Making the nitrogen in your farm system go further – with minimal change to your existing management – probably sounds easier said than done.
But as one pasture expert explains, there are some relatively straightforward steps you can take right now to use nitrogen more efficiently in the season ahead.
“The first thing you can do is graze your pasture when nitrogen levels are low,” says Barenbrug Commercial Manager Graham Kerr.
“The second thing to focus on is prioritising feed quality, and the third is to choose ryegrass cultivars with efficiency advantages.”
Nitrogen levels in ryegrass vary as it grows and grazing with this in mind could decrease nitrogen leaching by up to 30%.
“Most of the season we graze ryegrass a bit too early. As ryegrass grows its nitrogen (or protein) levels drop, so grazing a little later, by about 0.5 of a leaf stage, means animals excrete less nitrogen in urine or dung.”
Graham says this is most easily done using tetraploid ryegrasses, often mixed with a standard diploid, because they remain palatable at higher covers.
Likewise, he says, making sure every mouthful of pasture on the farm is as nutritious as it can be drives efficiency across the whole system.
“Quality feed means you produce the same volume of milk with fewer cows. The better your animals are nourished, the faster they grow and the more milk they put in the vat. That means lower greenhouse gas emissions, and less nitrogen leaching.
“Pasture quality is all about consistent residuals. You set up quality by grazing well, which should be a focus on every farm, every day. But if you can add this to using tetraploids, which can give higher cow intakes, you double your benefits.”
Recent advances in plant breeding also have a significant potential role to play in improving nitrogen use efficiency, Graham says.
A new perennial ryegrass from Barenbrug, for example, has demonstrated an exciting ability to grow more dry matter than similar cultivars, with the same amount of fertiliser.
Sown side by side with its peers, on the same soil type, with identical application of nitrogen fertiliser, Array out-yielded the others.
“When its potential first became evident, we did a specific trial to make sure we were seeing what we thought we were seeing,” Graham says.
“Even more interesting is Array’s advantage over other perennial ryegrasses is greatest where there is nitrogen deficiency.”
Graham says in a farm system this means more even pasture growth at times when soil nitrogen is deficient, something that happens on virtually every farm at some stage during the year.
“Array’s higher nitrogen response is also a win environmentally, because you’re growing significantly more feed from the same amount of nitrogen.”
Array is the first ryegrass to come out of Barenbrug’s focus on breeding for environmental sustainability as well as plant and animal performance.
But the company has deliberately been using low soil nitrogen for the past 25 years to help identify the winners (and losers) in its ryegrass breeding programme.
“We’re tough on our up and coming ryegrasses,” Graham says.
“Any plant can flourish when conditions are perfect. Apply stress, however, and it’s a different story.
“We know when we graze thoroughly, limit the nitrogen and water sparingly, only the most resilient new ryegrass lines will shine. Those are the ones New Zealand farmers need.”
For more advice on managing pastures talk to your TSR or visit your local Farm Source today.