Slurry application is becoming more important given tightening environmental regulations (Nitrates Directive, Green Deal) and rising mineral fertiliser prices. Slurry is a valuable fertiliser, provided it reaches the soil and not the atmosphere.
Disc injection into the soil (e.g. Duport All Track) places slurry into slits cut into the sward, without damaging it, with minimal traction requirements and the option of working in cereals as well. It is the method with the lowest nitrogen losses: with digestate, the manufacturer states yield gains of up to +15% compared with a trailing hose. Application rate adjustable within 8–60 m³/ha.
Trailing hose application (trailing hose / Schleppschuh, e.g. Duport SLV 12048) lays slurry in bands close to the ground; “skate”-shaped shoes part the sward, so the grass stays clean. It is faster and simpler than disc injection, although with digestate it gives somewhat higher nitrogen losses than soil injection.
Splash plate application (surface spreading) is the cheapest method but has the greatest ammonia losses and, since 2025, is restricted or banned in many nitrate vulnerable zones (OSN).
A separate Duport line is the injection of liquid mineral fertilisers (RSM) using CULTAN technology: the Liquiliser applicator with the PTW tanker pump. This is not a slurry machine: it works exclusively with mineral fertilisers, injecting ammonium nitrogen into the root zone. Both techniques share one goal: nitrogen in the soil, not in the atmosphere.