Assessing the available silica of paddy soil on different landforms

Fertilization of paddy plants with nitrogen (N), phosphorus (P), and potassium (K) fertilizers that has been ongoing so far has not reached the expected yield potential. The limited availability of Si in paddy soil affects paddy crop productivity and nutrient uptake of N, P, and K. This research aimed to study the effect of landform position on available Si of paddy soil and the relationship of soil chemical properties to available Si. The research method used was a survey research method using a purposive sampling technique based on a unit map of paddy soil. On the lower volcanic slope, five samples of soil and irrigation water were taken. In the lacustrine basin landform, five soil and water samples were taken. Soil and water samples were then analyzed for available Si content in soil and water, soil and water pH, cation exchange capacity (CEC), electrical conductivity (EC), C-organic, carbonate content (CaCO3), redox potential. The results of the laboratory analysis were then one-way variance analysis at 5% significance level and correlation-regression analysis. The results showed that the position of the landform did not affect the available Si content. The following variables, namely soil pH (r=0.75), CEC (r = 0.71), soil EC (r = 0.75), water pH (r = 0.90), and water EC (r = 0.75) had a moderate to strong relationship with the available Si of paddy soil. Water's pH and EC value are the potential to be used as easy and practical indicators in estimating the available Si of paddy soil.