| dc.description.abstract | The hydrogen ion concentration (pH) changes in soil
can be very important in determining the yield of plants.
Linear relationships have been found between the soil- and
the plant-avai lable trace elements.
Induced ion-chlorosi s has been associated with excess
(toxic) levels of cobalt and copper in soils and consequently
in plants. "Bronz inq" disease in rice has been associated with
high iron levels while both an excess and deficiency of
molybdenum and zinc lead to stunted plant growth. Manganese
disorder leads to necrosis of young leaves and stunted root
growth. To observe the effect of pH on the availability of
these trace elements in soil, liming and acidification of both the
acidic and the basic soils respectively were done. The
available contents were then obtained after pH analyses,
extraction using O.lM HCI, complexation using both APDC
(pH 2) and NaDDTc (pH 6) and irradiating following the
EDXRF analysis technique.
Total contents of the elements 'In different soils were
obtained by pelletilization. Two binding agents (PVP and
starch) were tried out and compared for the low organicmatter
soils.
While no obvious relationships were observed between
the total and available contents of these elements, the available .,
contents changed, though not linearly with the pH variation.
Thus one can predict and pick out the pH at which a higher
or lower elemental concentration may be obtained as desired
hence a way of varying its amounts in soils and plants.
PVP was found to be a good substitute for starch while
making pellets of very dry, low organic-matter soils (eg.
sands) .
EDXRF technique was found to be a fast, precise and
accurate method of soil analysis. | en |
