What is one consequence of over-fertilization?

Over-fertilization can lead to increased soil acidity, which is a significant consequence of applying excessive fertilizers, particularly those high in ammonium and urea. When fertilizers are applied in higher-than-recommended amounts, the nutrients, especially nitrogen, can alter the chemical composition of the soil. The decomposition of organic matter in the soil releases acids, and the excess nutrients can lead to nutrient imbalances that further contribute to acidification.

This increased acidity can have detrimental effects on plant health and growth since many plants prefer a neutral to slightly acidic pH for optimal nutrient uptake. As soil pH decreases, it can lead to nutrient deficiencies in plants, as some essential nutrients become less available in more acidic conditions. Therefore, understanding the relationship between fertilization practices and soil pH is crucial for sustainable agriculture and effective crop management.

The other options do not accurately reflect the typical direct consequences of over-fertilization in the same way; for instance, over-fertilization usually does not lead to decreased plant growth or improved water retention, and while it may sometimes enhance yields initially, it can adversely affect long-term soil health and fertility.