Variables: total_organic_carbon Keywords: land use Substances: 5-Methylpyridine-3-carboxylic-acid (DJDHHXDFKSLEQY-UHFFFAOYSA-N) 4-Aminopyrin (4-Aminoantipyrin 4-AA) (RLFWWDJHLFCNIJ-UHFFFAOYSA-N) 2-4-D (OVSKIKFHRZPJSS-UHFFFAOYSA-N)