Koshy, M MSheela, SKAU2020-02-112020-02-111988http://krishikosh.egranth.ac.in/handle/1/5810142865PGAn investigation of the distribution, fixation and availability of phosphorus in the surface (0-20 cm) and subsoils (20-40 cm) of 15 locations in the Kole area of Trichur district of Kerala was carried out in relation to their physico-chemical properties. The surface and subsurface layers showed significant difference in total « In all soils except In the soil from Kanjani area total phosphorus decreased markedly with depth. The subsurface layer of Kanjani contained higher amounts of total P^O^ which may be due to the accumulation of organic-R in this layer* Total Pg05 was significantly and negatively correlated with coarse sand and fine sand and significantly and positively correlated with clay, silt and organic carbon. All inorganic fractions were positively and significantly correlated with total In the case of available P2O5, the maximum accumulation was found in the surface layer except in the Kanjani area. The variation in available P was not in direct proportion to the total P content. Fractionation study showed that saloid-P was the smallest fraction in these soils. In all locations saloid-Pdecreased with depth except at Kanjani which might he due to accumulation of organic matter in the subsurface layer. Al-P was the third most abundant fraction in these soils next to Fe-P and Red-P. Fe-P fraction was the most widely distributed fraction. The predominance of Fe-P in these soils may be attributed to the low pH and high content of sesquioxides. The second most abundant fraction was the Red-P, Occluded-P and Ca-P have not contributed much to the pool of total-P. Of the six inorganic fractions studied saloid-P, Al-P, Fe-P and occluded-P showed significant differences between the two depths. The phosphorus fixing capacity of these soils ranged from 15.0 to 8Q.0 percent with averages of 61.1 and 63.4 percent respectively in the surface and subsurface soils. Correlation study indicated a significant positive correlation between P fixation and total iron, total aluminium, total sesquioxides, clay, silt and organic matter.ennullThesis