Sun Q, Liu J, Huo L, Li YC, Li X, Xia L, et al. Humic acids derived from Leonardite to improve enzymatic activities and bioavailability of nutrients in a calcareous soil. Int J Agric & Biol Eng [Internet]. 2020 Jun. 8 [cited 2025 Dec. 26];13(3):200-5. Available from: https://ijabe.migration.pkpps03.publicknowledgeproject.org/index.php/ijabe/article/view/5660