Which nutrient is typically overapplied when manure is applied to meet nitrogen requirements?

When manure is applied to meet nitrogen requirements, phosphorus is typically overapplied. This situation arises because many types of livestock manure, such as poultry or swine manure, tend to have high concentrations of phosphorus relative to nitrogen.

In nutrient management practices, maintaining a balance between nitrogen and phosphorus is crucial for environmental protection and crop health. Farmers often calculate the amount of manure needed based on the nitrogen requirements of their crops. However, since the phosphorus content in manure can be much higher compared to nitrogen, applying enough manure to satisfy the nitrogen needs can lead to excess phosphorus being introduced into the soil. Over time, excessive phosphorus can lead to nutrient runoff, contributing to water quality issues such as algal blooms in nearby bodies of water.

This understanding highlights the importance of not only addressing nitrogen requirements but also considering the phosphorus levels in manure applications to prevent environmental degradation.