Since nitrogen (N) mineralization from soil organic matter is governed by basic soil properties (soil organic matter content, pH, soil texture, …) that are known to exhibit strong in-field spatial variability, N mineralization is also expected to exhibit significant spatial variability at field scale. An ideal and efficient N recommendation for precision fertilization should therefore account for potential soil mineralizable N considering this spatial variability. Therefore, this study aimed at estimating the management zone (MZ) specific soil N mineralization rate (SNMR) of unamended soils. A total of 76 soil samples were collected from previously delineated 21 MZs distributed across 5 arable fields in Flanders, Belgium. An aerobic laboratory incubation was conducted under controlled conditions (bulk density of 1.4 g cm-3, moisture content at 50 % water-filled pore space, and average temperature of 22.2 ºC) for a period of two months with seven sampling events. N mineralization was assessed as the net increase in soil mineral N ( + ), as a function of time. Results indicated a considerable in-field variation in soil texture with the ranges of sand (4.70–58.30 %), silt (27.90–83.40 %) and clay content (9.06–20.50 %), and total soil mineralized N (9.12–41.93 mg kg-1 soil) across the fields. The highest and lowest net SNMR was calculated as 0.50 and 0.0004 mg kg-1 soil day-1, respectively. Among MZ differences in SNMRs were significant in three fields, while remaining MZs in remaining two fields showed insignificant differences at 90 % confidence interval. In turn, total 3 of 34 MZ-pairs differed significantly (padj.: 0.023 – 0.092) from one each other. The significant differences were observed in MZ pairs having high variation in particle sizes. The SNMRs frequently showed positive correlation with pH (0.20–1.00), total N (0.12–0.99), soil mineral N (0.11–1.00) and sand (0.34–0.99), whereas negative correlations were observed for silt (-0.99 to -0.17) and clay (-1.00 to -0.11) content. In conclusion, though not many MZ showed statistically significant differences in SNMR per field despite mathematical differences, still MZ-specific SNMR determination seems to be a way to forward optimizing the existing N recommendation by incorporating SNMR in the management decision. Along with other management actions, the MZ-specific SNMR determination should facilitate designing an efficient and environment friendly precision fertilization scheme.
