BC Walpola* and HU Shamudika
Department of Soil Science, Faculty of Agriculture, University of Ruhuna, Mapalana,
Kamburupitiya, Sri Lanka
Abstract
An incubation study was conducted to determine the effect of lime (L) as CaCO
, and phosphorus (P) as triple
super phosphate (TSP) on soil pH, available P, organic matter decomposition, inorganic nitrogen content, and
calcium (Ca) content of soil. Three rates of lime equivalent to 0, 1 000, 2 000 kg (CaCO3) ha-1
and three rates of
TSP equivalent to 0, 50 and 100 mg (P) kg -1
were applied in combination as treatments with three replicates. With
the increasing rate of lime soil pH was significantly (p< 0.001) increased. Both lime and TSP had significant effects
(p< 0.001) on P availability at three different soil test P extraction methods.2 000 kg (CaCO3) ha-1 with 100
mg (P) kg-1
gave the highest available P irrespective of extractant used. Bray and Kurtz-1 method extracted the
largest amount of P (5.63- 66.69 mg kg-1). Despite the varied ammonium nitrogen (NH4+-N) while Borax method extracted the smallest amount (3.42 – 42.42 mg kg-1) and nitrate nitrogen (NO3--N) contents, the NH4+-N content
decreased and NO3--N content increased in the all treatments when incubation progressed. With the increasing
rate of liming the decomposition of organic matter and the Ca content also increased.
Key words: Acidic soil, Extraction methods, Incubation, Lime, Phosphorus
Full Text :
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* - Corresponding Author
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