Biological Nitrogen Availability in Vineyards: Assessing the Influence of Soil Particle Size Fractions and Spatial Distribution

Abstract

Perennial Vitis vinifera rely heavily on soil-derived nitrogen (N) for sustained growth, yet accurately measuring soil N supply (SNS) remains challenging, often resulting in excessive fertilizer use and environmental impacts. Biological Nitrogen Availability (BNA) method, a in-season measure of SNS, is a new tool for assessing the impact of crop management on the environment. However, its validity in vineyard remains unverified. In addition, critical knowledge gaps persist regarding how soil particle size fractions interact with organic N pools (labile vs. stable) to influence SNS and spatial distribution across vineyard. To address these knowledge gaps, we examined soil N dynamics in 11 vineyards by implementing BNA method to estimate growing season soil N mineralization (GSN) and analyzing N content in distinct soil fractions (>53 µm, <53 µm, and soluble organic N). N in the sand-sized fraction was critical for stable N pool, while N in the micro-fraction was more closely associated with the labile N pool and exerted a stronger influence on GSN. Furthermore, the labile N pool was more sensitive to vineyard location and soil depth than the stable N pool, highlighting the importance of site-specific soil management practices. Topsoil in primary grape-growing areas of Nova Scotia could supply approximately 218 kg N·ha-1 of GSN. By quantifying vineyard SNS and elucidating its interaction with soil fraction and spatial distribution across vineyard, our study offers insights that can guide sustainable N management decisions for grape growers and policymakers, with implications for optimizing productivity while maintaining soil health and minimizing environmental impacts.

Keywords: Vineyard Soil Nitrogen Supply, nitrogen mineralization, Particle Size Fraction, Spatial Distribution