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Nitrogen Management in Field Vegetables [electronic Resource] : a Guide to Efficient Fertilisation

Canada. Agriculture and Agri-Food CanadaNicolas Tremblay

出版	Agriculture and Agri-Food Canada, 2001
ISBN	06623049429780662304944
URL	http://books.google.com.hk/books?id=pGuAZwEACAAJ&hl=&source=gbs_api

註釋Crops require nitrogen in much greater quantity than most other nutrients, so cropping practices often call for large applications of nitrogen fertilizer to maximize yields. Both over- and under-fertilizing with nitrogen have their costs, making efficient fertilization a priority for farmers. This guide has been designed for the farmer & agricultural professional as a handbook of information on the nitrogen fertilization of field vegetables. It begins by describing the nitrogen cycle, including inputs (soil mineral nitrogen, mineralization of organic matter, precipitation, irrigation, fertilization) and outputs (plant needs & mineral nitrogen not absorbed by the plant). It then describes methods of estimating the nitrogen fertilizer requirements of vegetable crops, including those based on experience & observation, calculation-based methods, and methods based on soil & plant analyses. Section 4 explains the use of the nitrogen balance when fertilizing and how to calculate nitrogen balance. Section 5 discusses the prevention of nitrogen leaching through improved fertilizer management & other techniques. The final section reviews factors influencing nitrate content in the edible parts of vegetables and how to control that content. Appendices include procedures for nitrate extraction & quantification using a reflectometer.