What is a primary consequence of poor nutrient management in agriculture?

The primary consequence of poor nutrient management in agriculture is water pollution from runoff. When farmers apply excessive fertilizers or do not manage their nutrient inputs properly, the excess nutrients, particularly nitrogen and phosphorus, can leach into nearby water bodies. This runoff often leads to eutrophication, a process that causes algal blooms. As these blooms die and decompose, they consume oxygen in the water, leading to dead zones that are uninhabitable for aquatic life. This situation not only degrades water quality but also negatively impacts biodiversity in aquatic ecosystems.

The other options reflect positive outcomes that are generally associated with effective nutrient management. For instance, increased soil fertility and enhanced crop resilience are benefits of properly managing nutrient applications. Improved biodiversity is also often a result of sustainable agricultural practices that include thoughtful nutrient management, but these results are not the outcomes of poor management. Therefore, the correct answer emphasizes the serious environmental impact associated with inadequate nutrient management practices.