Vol. 17 No. 1
Acidity amelioration practices for improving primary and secondary soil nutrient availability under rice cultivation in acid sulphate (Vaikom Kari) soils of Kuttanad
Author(s): V. S. DEVI
Abstract: The experiment was conducted in farmer’s field of Vaikom Kari soils of strongly acidic nature in Kallara panchayat in Kottayam district from November 2014 to March 2015. The experiment was laid out in RBD with seven treatments in three replications with rice var. Uma (MO-16). The treatments included burnt lime shell, dolomite and rice husk ash (RHA) applied as two splitsas basal + 30 DAS or as basal + one week before third dose of fertilizer application or PI (panicle initiation) and a control without ameliorants. The ameliorated plots showed higher organic carbon status compared to control. Burnt lime shell as basal + one week before PI and dolomite treatments recorded higher soil available N at seedling stage and at tillering and PI stages, any treatment except control could register higher available N in the soil. Any liming material applied as basal + 30 DAS improved soil available P status. No significant effect of treatments on available K was observed. Burnt lime shell or dolomite treatments resulted in higher availability of Ca while dolomite treatments registered higher availability of Mg in the soil. At all stages except harvest, the control plots recorded significantly higher status of available S. Significant and positive correlation of pH with available Ca was observed at all stages of crop growth. Dolomite was found to be superior compared to burnt lime shell or rice husk ash with respect to soil pH as well as available nutrient status in ameliorating soil acidity in Vaikom Kari soil. Split application of dolomite as basal dose and at 30 DAS proved more effective than application as basal dose and one week prior to fertilizer application at panicle initiation stage.