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

Eni Maftu’ah1*, Muhammad Saleh1, Yiyi Sulaeman1, Khairatun Napisah1, Rusmila Agustina1, Mukhlis Mukhlis1, Khairil Anwar1, Rina Dirgahayu Ningsih1, Masganti Masganti1, Puspita Harum Maharani1, Syaiful Asikin1, Vicca Karolinoerita2, Nur Wakhid3, Afiah Hayati4, and Yuli Lestari5
 
Soil ameliorants play a crucial role in enhancing soil fertility and rice (Oryza sativa L.) production in acid-sulfate 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+0% 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 Si-humate 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.
Keywords: Iron toxicity, Oryza sativa, pyrite oxidation, risk husk biochar, soil acidity.
1National Research and Innovation Agency Republic of Indonesia, Research Center for Food Crops, Jl. Raya Jakarta-Bogor km 46, Cibinong, Bogor 16911, West Java, Indonesia.
2National Research and Innovation Agency Republic of Indonesia, Research Center for Geospatial, Jl. Raya Jakarta-Bogor km 46, Cibinong, Bogor 16911, West Java, Indonesia.
3National Research and Innovation Agency Republic of Indonesia, Research Center for Ecology and Ethnobiology, Jl. Raya Jakarta-Bogor km 46, Cibinong, Bogor 16911, West Java, Indonesia.
4Lambung Mangkurat University, Agriculture Faculty, Banjarbaru, South Kalimantan, Indonesia.
5Indonesia Swampland Agriculture Standardization Institute, Jl. Karet, Loktabat Utara, Banjarbaru, South Kalimantan, Indonesia.
*Corresponding author (enim002@brin.go.id).