Release Pattern of Dissolved Silicon and Its Budgeting under Rice Planted and Unplanted Condition in Acidic, Neutral and Alkaline Soils

Abstract

ABSTRACT Release of silicon (Si) from different Si sources and Si budgeting in varied types of soils are required for the exploration of sustainable rice production. Si products are shown to be effective in improving crop growth and yield; however, its reactivity differs based on the soil type. A pot experiment was conducted by using three Si sources (calcium silicate (CaSiO3), diatomaceous earth (DE), and rice husk biochar (RHB)) in acidic, neutral, and alkaline soils under rice planted and unplanted conditions for a single season. A large variation in Si uptake by rice existed amongst the different sources of Si and was found to be higher in neutral soil followed by acidic and alkaline soil. Application of calcium silicate followed by diatomaceous earth recorded higher Si uptake in acidic (547.17 ± 39.15 mg pot−1) and neutral (632.65 ± 112.21 mg pot−1) soil whereas, rice husk biochar in alkaline soil (35.32 ± 4.60 mg pot−1). Application of calcium silicate and RHB significantly increased the plant available Si in post experimental soil. The soil solution pH of acidic, neutral and alkaline soils ranged from 5.62– 8.59, 6.62– 9.13, and 7.64– 9.37, respectively, with the application of different rates and sources of Si during the experimental period. The application of CaSiO3 followed by RHB increased the dissolved Si in acidic and neutral soil whereas RHB and DE in alkaline soil. The amount of DSi with the application of different sources and levels of Si ranged from 47– 447, 139– 751, and 161– 374 µmol L−1 in acidic, neutral, and alkaline soil, respectively. About 16 to 28% of Si in acidic and neutral soil and 10 to 19% Si in alkaline soil was accounted by irrigation water.