Improving the Physical Properties of Ex-Coal Mining Soil Planted with Sweet Corn (Zea mays saccharata L.) Using Pine Wood and Sawdust Biochar

Biochar is a by-product produced from the combustion process without oxygen at high temperatures (100-800oC) for approximately one hour. The advantage of this biochar is that apart from having several distinctive properties such as being more efficient, cost-effective, and easy to obtain, it can also improve the soil physical properties and remove toxic contaminants in ex-coal mining soil. Through its large surface area, large pore size distribution, particle types and low density, biochar can influence soil porosity, soil consistency, improve soil aggregate stability values and increase water availability for plants by up to 130%. The research was carried out at the experimental site of the Agriculture Faculty, Universitas Syiah Kuala using planting media from ex-coal mining soil. This research used a factorial randomized block design with three replications. The first factor was the biochar feedstock consisted of pine wood and sawdust. The second factor was the biochar dosage consisted of 0, 10, and 20 tons ha-1. The physical soil characteristic parameters observed were soil porosity, bulk density, and aggregate stability. The biochar characteristic parameters observed were biochar combustion results, biochar morphology, water holding capacity, and biochar bulk density. Pine wood and sawdust biochar can improve soil physical properties, especially soil porosity, but did not affect soil bulk density and soil aggregate stability. Biochar dosages of 10 and 20 t ha-1 can improve soil porosity. However, to minimize costs, the biochar application at a dose of 10 t ha-1 can be recommended.