Mineral Fertilizer Use and the Environment International Fertilizer Industry Association United Nations Environment Programme
Download 213.65 Kb. Pdf ko'rish
|
2000 ifa unep use
- Bu sahifa navigatsiya:
- 1.2. Where are fertilizers used
Jacqueline Aloisi de Larderel
Director UNEP Division of Technology, Industry and Economics. Luc M. Maene Director General International Fertilizer Industry Association (IFA). 6 Mineral Fertilizer Use and the Environment Note: In this document: • Mt = million tonnes • Kt = thousand tonnes • Mha = million ha • Phosphate and potash may be expressed as their elemental forms P and K, or as their oxide forms, P 2 O 5 and K 2 O. Nitrogen is expressed as N. Mineral Fertilizer Use and the Environment 7 1. An introduction to mineral fertilizers • improve unfavourable or to maintain good soil conditions for cropping. The existence of a close relationship between fertilizer consumption levels and agricultural productivity has been established beyond doubt. Amongst the various agricultural inputs, fertilizers, perhaps next only to water, contribute the most to increasing agricultural production. In this publication, the term “mineral” fertilizer is used in preference to terms such as “chemical”, “artificial” or “synthetic” fertilizers. Apart from nitrogenous fertilizers, they are, in fact, more or less purified minerals. In the case of nitrogen, approximately 99% of the total supply is produced from ammonia, which is manufactured from the abundant atmospheric nitrogen reacted with hydrogen. 1.2. Where are fertilizers used? The use of fertilizers as a regular farming practice began in most European countries in the mid to late nineteenth century but the greatest increase in consumption in these countries occurred in the three decades following World War II. Their increasing use in the developing countries started in the 1960s. In 1960, 87% of the world fertilizer consumption was accounted for by the developed countries, including the USSR and the countries of Central Europe. From 1980 to 1990 consumption tended to stabilize in these regions, apart from the USSR, where it increased until 1988. Population growth had leveled off, almost everyone was adequately fed, world agricultural exports had stagnated due to economic problems in the importing countries and on well managed farms the economic optimum of the available varieties had been reached. Download 213.65 Kb. Do'stlaringiz bilan baham: |
Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan ©fayllar.org 2024
ma'muriyatiga murojaat qiling
ma'muriyatiga murojaat qiling