principles and practical information concerning fertilizer management and fertigation techniques of field, horticulture, and medicinal and aromatic crops. The book focuses on the agronomic value of fertigation practice and provides the reader with best practical advice required for successful fertigation based on the field experience. This book summarizes the basic principles and practices of fertigation techniques to ensure accurate and efficient crop nutrition. The book consists of 5 chapters covering the following topics: Introduction to chemigation and fertigation, selecting an injector for fertilizer/chemical injection, fertilizers for fertigation, major, secondary, and micronutrient fertilizers used in fertigation, and fertigation practices: Egyptian case study. It also includes appendixes for fertigation calculation examples, calibration of an injection pump, calculating the quantities of fertilizers needed for fertigation,  nutrients requirements per each ton of crop yield produced, macronutrient requirements for some filed, fiber, fruit, vegetable crops, and medicinal and aromatic plants.Fertigation is one of the smart practices that help attains sustainable food production and minimize environmental pollution. Fertigation is the application of dissolved mineral fertilizers, soil amendments, and other water-soluble products to the roots of crops through irrigation water. This book provides understanding of the basic issues regarding the appropriate selection of injectors and fertilizer compounds used in fertigation for growing various field and horticultural crops which are essential to attain higher productivity, increasing food security and reducing food contaminations. It also clarifies the advantages of fertigation and set solutions to overcome its disadvantages.

Environmental Chemistry is a relatively young science. Interest in this subject, however, is growing very rapidly and, although no agreement has been reached as yet about the exact content and limits of this interdisciplinary discipline, there appears to be increasing interest in seeing environmental topics which are based on chemistry embodied in this subject. One of the first objectives of Environ mental Chemistry must be the study of the environment and of natural chemical processes which occur in the environment. A major purpose of this series on Environmental Chemistry, therefore, is to present a reasonably uniform view of various aspects of the chemistry of the environment and chemical reactions occurring in the environment. The industrial activities of man have given a new dimension to Environ mental Chemistry. We have now synthesized and described over five million chemical compounds and chemical industry produces about hundred and fifty million tons of synthetic chemicals annually. We ship billions of tons of oil per year and through mining operations and other geophysical modifications, large quantities of inorganic and organic materials are released from their natural deposits. Cities and metropolitan areas of up to 15 million inhabitants produce large quantities of waste in relatively small and confined areas. Much of the chemical products and waste products of modern society are released into the environment either during production, storage, transport, use or ultimate disposal. These released materials participate in natural cycles and reactions and frequently lead to interference and disturbance of natural systems.

Today, at the beginning of the third millenium, just three cereal grains - wheat, rice and maize - dominate the world's food supply, accounting for some 75 % of all grains produced. This food "e;oligoculture"e; poses some risks for the future of humankind. The risk of catastrophic food crop failure through insect pests or fungal diseases is ever greater as genetic diversity is reduced. The introduction of genetically modified cereals may exacerbate this situation, as different speeies will share the same genes conferring resistance to pests. The intensive cultivation practices needed to produce the required high yields of these highly developed cereals, the so-called Green Revolution, is leading to environmental degradation through denudation of the soil and pollution of the environment due to pestieide and fertilizer runoff. In addition, the undoubted benefits brought about for many by the Green Revolution, with its use of intensive agricultural practises, cannot be shared by all. Such cultivation practises are often inappropriate in the developing world where farmers simply do not have the income to purchase the required agricultural machinery, inorganic fertilizers and pestieides. Also, the environmental con- ditions in much of the developing world, characterised by frequent droughts interspersed with short periods of very high rainfall, are espeeially dam- aging to the large areas of unprotected soil which result from mechanised agriculture. Reliance on so few different grains for our nutrition also appears to be detri- mental to our long-term health.

Large areas of the warm, humid tropics in Southeast Asia, the Pacific, Latin America, the Caribbean, and Africa are hilly or mountainous. Jackson and Scherr (1995) estimate that these tropical hillside areas are inhabited by 500 million people, or one-tenth of the current world population, many of whom practice subsistence agriculture. The region most affected is Asia which has the lowest area of arable land per capita. Aside from limited areas of irrigated terraces, most of the sloping land, which constitutes 60% to 90% of the land resources in many Southeast Asian countries, has been by-passed in the economic development of the region (Maglinao and Hashim, 1993). Poverty in these areas is often high, in contrast to the relative wealth of irri- gated rice farms in lowland areas that benefited from the green revolution. Rapid population growth in some countries is also exacerbating the problems of hillside areas. Increasingly, people are migrating from high-potential lowland areas where land is scarce to more remote hillside areas. Such migra- tion, together with inherent high population growth, is forcing a transforma- tion in land use from subsistence to permanent agriculture on fragile slopes, and is creating a new suite of social, economic, and environmental problems (Garrity, 1993; Maglinao and Hashim, 1993).

In an era where climate change, natural catastrophes and land degradation are major issues, the conservation of soil and vegetation in mountainous or sloping regions has become an international priority. How to avoid substrate mass movementthroughlandslidesanderosionusingsustainableandecologicallysoundtechniquesisrapidlybecominga scienti?c domain where knowledge from many different ?elds is required. These proceedings bring together papers from geotechnical and civil engineers, biologists, ecologists and foresters, who discuss current problems in slope stabilityresearch,andhowtoaddressthoseproblemsusinggroundbio-andeco-engineeringtechniques.Aselection of papers were previously published in Special Editions of Plant and Soil (2005), volume 278, 1-179, and in the Journal of Geotechnical and Geological Engineering (2006), volume 24, 427-498. Ground bioengineering methods integrate civil engineering techniques with natural materials to obtain fast, effective and economic methods of protecting, restoring and maintaining the environment whereas eco-engineering has been de?ned as a long-term ecological strategy to manage a site with regard to natural or man-made hazards. Studies on slope instability, erosion, soil hydrology, mountain ecology, land use and restoration and how to mitigate theseproblemsusingvegetationarepresentedbybothscientistsandpractitioners.Papersencompassmanyaspectsof this multidisciplinary subject, including the mechanisms and modelling of root reinforcement and the development of decision support systems, areas where signi?cant advances have been made in recent years.

Saline land is a resource capable of significant production. Recent advances in research in breeding for salt tolerance in wheat, biotechnology in rice, and selection and rehabilitation of salt-tolerant plants are of economic importance in arid/saline conditions.This book gives some practical approaches for saline agriculture and afforestation, and describes examples of cultivating salt-tolerant/halophytic plants for commercial interest on salt-affected land or with highly salinized water in Australia, China, Central Asia, Egypt, Pakistan, and Russia. It also explores the possibilities of arid/saline agriculture and afforestation in UAE.