Now that the slurry spreading period is only a matter of days away for farms in Zone A, farmers needs to put a plan in motion to get the timing and spreading of their slurry right this spring.
The use of Low Emission Slurry Spreading (LESS) has become compulsory on farms stocked at 100kg N/ha or above from January 1, 2025.
In 2024, this rule applied to all farms with a grassland stocking rate greater than 130kg N/ha.
Slurry is a very valuable source of nutrients on the farm and can be a huge addition to grass growth in early spring if it is applied correctly and in good condition.
At current prices for nutrients, applying 1,000gal of slurry at 6% dry matter (DM) to grass is equivalent to a 50kg bag of 9-5-32 fertiliser when applied correctly.
Timing of slurry
It is easy to talk about when the best time to get out slurry is, but the reality is that farmers will have to spread slurry as soon as the spreading period opens up, due to full tanks in the yard.
If this is the case, farmers should be examining their slurry storage for next year to see if there is any clean rain water entering the tanks and impacting storage.
If you have to get out slurry early and the conditions might not favour spreading, spread well away from rivers, streams and flow channels and try to target drier paddocks on the farm.
However, if you are not tight on space and can afford waiting for better conditions, farmers should be spreading when soil temperatures are consistently at 6℃ and rising, as it means that grass is growing and has the potential to take up nutrients.
The timing of slurry application has a large influence on the uptake of nutrients by plants and the potential for losses to waters.
Another factor that has to be considered is the soil moisture content of the land, as if the soil is saturated, going out with a tanker will cause structural damage and will lead to surface water runoff.
It is especially important to check the weather and the soil moisture content prior to spreading when using an umbilical system, as it allows slurry to be spread when a slurry tanker wouldn’t be able to, due to ground conditions.
Targeting paddocks
The first few paddocks that slurry is being applied to this spring will have to be chosen carefully in order to he fully benefit from the slurry application.
The first few paddocks that should be targeted should be fields that have a requirement for phosphorus (P) and potassium (K) and with a good pH.
These fields should ideally be drier fields on the farm, with no drainage system in place and away from streams and rivers.
Farmers should avoid spreading in paddocks with high connectivity to the drainage network or fields with critical source areas until later in the spring when their is a lower risk of nutrient loss to water.
Farmers should match the rates of application of organic fertilisers to the growth rates of the grass, which is important in the early spring period where growth rates are at their lowest.
When 2,000 gals/ac is applied using LESS, it will supply around 20 kg/ha (16 units/ac) of available nitrogen (N)
When 2,500 gals/ac is applied, it will supply around 25kg/ha (20 units/ac) of available N. Manage slurry application to ensure that no more than 2,500 gal/ac are applied in each application in the early spring.