Soil half-life, DT50, measures what aspect of a pesticide in soil?

The soil half-life, often denoted as DT50, measures the persistence of a pesticide in the soil. This is a critical parameter because it indicates how long a pesticide remains active and potentially harmful within the soil environment before it breaks down to half of its original concentration. Understanding persistence is essential not only for assessing the environmental impact of pesticide application but also for planning effective pest management strategies.

The other aspects mentioned, such as solubility, adsorption, and toxicity, do not directly relate to how long a pesticide stays effective or intact in the soil. Solubility refers to how well a pesticide dissolves in water, which influences its mobility and potential for runoff. Adsorption relates to how strongly a pesticide binds to soil particles, impacting its availability to pests and rate of degradation. Toxicity measures the harmful effects of the pesticide on living organisms but does not indicate how long the pesticide remains in the soil or how it degrades over time. Therefore, DT50 specifically focuses on persistence, making it the correct choice in this context.