Nitrogentilstand

Nitrogentilstand (Norwegian: "nitrogen status") refers to the quantity, chemical form and availability of nitrogen in a given system, commonly soils, plant tissues or aquatic environments. The concept describes both the immediate pool of mineral nitrogen (nitrate and ammonium) available for plant uptake and the broader organic and microbial nitrogen fractions that influence supply over time.

Assessment methods include soil mineral N tests, plant tissue analysis, in-field sensor readings and remote sensing indices; interpretation varies by crop, soil type and season. Nitrogentilstand is shaped by inputs (fertilizers, manure, atmospheric deposition, biological fixation), outputs (crop removal, leaching, gaseous losses), and internal transformations (mineralization, nitrification, denitrification) that are controlled by temperature, moisture, pH and organic matter content.

Knowledge of nitrogentilstand is central to agronomic management for optimizing yields and nitrogen-use efficiency while reducing environmental impacts. Poorly matched nitrogen supply can lead to yield loss or excess mineral N that contributes to nitrate leaching, eutrophication and nitrous oxide emissions. Management responses include tailored fertilizer rates and timing, split applications, use of cover crops, crop rotations, precision agriculture tools and inhibitors of nitrification or urease where appropriate.

Related concepts include the nitrogen cycle, soil mineral nitrogen, C:N ratio and plant nitrogen status. Practical targets and critical thresholds are context-dependent, and decision-support systems often combine soil tests, crop models and local agronomic expertise to guide management.