What is a potential impact of over-irrigation?

Over-irrigation can lead to water waste and nutrient leaching, which is a significant concern in irrigation practices. When soil is saturated beyond its capacity, excess water can carry away essential nutrients, such as nitrogen and phosphorus, from the root zone of plants. This not only depletes the soil of critical nutrients needed for healthy plant growth, but it can also contaminate nearby water sources as those nutrients wash away, leading to environmental issues like water pollution and eutrophication in aquatic ecosystems.

In addition to nutrient leaching, over-irrigation contributes to inefficiencies in water usage, resulting in increased costs and potential long-term damage to soil structure. If the soil remains too wet for extended periods, it can affect root health and other soil properties, further impeding the growth of plants.

Other impacts such as improved plant growth or enhanced soil aeration would not occur as a result of over-irrigation; in fact, those outcomes are typically associated with balanced and appropriate watering techniques. Increased pest resistance is also less likely, as excessive moisture can create favorable conditions for pest development rather than resistance. Thus, the correct answer highlights the critical negative consequences of over-irrigating practices in terms of resource management and environmental health.