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 West
Asia and North Africa
In West Asia and North Africa, soil
nutrients are present in insufficient amounts and crop
fertilization is out of balance. In dry-lands the limited
amount of available soil water is insufficiently utilized
due to poor root development of crops. The crop rooting
for better water use efficiency is very much affected
by soil phosphorus availability. This was demonstrated
in field research activities on efficient use of phosphate
fertilizers to increase crop production in North Africa
and West Asia. Field studies of water and P fertilizer
interactions recognized the fact that next to rainfall,
low soil fertility may be one of the most limiting factors
in this environment. The main activities undertaken
within the region are as follows:
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Diagnostic technique and phosphate fertilization strategies for the mediterranean region countries
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Efficient use of p fertilizers for increased crop production in the west asia north africa region
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Improving phosphorus soil test calibration in calcareous soils
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Regional workshop on: "accomplishment and future challenges in dry land soil fertility research in the mediterranean area", aleppo (syria), 19-23 november 1995
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Fertilisation phosphatée de la luzerne conduite en irrigué dans le haouz
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Diagnostic Technique and Phosphate Fertilization
Strategies for the Mediterranean Region Countries
Phosphorus is one of the most limiting
nutrients to crop production in the region. It is helpful
to develop techniques that enable farmers to make proper
use of phosphorus to meet the demand of the plant-soil
system, thereby increasing productivity and economic
return.
IMPHOS in collaboration with National
Agricultural Research Systems (NARSs) of the region
(Spain, France, Turkey, Jordan, Syria, Egypt, Tunisia,
Algeria, Morocco) set out to conduct a survey of phosphorus
fertilization practices at farm level (>1100 samples)
and a series of pot trials (>500 amples) under greenhouse
on soil samples.
Data processing obeyed to an approach that proceeds
in two steps:
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Diagnosis
of soil P availability is based on crop P requirement,
field past P fertilization, crop residue management
and soil P content. These combined weighed parameters
give a scale of soil P availability, being either
low, medium or high, and suggest one of three P
fertilization strategies: intensive, maintenance,
or withholding strategy. |
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For a given
fertilization strategy and crop requirement level,
a multiplier coefficient K (0 to 2.5) of P crop
removal (E) is suggested for calculating fertilizer
recommendation (F) as equals to k * E.
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The approach will help extension agent's
design appropriate and efficient phosphate fertilization
strategies for farmers. Indeed, the survey showed that
some farmers are using less fertilizer than needed for
optimal yield while others are using more fertilizer
than crop requires. The extra P added could be more
effectively used in other farm fields where P is deficient
and needed.
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