Mineral Fertilizer Use and the Environment International Fertilizer Industry Association United Nations Environment Programme

9.7. Site specific fertilizer
application
The need for rational and sustainable land use,
especially in regions subject to severe population
pressures, emphasizes the need for effective land
use planning. The classification of land types
according to their agricultural suitability, together
with the implementation of soil conservation
measures, was used with great success to combat
the erosion and desertification problems
encountered in US agriculture in the 1930s.
Fertilizer recommendations should take into
consideration specific agro-climatic and
environmental conditions. General
recommendations need to be adjusted to the
conditions of the particular field. They depend on
factors such as soil characteristics, cultivation
practices, quality and quantity of irrigation water,
ground water table, crop rotations and the
managerial capacity of the farmer. The expected
yield level of a crop is an important
consideration.
The rapid progress in information technology
during the past decade, including Geographic
Information Systems (GIS) and computerized
mapping, offers the possibility of agro-ecological
zoning which can help in a preliminary selection
of crops and technologies, including appropriate
fertilizer use, suited to the local conditions and
the problems encountered.
In highly developed systems, precision
farming may use satellite communication and
detailed field and crop information to improve
farm operations and nutrient efficiency by means
of the site-specific application of fertilizers. Soil
analysis and crop deficiency diagnosis to facilitate
the fine-tuning of fertilizer rates to actual crop
requirements are of fundamental importance to
precision agriculture.
Precision agriculture does not, of course,
necessarily require sophisticated machinery and
satellite-positioning systems. Farmers in
developing countries could well improve the
precision of their plant nutrient programmes
given soil testing facilities and sound advice.

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Mineral Fertilizer Use and the Environment