Grow the future

Grassland - adapting fertiliser applications to optimise growth this season

July 09, 2020 Yara Agronomy Team Episode 3
Grow the future
Grassland - adapting fertiliser applications to optimise growth this season
Show Notes Transcript

With many livestock farmers facing reduced grass growth so far this season Philip Cosgrave Yara's Grassland Specialist takes stock of this seasons silage campaign and gives advice on how farmers should be adapting fertiliser applications to cope with the conditions this season.

Ken Rundle:

Hello, my n ame's Ken Rundle and with me today is P hilip Cosgrave Yara's country grassland agronomist, P hillip. This is a busy time for all those with grass to manage, but I suppose one of the most obvious things just now is silage, so let's start with that.

Philip Cosgrave:

Yeah. A lot of farmers will be quite disappointed with their silage today. We had a very, em growth started quite late in the spring and a lot of the traditional first cuts that would have been taken in mid May or towards the end of May, would have been lighter than normal. But those who were, would have been looking to cut, um, earlier on and may actually had pretty good years, but I guess the, the, the, the shortage of, of hay and that we've all experienced in that kind of in that may into June period, um, has really impacted on, on second cuts to the extent that, you know, some, uh, fertilizer applications and second cuts have been delayed. And that also goes with, with organic manure applications because of the issues around, about applying organic manures and the contamination of grass, and for that second cut been harvested. So, uh, I guess from a fertilization point of view, if we're looking at, you know, looking at, uh, at this stage, we're looking at some it's unlikely, the third three, the third cuts have been taken at this stage because just the poor growing conditions in, in, um, in, in June. But I suppose where, where we have taken cuts of silage, it's important we're going to, um, fertilize for the next cut. Potassium is one thing that if you have got low potassium index soils, um, it's quite important then if you can't get out with organic, but manures is quite important anywhere to use, um, a silage grade fertilizer product with a bit higher, um, with some potash in it, because basically potash will help, you know, the grass plant cope with these dryer, um, conditions. And also for, I suppose, the where in, in where second cuts didn't receive any organic manures, you know, that'll help replenish soil K's also with, with them, for nitrogen applications, you know, for multi-cut systems, we're looking at that for that two units per day or two and a half kgs per day plan for that. Um, and I guess the other thing is to use a, an ammonium nitrate based fertilizer because of the low risk of, of ammonia loss for them. And they're more stable in, in, in, in those conditions. So overall, you know, if phosphate is required in those low index situations, I would say put on that, you know, use a, uh, an NPK, um, with sulphur, but yeah, but it is quite challenging, I think, um, for, um, a lot of farmers trying to look at our clamp and looking at us, you know, the amount of silage that they'd normally have in it, I think, um, you know, it is going to be a worry. So it's important to fertilize, those that next cut, um, to try and, you know, build, um, you know, build yield to make sure because there will be some, I suppose, generally after a dry period there that we've experienced and that June that we do, we've got to kind of compensatory growth.

Ken Rundle:

It's stress all around isn't, it it's stress on the grass, it's stress on the farmers. And it's that to bear in mind, hence t he, the advice on the potash t hat the point is you're not dealing with a grass crop, that's just going for it.

Philip Cosgrave:

Yeah, that's it, they've, they've found, there's a lot of research to say that, you know, if you keep nitrate levels up in the soil and it helps actually maintain grass quality, um, where, and if there's, um, you know, dry conditions, choice, select conditions, I would say that's a good time can to maybe look back on, you know, your applications to date and if you've missed applications. But what you're looking to do is you're looking to try to, at this stage, um, in July, you know, for those aftermaths, it's important to get some, some available nitrogen in the form of ammonium nitrate there and get those aftermaths growing quickly so that you can get stock out to grass, um, without delay. And I would say that, you know, do an exercise on the back of an envelope and, and look at what the off takes may have been in the previous silage cuts. So you're looking at, um, for, you know, a ton of, of, of 30% grass of, you know, if you're taking fresh weight and in a ton of silage, and you're talking about 2.3 kgs of, of phosphate and around about 10 kgs of, of, of care to all coming off in a, in a, in a ton of, of grass or silage. Now, for those of you listening in, in, in the South of Ireland, well, that's more like a, um, for elemental phosphorus, it's a kg of phosphorus around about eight and a half kgs of, of, of, of potassium. So there's significant offtakes. So it's a good opportunity now to actually use, um, a product and replace some of that potash, or you think it needs replaced, you know, for that matter phosphate as well.

Ken Rundle:

There's a tendency to forget that every crop you take off, it's also taking the nutrients, not just the value of the crop to the stock.

Philip Cosgrave:

Yeah. And if we look at, we take the difference between, I suppose, the off takes from, from, from signage and grazing. So you have to take off two and a half times more phosphate where you take stylish and 10 times more potash and in comparison to, to grazing when we're taking silage off. So it's important to, you know, to balance the books,

Ken Rundle:

Sulphur is something you haven't mentioned so far, but it most soils in the UK and across Ireland as well are deficient in sulphur to some extent. So what's your advice on that,

Philip Cosgrave:

But we're looking at, as I suppose, a full season response to sulphur, and we're not getting the sulphur that we used to get in the, in the past through atmospheric deposition. Um, um, the other thing that we, we have to take into account is that a lot of instances, we're growing more grass, we're managing grass better. So that puts a higher requirement for, for solid sulphur. And I guess we have to treat the, you know, the grass takes off sulphur in sulphate form. And I suppose it's important that the fertilizer we use that the sulphur is in it and sulphur form, but sulphur, um, is, is very much like nitrate in the soil. And that if you over apply sulphur, you can't carry that sulphur on to next season because it's, it will be leached out the soil profile over the winter months. So, you know, at Yara, we talked about this little and often approach that you feed the plant as, as, as, as, as the plant requires. So we have, I suppose we have chosen that most of our grades now have sulphur for, in them for that matter. So you're, you're continually feeding the plant with that sulphur that it requires. And we see that sulphur, you know, helps in, in, in, in utilising nation more efficiently, but, you know, and that's giving back, I suppose, greater yield per kg of nitrogen that's applied, but also, um, better quality. So where are we tendency where we see the sulphur deficient swards, we see, um, you know, lower protein levels. So it's a part of to keep that up. And I suppose what happens now is that with, with the warm soils, we've had above average soil temperatures for this time of the year, but a lot of the mineralized sulphur has actually kind of come and gone. And so, and that we've seen that in, in, in trials that we've carried out in, in, in Northern Ireland in AFBI and Lough Gaul where we can see that kind of peak in sulphur mineralization. And then when we get into July and August, we see the, um, the actual mineralized sulphur decreasing. So it's important to keep that topped up with mineral N application.

Ken Rundle:

Are there any reminders for the intensive grazing guys that people who are working hard on maximizing their grass use?

Philip Cosgrave:

I suppose whether you're an intensive grazing or you're, you're more extensive, I suppose, the, um, the intensive grazers out there, you know, you still have a lot of, of, of rounds to go still, a lot of grass to be grown, you know, into, we hope into September, October, but I suppose it's important to, to, you know, to once at this time and going into August that we're, we're looking at actually, you know, building grass on the farm until August, you know, on an apply, I suppose, fertilizer to build, um, grass going into this, you know, into this August period, because I'm often asked about, you know, applying nitrogen, you know, in, in September and, you know, even the end of September where it's allowed and really the response to nitrogen applications are less at that stage. So, you know, you got a fire, you get far more, I suppose, kgs of dry matter for a, for a kg of nitrogen applied in August, then you will. And at the end of September into October, so we can build grass, grass will maintain its quality in August time. And, and then we can, we can allocate that grass then as we go out into, into late autumn.

Ken Rundle:

Philip Cosgrave, thank you very much. And that's all we've got time for, but don't forget. Our next podcast goes live on the 23rd of July when we'll feature potatoes, join me, Ken Rundle then Thank You