Are you only applying nitrogen in early spring? Well, here’s a little secret – the best strategy is to also add early phosphate for both grazing and silage. You see, phosphate availability decreases when temperatures are low in spring. In fact, during April and May, grass can uptake as much as 0.6 kg of phosphate per day. But here’s the catch: the release of phosphate from the soil reserve is not sufficient at this rate of uptake. That’s where mineral phosphate comes in to top-up soil available phosphate, maximizing yield and herbage phosphate concentration.
Key Takeaways
The Need for Early Phosphate Application
On grazing farms, it’s crucial to apply a portion of your total annual P requirement in early spring, with the majority applied by April. Why? Well, a fresh P application boosts availability at a time when its natural availability is reduced by low soil temperatures. And by April and May, when grass growth is at its peak, there is a high demand for P.
The Power of YaraMila NPKs
Typically, fertilizers contain water soluble phosphate, which can create its own set of problems. When you apply water soluble phosphorus to the soil, it slowly becomes fixed by iron and aluminum. But fear not! The phosphate found in YaraMila NPKs is a mix of water soluble phosphate and di-calcium phosphate (DCP). Unlike water soluble phosphate, DCP is not fixed by the soil. Instead, it becomes available when triggered by weak acids from grass root exudates. This ideal combination of two phosphate fractions ensures superior availability of phosphate for grass during the crucial months of April and May.
Optimizing Phosphate Applications
Now, let’s talk about phosphate maintenance requirements. For grazed swards, the recommended maintenance requirement is 20 kg of P2O5 per hectare. However, if your grazing platform is producing 15 tons of dry matter with 80% utilization, then your maintenance requirement will be closer to 30 kg/ha. As for silage ground, the recommended maintenance requirements for the 1st and 2nd cut are 40 kg and 25 kg of P2O5 per hectare, respectively. Soil test results are invaluable for optimizing phosphate applications.
The Surprising Link Between Soil Phosphorus and Greenhouse Gas Emissions
Are you ready for another juicy secret? Recent research suggests that soil phosphorus levels have a direct impact on soil N2O gas emissions in permanent grassland. N2O is a potent greenhouse gas, making this research even more important. It seems that certain soil microbial populations, which are more dominant in low soil phosphorus situations, produce more N2O. But as soil phosphorus levels increase, these microbes become less dominant, resulting in lower N2O emissions. This research highlights the crucial role of soil fertility in the sustainability of grass-based production systems.
Want to learn more about grassland nutrition? Check out Ames Farm Center for additional information.
Now that you’re armed with these secrets, go ahead and plan your spring phosphate applications for lush, thriving grass!
