Goedert, W. J., Syers, J. K., & Corey, R. B. (2014). Potassium quantity-intensity relationships of soils from Rio Grande do Sul. Pesquisa Agropecuaria Brasileira, 10(11), 31–35. https://doi.org/10.1590/S1678-3921.pab1975.v10.17105