MSc

The present study was conducted in the main campus of Kerala Agricultural
University, Vellanikkara with the objective of preparation of a detailed soil resource
inventory. The total area of the campus is 384.56 ha. The inventory under this report was
carried out covering the eastern part of the campus comprising an area of 214 ha which is
divided into 25 blocks. The study mainly concentrated on the resource potential of the
campus with respect to soil resource. Here an attempt has been made to evaluate the
physical, chemical and electrochemical properties of the soil. One hundred and ninety
eight samples each from surface(O - 20 cm) and sub surface(20 -40 cm) layers collected
at a grid size of 80 m2 were analysed for the above properties.
Soil samples collected from different parts of the campus were predominantly
gravelly in nature both in the case of surface and subsurface samples. In the textural
analysis majority of the phases were coming under clay loam. Irrespective of depth, in
majority of the phases, surface and subsurface samples were coming under same textural
classes.
In general almost all the soils were acidic in nature. This shall be due to the high
rainfall and subsequent leaching. Electrical conductivity of the soil samples was found to
be very low both in the case of surface and subsurface soils. Buffer pH was estimated to
find out the lime requirement of the soils. It was found that buffer pH varied widely
among the samples and so also the lime requirement.
An increase in organic carbon content with depth was observed in a few phases.
Almost 91 % of the surface and 90% of the sub surface samples analysed were medium in
fertility, 7 per cent each of the surface and sub surface samples were coming under high
fertility class and the remaining 2 and 3 per cent were low in organic carbon status.
Available phosphorus content recorded low values in almost all the samples both in the
case of surface and subsurface soils. 78% of surface and 84 %of sub surface samples
were rated as low in fertility while 17 and 13 % were medium in fertility and only 5 and3
per cent of the samples from surface and sub surface were high in fertility. The results

revealed that about 63 to 65 % of soils were coming under medium fertility with respect
to available potassium.
A vailable calcium and available magnesium content showed a wide variation
depending on the degree of leaching.
Available micronutrients namely manganese, ZInC, copper, and iron were
extracted using O.IM HCI and contents was in the order as Mn > Fe > Cu > Zn both in
the case of surface and subsurface soil layers. Of these Mn, Fe and Cu in almost 98% of
the samples showed values far above the critical ranges reported where as available zinc
content was below critical range in 80 to 90 % of the samples. Only 8 to 14 % were
coming within the critical range.
P fixing capacity of the soil was estimated and it was observed that all the soils of
the study area were high in P fixing capacity. This is due to the high content of oxides of
iron and aluminium under acidic 1: 1 mineral dominated soil environment.
All the exchangeable ions present in the soil viz. calcium, magnesium, sodium,
potassium, iron, manganese and aluminium were determined using O.IM BaCl2 and
found that calcium formed the predominant cation both in the case of surface and
subsurface soils. The exchangeable ions were in the order Ca > Na > Mn > K > Mg > Al
>Fe. CEC of the soil ranged widely both in the case of surface and subsurface soils from
about 1.5 to 8 cmol (P+) kg•l.
Sodium saturation was observed very high in the case of both surface and
subsurface soils; in many cases exceeding 15 % and yet not showing any sodicity due to
low CEC and pH. Percentage base saturation of the soil varied widely from about 36 to
96 % and it was found that major part was contributed by exchangeable calcium.

The Eastern part of the campus poses several limitations for crop production in
terms of high graveliness, low CEC, high aluminium saturation, acidity, high P-fixing
capacity, low K reserves, potential influences of Na in the exchange complex, ustic
moisture regime and sloppy terrain.