Görgy. Füleky, László. Tolner, Wahdan Anas
Abstract
The replenishment
of P in the soil solution is of considerable importance from the standpoint of
plant nutrition, for the reason that the quantity of inorganic P in the
solution phase at any time, is usually insufficient to
meet crop requirement over the whole of the growing season.
Acidification is a
natural process in the environment, however human activity often increases this
tendency. Through this study we are concerned in the phosphorous recovery from
soil solid phase that have received different levels of P-additions and of
acidification applying three different water extraction methods.
A calcareous loamy
soil, pHH2O=7.9 was incubated with 0, 80 and 320 mgPkg-1
soil for one month. Different four levels of P-acidification (pH 7.9, 7.3, 6.0
and 4.5) were adjusted by adding calculated volumes of HCl
and incubating the soil samples for further one month, then equilibrated with
different rates of phosphorus as 0, 80, 160 and 240 mgP10cm-3.
The desorbed quantity of phosphorus was determined applying EUF, HWP and multistep desorption methods.
Some part of the
added phosphorus can be recovered by all methods, depending on the dose and
time of P addition (precious or recent), on acidity of the soil and on the
method used. The desorbable phosphorus amounts are in
average 19 % of sum of P-loading at 0 mgPkg-1 level, and 31 and 64 %
at 80 and 320 mgPkg-1 levels, respectively. Phosphorus recovery is
generally more in acidified soil then in non acidified one but at high
fertilizer dose it is somewhat less.