Nuon D. Effects of leonardite and nutrient management on growth and yield of cowpea (Vigna unguiculata L. Walp.). J. Sci. Agri. Technol. [Internet]. 2022 Jun. 8 [cited 2024 May 5];3(1):25-9. Available from: https://ph02.tci-thaijo.org/index.php/JSAT/article/view/245816