Maintaining nutrient application on-farm this spring is essential to optimising soil fertility, farm production and profitability so you can take advantage of high commodity prices. Despite the uncertainty we’re facing, now is not the time to pull back.
One great option to maintaining that fertility is superphosphate. When compared to other sources of phosphorous (P), super is the best value by far. There’s a reason it is a trusted nutrient and has been the backbone of New Zealand agriculture for decades.
Easing back on the throttle
We spoke to Mike Grayling in late-2021 and his experience continues to ring true this season.
When dairy farming in South Taranaki’s summer safe Awatuna district, it’s tempting to pump up the volume of N in the annual fertiliser mix. It’s worked well in the past for Mike, who owns two dairy farms mid-way between towering Mount Taranaki and the coastline.
But with one eye on the national N-cap of 190kg/ha/year, Mike is moving to a more tactical approach for applications of N combined with up to three dressings of 30% potassic super across each property.
Optimising legume growth and function
Most local farming systems rely heavily on pasture legumes to increase and maintain the soil nitrogen (N) pool. It is the size and rate of turnover of this soil N pool that is often the primary determining factor in how much pasture a farm will be able to grow annually.
Optimising the growth and function of the legume to be able to fix N requires a good supply of P and sulphur (S), as well as other major nutrients and trace elements.
Superphosphate, a multi-nutrient fertiliser, has been and remains an excellent way to enable pasture swards (that contain legumes) to fix atmospheric nitrogen. The balance of nutrients in super (P, S, and calcium (Ca)) suit most New Zealand soil types and you can be confident the numbers stack up.
Sustained value
The key features that have sustained the value of superphosphate in New Zealand for pastoral farming since 1881 are:
- Its chemical composition: 9-10% total phosphorus, 11-12% sulphur and 20% calcium, all in readily plant-available form
- It is fully effective in a wide range of soil and climate conditions
- It does not of itself affect the acidity of the soil
- By encouraging plant growth, it also encourages populations of introduced surface-casting earthworms and increased soil microbial numbers and function.
- It also contains gypsum (calcium sulphate) which plays a key role in improving soil structure, aeration, and water retention.
Using superphosphate and decoupling your nitrogen from your phosphate also offers greater flexibility when looking to remain under the 190kg/year nitrogen cap.
Speak with your agri manager or the Customer Centre on 0800 100 123 for advice on what’s best for your farm system so you can have the confidence to maintain your production.