Why are controlled-release fertilizers advantageous for environmental health?

Controlled-release fertilizers are advantageous for environmental health primarily because they reduce nutrient leaching. When fertilizers are applied to the soil, there is a risk that nutrients can be washed away, especially in areas with heavy rainfall or irrigation. This leaching can lead to nutrient pollution in groundwater and surface waters, causing issues such as algal blooms, which deplete oxygen in water bodies and harm aquatic ecosystems.

Controlled-release fertilizers are designed to release their nutrients slowly over time, matching the plants' nutrient uptake rates more closely. This means that the nutrients remain in the soil for longer periods, reducing the likelihood of them being leached away by water movement. Consequently, the risk of nutrient runoff into nearby waterways decreases, contributing to better water quality and promoting a healthier environment.

While other factors like biodegradability, cost, and growth promotion are relevant in evaluating fertilizers, the key environmental benefit of controlled-release fertilizers lies in their ability to mitigate nutrient loss through leaching.