Impact of Sulphate of Potash and Partially Burned Paddy Husk on Soil pH, Electrical Conductivity and Plant Phosphorus Content in Saline Paddy Soil

Abstract

The productivity of most of the paddy growing lands in Sri Lanka declines due to soil salinity. A pot culture experiment was conducted to study the impact of sulphate of potash (SOP) and partially burned paddy husk (PBPH) on soil pH, electrical conductivity and plant phosphorus content in saline paddy soil. The experiment was of a completely randomize block design in 2 x 4 factorial arrangement. The treatments comprised of two PBPH levels (0 and 625Kg/ha) and four potassium rates (0, 18, 36 and 72 kg K2O/ ha in the form of sulphate of potash. The results revealed that the combine application decreased soil pH from 7.9 to near neutral among the treatments and ranged from 7.40 - 7.46. Combining PBPH with SOP influenced the soil electrical conductivity favourably and decreased from 7.24 dS/m to <4 dS/m. Plant phosphorus concentration increased with increase in the rate of K2O application in the form of SOP from 0 to 72 kg /ha. Combining PBPH with SOP increased the phosphorus content in plants than non-amended soil. Highest plant phosphorus content was recorded at 72 kg K2O/ ha application in both amended and non-amended soil; as 4.536 and 3.721 mg/g dry weight, respectively. The results of this study suggested that, by incorporating partially burned paddy husk with sulphate of potash, soil pH, electrical conductivity and phosphorus uptake by rice crop in saline soil can be improved.