Technical-grade chemical-assisted extraction of humic substances from wet decanter solids for soil amelioration in short-term incubation test

The development of smart and sustainable agriculture requires low-cost soil amendment technologies derived from agro-industrial residues. This study evaluated the use of technical-grade extractants, caustic soda (NaOH), monosodium glutamate (MSG), and urea for extracting humic substances (HS) from wet decanter solids (WDS) and assessed their potential as soil ameliorants for Ultisols. A completely randomized design (CRD) with three extractant concentrations (0.1, 0.5, and 1.0 M) and three replications was applied during a 24 h extraction period. Among the treatments, 1.0 M NaOH produced the highest HS yield (2.29%) and C-HS content (1.28%), along with a high cation exchange capacity (CEC) [172.40 cmol(+) kg-1] and an alkaline pH (12.27), indicating abundant phenolic and carboxylic functional groups as well as enriched nutrient content. Application of NaOH-extracted HS at 8,000 mg L-1 significantly improved the chemical properties of Ultisols, including increases in soil pH (+4.07), electrical conductivity (EC, +1.31 dS m-1), organic matter (OM, +9.80%), CEC [+20.6 cmol(+) kg-1], and nutrient availability (+4.42% C, +0.27% N, +34.50 ppm, and +0.41 cmol(+) kg-1 exchangeable K) compared with the control. These findings indicate that HS extracted with technical-grade 1M NaOH from WDS is an economical and easy-to-develop organic additive that supports waste utilization, improves soil function at concentration levels of 6000-8000 mg L-1 (can increase pH and P availability), and promotes sustainable agriculture based on circular bioeconomy.

Text 127316.pdf - Published Version Available under License Creative Commons Attribution. Download (1MB) Official URL or Download Paper: https://iieta.org/journals/ijdne/paper/10.18280/ij...

Actions (login required)

View Item