Soil Is Not Static: Where Does Nitrogen Go?

With fertiliser prices rising sharply, every kilogram of nitrogen has real value. Yet in many cases, the question is no longer how much we apply, but how much remains available to the crop. Understanding the movement of soil and water has become a direct economic factor.

A portion of applied nitrogen never reaches the plant.

Most farming decisions are still built around application. How much should we apply, when, and in what form? Should we apply more to higher-performing zones, or less? These are important questions—but one critical factor is often overlooked: what happens after application?

Applied nutrients ≠ available nutrients.

Soil is neither uniform nor static. Micro-topography, slope conditions, soil structure, and moisture distribution together determine how water moves—and with it, nitrogen.

After a 20–30 mm rainfall event, a significant portion of applied nitrogen can shift away from the root zone. On sloped fields, especially along field edges or drainage areas, losses can reach 20–40%, while lower areas may experience accumulation.

Rainfall does not just irrigate—it redistributes our investments.

This creates a two-sided problem:

• higher areas → leaching and deficiency

• lower zones → accumulation and reduced efficiency

In practice, these deficiencies are often compensated with additional fertilizer applications—quickly increasing costs under current price conditions.

The root of the problem is that most decisions do not consider the fine-scale topography and water movement patterns within a field. Yet these describe real field behaviour far more accurately than averaged zone maps.

What matters is not how much we apply—but what remains in the root zone.

The DRONATION program introduces this missing decision layer into practice. Through high-resolution topographic and field condition analysis, it reveals micro-level differences within fields: where water accumulates, where runoff begins, and which areas are exposed to increased leaching risk.

The system does more than measure—it interprets. By combining terrain models, soil conditions, and expected rainfall, it can predict the direction and magnitude of nutrient movement following application.

This enables:

• application strategies that account for rainfall-driven nitrogen movement

• predictable and manageable leaching risk

• improved real efficiency of fertiliser use

Practical applications of the DRONATION model:

• in winter cereals top-dressing, incorporating leaching risk

• in corn base fertilisation, predicting nutrient movement

N correction maps for Cereals spring application based on NDVI map

N correction map for Corn base fertilisations, by soil potential and rainfall in seasonal vegetation.

The model helps to:

• avoid over-fertilization in accumulation zones

• adjust application rates in higher areas based on leaching risk

The next level of precision farming is not more data—but better understanding.

Water movement determines the fate of nitrogen, and nitrogen determines yield and return. This movement is not random—it can be modeled.