What does the N-index particularly assess concerning nitrogen applications?

The N-index is specifically designed to evaluate the risk associated with nitrogen applications, particularly focusing on the potential for nitrate leaching into groundwater and surface water. This assessment is crucial during the growing season when crops are actively taking up nutrients, and there may be higher risks of nitrogen not being sufficiently absorbed by plants.

The correct choice highlights that the N-index provides insights into how nitrogen managed improperly—such as excessive application—can lead to elevated nitrate levels in leachate during this active growth period. Understanding this risk helps farmers to implement better nitrogen management practices, ensuring that crops receive adequate nutrients while minimizing environmental impacts.

In contrast, assessments relating to timing for nutrient absorption, seasonal risks, and effects on soil pH are not the primary focus of the N-index. While timing of applications and soil pH are important factors in overall nutrient management, they do not specifically reflect the role of the N-index in assessing nitrate leaching risks, particularly in the context of the growing season.