Effect of Lime and Phosphorus Application on Quantity and Intensity Parameters of Aluminium and Its Uptake by Rice in Acid Saline Soils

A study was conducted to investigate the effect of lime and phosphorus application on extractable Al and aluminium potential (pH -½ pAl_M) in three highly acidic soils viz. Kari, Kayal and Karappadom soils of Kuttanad, Kerala. Even though there was an initial decline in the KCl-exctractable Al content in soil due to flooding, it gradually went up in non-limed soils. Liming at 1 LR level maintained the KCl-extractable Al at minimum level up to 60 DAT after which only liming at 2 LR level could maintain such low levels of extractable AI. Application of P did not affect the extractable Al content of soil significantly. The aluminium potential (pH-½ pAl_M) worked out at two stages clearly supported the trend obtained for the quantity parameter (i.e extractable AI), thus serving as a useful intensity parameter for the latter. Application of P as well as lime considerably reduced the AI content of plants in Kari soil whereas liming alone was responsible for the same in Kayal and Karappadom soils.