Slurry and farmyard manure have never been more valuable given the current prices for fertiliser.
As the slurry spreading season opens for counties in zone A and B, following some of the outlined tips can help make the best use of slurry and reduce the reliance on chemical N.
Knowing the value of fertiliser value of slurry
The nutrient value of slurry varies depending on the livestock that produced the waste, the diet these animals were fed and the dry matter content.
Slurry produced from intensively finished cattle has a higher fertiliser value than the waste produced by dry cows on a silage-only diet.
Also, watery slurry makes nutrients more readily available for plant uptake when spread in the right conditions.
Where possible, direct slurry from finishing cattle to more responsive swards in early spring and fields with lower P and K status. Dry cow slurry can be targeted to fields with higher P and K status.
This means a soil test may be required to determine the P and K status of certain fields. Complete any soil sampling before spreading slurry this spring.
Don’t be in a mad rush to spread once the closed period ends
Slurry is a valuable fertiliser, so do not waste it by rushing on to land when conditions are not right for spreading or getting grass to grow.
If storage tanks are under pressure, then by all means spread a few loads at the first opportunity to lower slurry levels.
Ideally, target spreading the majority of slurry once soil temperatures start to warm up and there is less risk of overnight frosts.
Once soil temperatures reach 5°C, grass will start growing. Slurry applied at this stage will mean a higher nutrient uptake and ultimately, a greater response in grass growth rates.
Spreading slurry on duller, overcast days is also recommended, as there is less nitrogen lost to the atmosphere when compared with spreading on bright, clear days.
Targeting productive swards
Young grass with newer varieties tends to be more responsive to fertilisers applied in early spring. So, if ground conditions allow, late January and February slurry applications are best targeted to these swards.
Target swards with lower grass covers
Slurry should be spread on fields with low grass covers in early spring. These fields will be grazed towards the end of the first rotation.
By this time, early slurry will be washed in and unlikely to affect the palatability of grazing swards.
If heavy grass covers have accumulated over winter, the base of these swards will most likely be white, which will inhibit grass growth.
Therefore, it is better to graze heavy covers first, then apply slurry to the aftermath to get the best nutrient response.
Making use of LESS equipment
Low emission slurry spreading equipment (LESS) has become more common in recent years. While some farmers have invested directly in such equipment, the majority of this kit is in the hands of agri contractors.
On farms with larger, consolidated land blocks and a lot of slurry to move, consider making use of a contractor with a LESS kit to increase the nutrient value of slurry applied to grassland.
Contractor services come at a cost. But the time saving and lower requirement for chemical N may make it a cost effective option for some.