Si-Humate as soil ameliorant to improve the properties of acid sulfate soil, growth, and rice yield

Soil ameliorants play a crucial role in enhancing soil fertility and rice (Oryza sativa L.) production in acidsulfate soils. This research aims to study the impact of Si-humic ameliorants on soil chemical properties, plant growth, Fe levels, and rice production in acid -sulfate soil. The experiments were conducted at the Laboratory and Greenhouse of the Indonesia Swampland Agricultural Research Institute. The greenhouse experiment adopted a factorial RCBD with Factor 1 representing the ameliorant formula type: 100% lime (F0), 30% commercial humate+30% rice husk ash+40% lime (F1), 30% water hyacinth humate+30% rice husk ash+40% lime (F2), 30% water hyacinth humate+30% rice husk biochar+40% lime (F3), 30% commercial humate+30% rice husk biochar+40% lime (F4), and control without ameliorant. Factor 2 represents dosage of soil ameliorant: 0, 1, 2, and 4 t ha( -1). Observations included soil properties such as pH, exchangeable Fe, available P, plant growth, Fe toxicity, yield, and yield components. Silicon-humic soil ameliorant demonstrated the ability to enhance soil pH from 3.16 to 3.63, available P from 6.12 to 30.16 mg kg( -1), and decrease Fe 690 to 371 mg kg( -1). Specifically, the F3 Si-humate formulation alleviated Fe toxicity, enhanced P availability, promoted rice growth, and improved yield. The application of 4 t ha( -1) Sihumate F3 had the best effect in increasing grain yield by 4.22 g pot( -1 )compared to the control. The application of Si-humate F3 not only improved soil quality and increased rice yields but also reduced the need for lime, contributing to the potential maintenance of soil health.