In this article, Teagasc outlines how you can reduce fertiliser costs on your farm.
Soil fertility status has improved in the last three to four years on drystock farms, with around 18% of soil samples being optimum in terms of their soil pH is greater than 6.3 and P and K at an index of 3, according to Teagasc beef specialist, Mark Plunkett.
“There is more improvement required; we still have a lot of soils at index 1 and 2 for phosphorus and again, potash being slightly better again; they are still 43%. There is still work to be done there on the basics in terms of improving soil fertility on drystock farms currently.” Mark told Catherine Egan on the Teagasc Beef Edge podcast.
According to Plunkett, having up-to-date soil analysis, reviewing fertility levels on your farm, and targeting nutrients appropriately to maximise the return on investment in P and K are the main ways to reduce fertiliser costs.
“Also, then choosing suitable fertiliser for the growing season ahead. It is best to contact your local advisor, and they will organise the taking of soil samples for you. A standard soil sample which gives you soil pH, lime requirement, phosphorus, and potassium costs €25 per sample.”
After taking soil samples
Mark highlighted that it is important to contact your Teagasc advisor when results come back and prepare a fertiliser plan.
“It will give you guidance to know how much lime is needed, where the slurry should be targeted on the farm and what bag fertiliser is required to balance soil fertility to maximise grass production during the growing season.”
“Lime is the starting point, and a pH of 6.3-6.5 must be maintained on mineral soils and peat soils a pH of 5-5.8. Lime increases the availability of major nutrients like nitrogen, phosphorus, and potassium.”
“For example, by maintaining the optimum pH on mineral soils we can release up to 50-60 units of free nitrogen from the soil organic matter on an annual basis.”
“Also, lime is key to the availability of phosphorus; you can unlock phosphorous in soil by optimising the pH. More importantly, to maximise the return on investment from bag fertiliser and organic manures, we must maintain soils in the optimum pH range.
Mark confirmed that farmers can apply lime any time of year, once soil conditions are adequate, and it does not interfere with grazing management on the farm.
He feels when paddocks are grazed out, it is a perfect time to spread the recommended amount of lime and when silage bales are cut. He recommends a minimum of three-months between applying lime and cutting silage.
Spring application of slurry is crucial to maximising the nitrogen recovery, Mark explained. He recommends spreading when soil and weather conditions are favourable over the coming months.
“The likes of your band spreader or trailing shoe reduce the surface area of slurry and in that, we capture more of the nitrogen in the slurry to grow grass. A key thing is to consider is the silage ground.”
“A key thing when we think about slurry, we should think about the silage ground, that is where the slurry originated with the grass that was cut, put into the silage pits and fed to the animals over the winter period.”
“Ideally to maintain the balance of nutrients across the farm, especially big nutrients like potash. We must return that slurry onto the silage ground to replenish the nutrients and feed the crop for the coming season.”
Source of nitrogen
At this current time, Mark feels the best course of nitrogen to use is an ammonium-forming fertiliser such as protected urea or cattle slurry.
“Now, there is a very low demand this time of year; we are currently waiting for soil temperatures to warm up and soils to dry out and get a good forecast.”
“Once weather conditions are good, we are looking at putting out half-a-bag of protected urea per acre. If your cattle have slurry available, you can put out 2,000-2,500 gallons, that will also supply the same nitrogen.”
“You can use protected urea right throughout the growing season. It is a very safe form of nitrogen when soils are cold and wet. You can use it right into the summer and back end of the year; it gives the same performance as a CAN fertiliser and gives a slightly higher performance from the trial work that has been done in Johnstown Castle to date.”
Mark explained that, traditionally, protected urea is 10 cents per kilogram cheaper than a CAN-based fertiliser.
“You can grow 10-15% extra grass on an annual basis by just getting the lime right alone. For me, the first place to start is to look at the soil test results put a plan in place to correct the soil pH in 2021.”
“The second-place then is to be looking at a suitable fertiliser on the silage ground or grazing ground. For example, on the grazing ground, a suitable fertiliser is an 18-6-12.” Mark concluded.