What environmental concern is associated with over-irrigation?

Over-irrigation leads to waterlogging and nutrient leaching, which significantly affects the environment and agricultural productivity. When the soil becomes overly saturated with water, air pockets in the soil can be displaced, leading to waterlogged conditions. This can suffocate plant roots, inhibiting their ability to absorb oxygen and effectively leading to root rot or other detrimental effects on plant health.

Additionally, over-irrigation can cause the leaching of nutrients from the soil. As excess water moves through the soil profile, it can carry away essential nutrients such as nitrogen, phosphorus, and potassium that are critical for plant growth. This leaching not only deprives the plants of necessary nutrients but can also lead to nutrient runoff, potentially contaminating nearby water sources and contributing to issues like eutrophication in aquatic ecosystems.

In contrast, increased soil temperature, reduced plant growth, and enhanced biodiversity are not direct consequences of over-irrigation. These factors may relate to various agricultural practices or environmental conditions, but they do not specifically arise as a consequence of the practice of over-irrigation itself. Thus, the concern primarily linked to over-irrigation is indeed waterlogging and nutrient leaching.