We investigated P retention by an Alfisol treated with lime and gypsum. For this purpose a surface sample of
Pindorian series (Udic Haplustalf) receiving either lime or gypsum @ 200 g kg·1
soil was incubated under lab
condition after adding P @ nil and 100 mg P kg·1
. Soil treatment with lime and gypsum significantly (p < 0.001)
decreased water-soluble and NaHC03 extractable (Olsen) P in descending order at different rates of P
application. On an average, reduction in NaHC03 extractable P by lime addition was 36 % (range 30 to 37 %)
which was 52 % (range 48 to 53 %) by gypsum addition. Relationship between water-soluble and soil retained
(sorbed) P was best described by the Freundlich equation. Two P sorption equations at low (5 to 25 mg P kg"
soil) and high (50 to 300 mg P kg" soil) rates of P application were observed for lime-amended soil. An
augmented tendency of P retention by solid phase was revealed by higher intercept and slope values calculated
for Freundlich equation in lime and gypsum amended soils. Further studies on P release pattern are suggested in
lime and gypsum amended soils, which would be important for plant nutrition.
Key words: P application- calcareous soils- P nutrition- Olsen P
