Spatial distribution of status silicon availability for plant and its effect to rice yield

Silicon (Si) is a beneficial element for rice plants. However, evaluating the Si availability status of paddy soil is rarely done. This study aimed to investigate the Si availability for plant (Si_AP), spatial distribution, Si_AP correlations with some soil properties and the effect of Si_AP status on the rice yield. This study used a survey method to collect paddy soil and water sample. The pot experiment method was used to evaluate paddy plant response to Si_AP level. Based on K-means, cluster analysis showed that soil Si_AP was categorized low (< 147 mg SiO₂ kg^-1), moderate (147 – 224 mg SiO₂ kg^-1) and high (> 224 mg SiO₂ kg^-1). The Si_AP status of the paddy soil area of 26,395 hectares (25%), 61,744 hectares (59%) and 15,952 hectares (15%) was categorized as low, moderate and high, respectively. This present study revealed that the upland area paddy soil has higher Si_AP than the lowland area. Total silicon dioxide (SiO₂) and clay percentage were negatively correlated with the SiAP in soils. Silicon addition to the paddy soil with Si_AP status showed low to high increase in rice yield by 0.2%, 3.9% and 2.7%.