Answer:
Due to toxicity of chemicals.
Step-by-step explanation:
Carlos decided to not want try to plant in the soil having high chemical levels because high decomposition increases chemical levels to a limit which can damage the plant. If there is high level of chemicals than normal in the soil, so it can burn the roots of the plants and the plant will not be able to absorb nutrients that leads to the death of plant so the decision of Carlos is right to not grow plant in such type of soil having high chemical levels.