Abstract:
Phosphorus is considered as a
basic essential element for plant growth
which cannot be substituted or manufactured
and is, therefore, a scarce resource to ensure
food security; its sound management is
considered important. One of the factors that
play a significant role in its management is
the determination of the critical available
phosphorous (P) level in soil, in order to
decide whether to apply P fertilizers or not.
Since several soil and plant factors affect the
value of the critical available soil P, it is
considered necessary to carry out special
experiments, in order to determine the soil
critical P value for an area and a specific
crop. The purpose of the present study was
to establish critical soil and plant P values
for wheat. A greenhouse pot experiment was
performed on seven representative
calcareous soils from the Thessaly plain in
central Greece. The soils were deficient in
available P and so they were fertilized with
various rates of P. At appropriate stages, the
above-ground plant parts were harvested and
analysed for basic nutrients, including P. At
the same time, soil samples were also taken
and analysed for available P. The Cate and
Nelson technique was applied, to determine
critical values of both soil and wheat tissue
P values. It was found that the critical soil P
is 11 mg P kg-1 and the critical value for
wheat tissue is 0.24% P dry matter.
