Using soil moisture and temperature data for optimising growth

Lisa Warn presents options to increase winter pasture growth.

Lisa: Right, finally found the right slides. Okay. So before we think about growing or when to feed, I suppose it seems like a dumb thing to say up front, but do you actually need to grow more feed, just because it's getting into winter and it's cold, things are pretty lean on the farm normally. But I suppose because a lot of people have been through pretty dry conditions in most of Victoria, and a lot of people have reduced their stocking rate. So some people I know are down 30, 40% in stock numbers, depending on what feed demand is on your property this winter, and how well your pastures are recovering from the dry, maybe you may not have to do anything.

So it's worthwhile doing a bit of stock take and a quick feed budget on a back of an envelope, and working at how much feed's across the farm, and some areas are probably still recovering from the dry. They might only have only four, 500 kgs on the farm, which is nearly a centimetre. Other paddocks, other farms might be bouncing around, 800 or 1,000 if they're lucky. So yeah, do a bit of a stocktake what's going around the farm, how well is it recovered, is it all filled in yet? Is there still gaps, that sort of thing in the paddock. Stock number, feed demand, and what are the pasture growth rates doing? You can measure them yourself if you're not sure what the pasture growth rates are, and how likely it is that you'll grow enough feed over the coming months, particularly if you're leading up to landing in July or August. You can use a tool called Pastures From Space, when it comes back online, and that was a really great product which I highly recommend once it's available again.

It's just in a bit of a transition to being given to or sold to a private provider from, used to be CSRO in WA. That tool actually has a satellite that goes over and you get weekly updates on feed and offer and pasture growth. If you subscribe, you'll get it at your farm level. If you don't subscribe, you just get trial level information, which is better than nothing, at least it puts you in the ballpark about what growth rates are doing.

But you can measure it yourself. If you go out measure a paddock, put a post or a tread in or something where you can go back to the same spot, come back in a week's time, two week's time, measure it again and you can quickly work out your own growth rates, which get you in the ballpark for feed budgets.

So next thing is, just thinking about what animals have to be going into those paddocks. Is it just dry sheep or lambing ewes? When are they going to be lambing, are they already lambing, lactating? How much feed do we need? If it's only dry sheep, they'd probably get by with just a bit more than that. If it's single bearing ewes that you're lambing, then they're going to need 1,000, couple of centimetres, and then if they're... can't see my own thing there. We need a head up here if you've got twiners, they're going to need up around that five centimetres. So who's going to need the feed and have we got enough time to grow that feed by the time they have to go in there, without doing anything, or do we need to do something to actually get that feed where it's in front of them.

So if you think about pasture growth rates, if you're not sure what sort of growth rates to expect, so you can do your little feed budgets, I've just got a pasture curve here for Bendigo with a well-fertilised phalaris clover pasture, and a similar one for Hamilton, but for ryegrass. So these are the kilos of dry matter picked here per day, and we can see, well-fertilised pasture might be growing at 15 to 20 kilos through the winter, around here. And similarly over here, in Hamilton, it might be doing a little bit better, a bit milder in the winter. But you can see the effect of this line down here, is a low fertility pasture, but the same good species but just being held back by yeah, low phosphorous or something like that. But you can see here that the growth rate's half that of a well-fertilised pasture.

So you know, you might go from growing 10 kilos a day to 20 kilos a day just by fixing up phosphorus or potassium or whatever the other macro nutrients might be. So we can do something about soil fertility and species, species will obviously affect the shape of the curve, and moisture and temperature. So at this end we know, yeah, it's usually not temperature, it's moisture that's holding things back. And then obviously when we get into winter, usually not moisture, but it's just temperature that are holding things back, and it depends what district you're in, how much that is being held back.

So if we want to try and grow more feed through that winter tight pinch area, that's just sort of... the bit that asides defines our stocking rate and that sort of thing, because it's the tight part of the year. We've got a few options. One is rotational grazing or autumn saving, and Andrew Whale's been talking about autumn saving. But we can use rotational grazing or autumn saving to try and create a feed wedge, that'll increase pasture growth rates, and we can build up that feed for animals with high feed demand such as the lambing ewes.

And this is an example of someone doing a bit of autumn saving that had stock in a containment area, they're just using their lane ways for containment, just holding them off, just trying to get that feed away, building up feed for later on when the ewes lamb. But the other options we've got are nitrogen and whether it's urea or liquid forms, and gibberellic acid, which is just a crystal that we mix up and put on with a boom spray. So I've just got two brand names here, one's ProGibb and one's Rise Up.

Okay. So if we've got a good pasture base, and we've got good soil fertility, we've got the options to use nitrogen or gibberellic acid and get really good responses. If we haven't got good fertility and we haven't got quite so good species, then we might get a response, but it just won't be the optimum. So it still might be economic, but obviously if we've got some better pastures, we can line up for these products. We're going to get a better response. So this is just kilos of pasture again, with that Hamilton curve. So here's the good fertility curve. So in, I suppose late May, early June when we've got moisture and it's still not too cold, we've got the option to use nitrogen to grow a bulk of feed, so we can be putting that on in here. And this little dotted line is showing you, if you put nitrogen on there, late May, early June, this is sort of the extra feed we could grow.

So we might go from growing 20 kilos a day to maybe 30 kilos a day growth rate. So it's pretty massive and we're just building up this feed and filling in that little feed gap there. If it's getting a bit too late for nitrogen and we're thinking it's getting a bit too cold, and this depends on where you live of course, then gibberellic acid becomes a good option. It works well when it's colder, so we can use it from June to mid-August, and then after that it's sort of getting warmer and we won't get as good a results from the gibberellic acid.

So we've got those two options and I'll talk about later where we can combine them or use them separately. Yeah?

Terry: This is all applicable to Southwest Victoria, true?

Lisa: No. Question was, "is this just applicable to Southwest Victoria?" No, don't panic. I did type Bendigo on the other slides. So it's really about moisture and temperature, which is what Jane was talking about with the database. So this is just, I suppose in terms of, you hear a lot about nitrogen, gibberellic acid, but often people aren't sure where they fit. So this is just me trying to show where they might fit in. And I suppose the other thing is if you're lambing in late July or August, if the conditions are right, you could have put it out here. If you're getting close to lambing and you're running out of time, often people think, well I got to go to gibberellic acid because I've only got three weeks before lambing, and gibberellic acid will work in that time. With nitrogen, we're really looking at six weeks leading time before we get the full response, that is. If we put it out and then graze in three weeks, we won't be getting the full response, the full benefit.

Terry: Gibberellic acid, is the form primarily best, I understand, with phalaris, particularly in the older varieties of phalaris? What about the winter active ones?

Lisa: Yup. So the-

Terry:That have already got these ...

Lisa:Yep. Yep. So the question was just about gibberellic acid, which I'll cover that in a bit more detail in a minute. Yeah, so whether they're like old Australian phalaris or winter acted cultivars, it works really well at a low rate. With the ryegrass, as in the [inaudible 00:08:50] for example, it works well, but you just use more per hectare. So it still works on the-

Terry: Even on the high-

Lisa: Yeah.

Terry: [inaudible 00:08:58]

Lisa:Yeah, yeah, yeah, yeah. It works on most species. It just depends on how much bulk you can grow depending on the species. That's all. So if you've got something that's, if you've got a good grass pasture, nitrogen and gibberellic acid will give you more bulk, where if you've got a weedy or more clover dominant pasture, you just won't grow the bulk. So they still might respond, but you just won't grow as much. So the cost of it is, it's not as cost effective. Yeah. But yeah, but that it'll work on those ryegrasses.

Terry: Do you usually combine them?

Lisa: I'll come to that, yeah. Yep. So nitrogen. Okay. So if you're going to use nitrogen, we want to have some good pastures, hopefully with some decent grasses in them. It doesn't matter whether they are annual or perennial. It could be annual rye, could be perennial rye, will just grow more bulk if we've got some grass sitting in there. And we want to have good background soil fertility, so we haven't gotten anything holding back the response.

When can we use it? So moisture and temperature are important. So we want to wait after the autumn break. We wouldn't use it straight away, because it's probably too dry. And there's also some nitrogen in the system from mineralization. So if we've had a dry summer, they'll be in, kicking around when the organic material is broken down. So when we get the autumn break, we have a flush of nitrogen's usually released. So you wouldn't want to use it straight away anyway, even if it was wet enough. Waiting a little bit of time is a sensible thing to do to use up the nitrogen that's in the soil, and then we might get, we'll get a better response. But we really need adequate moisture. So some parts of Victoria, people are sort of worried, they still haven't had enough rain to wet up to profile really well, but as long as you know the root zone has got moisture in it and the plants are actively growing and they are likely to regrow if you graze them, then you know it's okay to use it.

So the autumn break, it's usually touch and go and you probably wouldn't want to use it in anyway, because we've already got in kicking around in the system. So the pasture has to be growing. With our temperate grasses, it doesn't matter whether they're annual, perennial, ryegrass, cocksfoot, fescue, phalaris, any other varieties, they'll grow when the soil temps are above four degrees, they'll be growing. But to get better responses out of nitrogen there, you'd want to have the soil temp up around eight to 10, which it is kicking around at the moment, and in Southern districts it might even be 12. So they've still got plenty of potential to use if they've got the moisture. But some areas around that eight to 10 that that's when you get good... You could theoretically use it at four degrees, soil temp, but you just won't get as good of results with it.

Yeah. For people with subtropical grasses, obviously they shut down when the soil temp drops down below 10. So apply after grazing a paddock, so if you are rotationally grazing it works in really well, because you might have just grazed the paddock off, and then you can put the end on after grazing, and then not come back until the next rotation, which might be hopefully maybe six weeks in winter, which fits in perfectly with the time it takes for the nitrogen to give you a good response. And if you just come in earlier, you're not going to get the full response.

Measuring soil temperature. Yeah. Has anyone got a digital thermometer that they go out and... Yup. Yup. Do you use it a lot?

Audience: Most Monday mornings.

Lisa: Monday mornings? Yup. What's your soil temperature at 9:00?

audience: [inaudible 00:12:30].

Jess: Oh okay, good. Warm, yeah. So you can easily go out and measure your soil temperature with one of these guys, a little digital thermometer. If you haven't got one of those, you can have a look at the website Jane talked about, which the department looks after, and for those places in Victoria that soil temperature and soil moisture being trapped in those areas. But if you just want a bit more precision, grab one of these little guys and you can go out and measure it. A lot of the soil temperature stuff you read about is always like the nought to 10 at 9:00 AM in the morning, when people throw around soil temp figures.

So this is what Jane showed you before. So I'm just going to look at Baynton, which we thought, well it's a pretty cold place, 550 metres above sea level. And we've done a lot of work with nitrogen on Gerard Ryan's place. He's sitting there in the crowd. So if nitrogen's going to work you... this is pretty cold. So if nitrogen works here, then it's going to work pretty much in all these other places, I'd be pretty confident, because it gets pretty cold in the winter. So this is that graph again that Jane showed with Baynton, and the red line is that all a bit more noisy because we've got, that's a top soil. So it's changing in soil temperature during the day, and the other lines which are bit more stable during the day are the deeper soil profiles. So that's going back to March up till yesterday.

And as Jane said, it's sort of bouncing around, what is it Jane? Eight to 10, 11 or something like that. But with these graphs you can actually click on them to get a bit clearer picture. You can click on them to get... let's just pull out the top soil one, and also look at a smaller timeframe. So I've got rid of all those other lines. I'm just looking at the top soil, nought to 10, and you can see over the last six weeks or so, was up around 13, 14. Then it started to get really cold, and then it sort of seemed to have got back up again and hanging around that eight, 10 degrees.

If we go to the next one, that's just showing you over a day, the diurnal variation. Some days it could be four degrees difference between the high and the low of that of that day. So if you just do a check at 9:00 AM in the morning, that's what we usually talk about when we talk about soil temperature. When you read all research, trial information, that sort of stuff about responses.

So it's still, oddly enough this year, it's still reasonably warm and still capable of giving a nice sort of response to that climate. But other areas, like you said over there, it might be 11 degrees, and some areas might be 12 degrees at 9:00 AM. So easily warm enough for a nitrogen response.

So how much N do we need? So a lot of the nitrogen work's been done in the dairy industry, and a lot of it's been done by a fellow called Richard Eckerd, who's worked at Ellinbank and University of Melbourne. So I'm sort of drawing on some of his data here. This was looking at nitrogen responses, and on these bottom axis is the nought, zero kilos of N, up to 70 kilos of N. So I'm just talking about N, nitrogen. So if you're thinking urea, basically just double those numbers. So nought to 70, and this is the percent of maximum pasture growth rate.

So what they've tended to find is, if you put a little bit on, you sort of get less reliable results, you don't get as much response. If you put on somewhere between 25 and 50 kgs of N, you're sort of getting into this part of the response curve, bit more reliable responses. And then if you're putting on more than that, it's a diminishing return. So you're not growing any more grass and you're potentially losing nitrogen. If you got leechy soils, like sandy soils, you might be losing some N through the profile. So you're not putting up putting on heaps in one application, and if you put too little on you probably won't get the full, a good response either. So somewhere between 25 and 50 kgs, is a good good place to be operating.

And it depends on how much extra grass you need to grow based on your feed budget, whether you put 25 on or 50 kgs. So what product? Doesn't bother me what product people use, I'd rather them go for the cheapest. So usually your urea is the cheapest source of nitrogen, but if you need other nutrients, and you may look at other products because of that, some people are using ammonia sulphate, others might be using DAP. It just depends what other nutrients you're trying to put on at the same time.

And look, it doesn't matter what ... if you use the same rate of nitrogen, you should get the same response regardless of product. And even with chicken litter, I've had the same response where I've put on the amount of chicken litter, and matched the nitrogen in chicken litter to urea, I've had exactly the same response. So that's a good sign. If you're using, just pick the cheapest product or what works for you depending on other nutrients.

So here we are at Baynton, so like I said, can get pretty cold in the winter. And these are just some results from a few years ago, 2015, '17, looked at putting your urea on, 100 kgs of urea in late May, early June. So obviously once there was enough moisture and the pasture was growing and not moisture stressed, just timed it based on those conditions. Measured the response six to eight weeks later, and these are the sorts of range in responses, grew an extra 400 to 700 kgs per hectare, which equates to eight kilos of dry matter per kilo of N. Or 14 kilos of dry matter per kilo of N.

And that was pretty similar, consistent with a lot of the dairy work relate, they're always looking at ryegrass in dairy systems. But eight to 14. They often talk about 10 to one responses in the late autumn, and then if you haven't got great species or slightly lower fertility, you might be going down to five to one. So if you sort of can think about those sorts of responses, it allows you to do your budget to work out whether it's economic or not. Yeah, sorry?

Audience: What's the phosphorous level of that, of that paddock?

Lisa: Oh about 20 or something. Yeah. So per K, is not limiting. Yep. And can you see there, this is a replicated experiment. This has had all the nutrients, so nothing limiting. And if you can see that line there, there's actually a string there, but this side's had urea and that hasn't, but it's a good phalaris pasture. It's responded really well. Can you see the difference? Yeah. So the extra 600 kgs in that particular photo, which is worth, it cost about 10 cents per kilo of dry matter. So pretty, pretty cheap.

Audience: [inaudible 00:19:38].

Lisa: Oh, in this particular one it was probably, I don't know, 70, 80.

Jane: But it doesn't have to be.

Lisa: Doesn't have to be that strong when you put the urea on, as long as there's decent grasses there to respond.

Audience: [inaudible 00:00:20:01].

Lisa: I haven't in these trials, but just drawing on other people's experience. But did you want to make a comment or?

Audience: No, I was just asking if you had any comparison. Just due to growth or-

Lisa: Yeah. Look, and this is using urea, so once again the timing's got to be... you got to be planning ahead a bit more to get the best results from it. And I suppose when I talk about gibberellic acid in a minute, a lot of people have been using the easy end type products because they can mix them with the gibberellic acid and get it out at the same time. So that's one reason why people are using those products. It is a dearer form of N, that's the only thing.

So just depends on the timing and how much extra feed you're trying to grow and how it fits into your system. But just the other thing I wanted to point out about nitrogen is that a lot of our good, well, a lot of pastures that were good had deteriorated and getting filled full of junky grasses like silver grass. This is silver grass. This is near seymour or Glenaroua, 2012, I was doing some work over there. But it was a pasture that was, in the autumn the was phalaris quite small and stunted and it wasn't that dominant, but there were plants there. But the silver grass was quite, dominant, and PKNS were all really good, but it was just a bit deprived of nitrogen. So a lot of our good pastures, potentially good pastures are deprived of nitrogen and they're just not performing.

So if we can somehow get the nitrogen cranked up, whether it's more clover or using urea or other products, then we would get a lot more out of them. But this all happened in this particular trial was, in the autumn 25 kgs of N and urea form was added to that. And this one didn't have any urea, but the background PKNS is really high, and so by the spring, so really good in responses during the winter, and by the spring the phalaris had then suddenly out competed the silver grass. So it was just lack of N. It just wasn't doing much. And the silver grass was getting the advantage because of the lack of N, and the landholder had been using Simazine every now and then to try and clean the silver grass out, which just kept coming back all the time.

So this is a really good example, if there's a nutrient constraint there holding back your good species, you may not have to be spraying out the weeds. So this was a classic silver grass hanging around because of low N, and it actually turned out there was a molybdenum deficiency going on in this paddock, it needed moly. So that was another reason why it was so in deficient. So don't forget about molybdenum too. We can talk a lot about the macro nutrients, but don't forget moly.

Audience: Lisa, what are your thoughts on soil testing versus tissue testing at the relevant time of the year? [inaudible 00:22:45]

Lisa: Yeah. So the question is about tissue testing and soil testing. Soil testing is good for Ph and macronutrients and some structural things. Leaf analysis is good for trace elements. So if you're not sure about moly, copper, boron, zinc, go leaf test. You get some of that information on a soil test, but leaf test is more accurate. Spring, leaf test in spring before the clover flowers, and soil test, I usually go for spring too, just because the ground's soft and you get your results back before your autumn fertilising programme.

Audience: Is the data showing that over a number of years, a period of which the soil temperature is super firm. And so [inaudible 00:23:32]?

Lisa: Is the question-

Audience: Soil temperature might be a rotational [inaudible 00:23:42]. So is the data showing soils are staying warmer longer, or?

Lisa: So the question is about soil temperature, is the data showing... Yeah. I don't know. We haven't gotten enough data from those sites that Jane's talking about, they've only been in for... not even 18 months, I don't think, have they?

Jane: [inaudible 00:24:03]

Lisa: Yeah, less than a year.

Jane: Nearly two years.

Lisa: Yup. Yup. But I suppose we could look at ambient temperature as opposed to soil temp, but yeah. It's easy to get air temperature records that are easy to get soil temp. So that's why these sites are going to be really great to have that information.

Jane: Cropping sites have been here for a lot longer.

Lisa: So Jane, the cropping sites have here for-

Jane: Well it's not cropping sites, I'd be able to show you [inaudible 00:24:32]. These little cropping sites, but these are three weeks on moisture. [inaudible 00:24:39] a lot longer, so might be years [inaudible 00:24:40]. I think it might be on those sheets, otherwise I'll have to give you that next week of course.

Lisa: So was the... Terry that question was in relation to, does that mean we've got more option to use nitrogen because the soils are getting warmer? Is that-

Audience: [inaudible 00:24:57].

Lisa: Theoretically with climate change, we're meant to be getting warmer winters, which is meant to help pasture growth and also more CO2, which is meant to help pasture growth too. So all the modelling shows that with climate change we would expect more winter growth, but more variable rainfall and as springs worse and autumns worse that we might get... so it's probably not much of a consolation, is it?

Audience: [inaudible 00:25:25].

Lisa: Yeah. So if we're talking about nitrogen responses, if you're trying to plan for your situation, what numbers to chuck into a little budget to work out the maths, whether it's worthwhile or not. If you've got some good pastures, with good background fertility, so some grass in it, it doesn't have to be wall-to-wall sort of perennial as long as there's some grasses there, because as I showed, it may not be great now, but if you do put some N on and then rest the pasture, you might find those grasses get stronger. So you don't have to use herbicides to take out the weeds.

So if we're working on a maybe bit colder, if it's getting a little bit cold or something else that's holding the pasture back a bit, you might work on five. These are sort of typical numbers, and in Spring if we were looking at fodder conservation, you want to grow a bit more grass, then often you see numbers like 15 to 20, but I'm not talking about spring today, just about the winter.

So if we got a five to one response and we just, for argument's sake, say we're going to eat all the extra grass we grow, if urea were 600 bucks a tonne, it's about 25 cents a kilo of dry matter, that it's costing us to grow that extra grass. Which is about 2.3 cents per megajoule. If we get a good response, like I've easily shown we've been getting at that Baynton site, which is pretty cold in winter, it's 13 cents per kilo of dry matter, which has 1.2 cents per meg. And if you compare it to grain at like this recent prices, you might be paying more than this, 43 cents a kilo of dry matter, 3.3 cents per meg.

And if grain's a bit more reasonable price, .31. So even if grain was cheap, you can still see, even if we're not getting quite an amazing response, nitrogen at that price can be still cheaper than grain and even obviously when grain's really expensive then it becomes an option. But if we don't have moisture, then we can't use it, we still got a hand feed. But I suppose the beauty of, if you've got the moisture and the temperatures okay and we can grow a bit more grass, at least this gives us the option to pull back on the supplementary feeding and hopefully not be doing it when we're lambing. So we don't have to be trough feeding, we can build up enough feed and then we can lamb onto the grass, and not have to go near the ewes.

Just a little bit on losses from urea, because lot of work they've done in the dairy industry, and just the general wisdom is, if we're urea when there's actually moisture, through the autumn, winter, the losses from a ammonia lateralization, they're going to be quite low risk. In the dairy industry, they're often using nitrogen in the warmer months. So the risk is a lot higher, but I think most strict beef people wouldn't be using it in that period. So the losses are going to be quite low. They're only talking three to 6% losses in a lot of work done in the dairy industry. So it's not a lot. And it's still, even if you get a bit of a loss, it's still cheaper than feeding grain most of the time, or hay.

So just a bit on, any questions on N before I just move onto the GA? And then I'll talk about GA and N because that was a question that someone had earlier on. So, gibberellic acid, if we're thinking it's a bit too cold in our environment or we're getting too close to when we need the extra feed, we've only got three weeks and we're going to lamb for example, then we might, and it's cold, we're well into June and the temperatures are dropping, and we think it might be too late for N. And then we could look at gibberellic acid. So it works well when it's cold or too cold for the N to work really well. But gibberellic acid is just a natural plant hormone. So it's in the plants naturally in the warmer weather, and when the weather is colder, the levels of gibberellic acid in the plants is lower, hence if you put GA onto the plants, it tricks the plants into thinking it's the warmer time of the year.

So what it does is it stimulates cell expansion. So you tend to get leaf elongation and that increases the growth rate and the kilos of dry matter. It's been around for a long time and used in horticulture. CSIRO did some work on pastures back in 1958, they used some pretty high rates, but they got good responses back then. So it looked promising. They were getting like 400 kgs dry matter extra, and that would have been older strain phalaris in those trials. But back then it was just way too expensive to be able to use. It wasn't a feasible option for pastures in those days. So that's changed now and it's now quite a cheap product.

So where can we use it? So pretty much similar rules to the nitrogen story, we want to have better pastures, better grass in them. Good background, soil fertility. So same rules as N, and with phalaris, very responsive. So it doesn't matter which cultivar, the old Australian responds really well, and the winter actives do too. You can get away with 10 grammes per hectare, if you're talking perennial rye or cocksfoot on the other grasses, it's more looking at 20 grammes per hectare. You can do your own trials and on your place look at what rates you can get a reasonable response with if you're not sure, but these are pretty much the standard starting point on the label, and putting it out in a water rate of a hundred litres hectare. So when, the timing's important. The pasture has to be growing, we have to have enough moisture so we can't have moisture stressed plants, but we can put it out when it's too cold for the good N responses.

So June, July, up to mid August, and then it might be getting too warm after mid August to get really good results. So best results if the air temp's kicking around five to 15. Yeah and average soil temp above five degrees. Like nitrogen, if we're on a rotation, we can graze the pasture off and then put it on after grazing and let that pasture rest for at least three weeks, maybe four weeks, to get the full growth response, before we come back and eat it off. But you need a little more leaf than you'd probably get away with with nitrogen, just because it's got to go in through the leaves. So I'm saying minimum of 800. Some stuff you read's 1,000, but most people don't have 1,000 kilos left after the they've just grazed the paddock. So just want some leaf for it to be taken up.

Apply to dry leaf. And if we've had a frost, probably just wait a couple of days for the plants to recover a bit. And like I said, if you can take stock out for the 21 til 28 days just to optimise that response and then it's worked through the plant and then it's ready to go.

So this is that same site at Baynton, looking at gibberellic acid. People have used gibberellic acid before? Yup. Yeah. So you're all familiar with the colours of the leaves when you use it, you get the cell elongation, so you stretching out the chlorophyll in the leaves, in the cells, so it tends to go a bit yellow. So you can see that yellowing there. In this case, grew an extra 200 kgs of dry matter, which is costing 11 cents per kilo of dry matter or cent per megajoule of energy.

So in this, phalaris pastures tended to get 200 to 300 kgs of a dry matter of hectare extra. The CSIRO stuff said 400, the old work did 400 kilos. So, in most other trials I've seen people report on it somewhere of that order, you know, 200, 300, 400. I haven't seen any higher results than that. So you're not going to grow the same bulk that you would with urea, but like I said, if it's got too cold for urea and you're running out of time, then it's still a good option, but I just think you grow more bulk with your urea, if you can use urea at a good time. But even in sub clover, I've had responses on sub clover pastures too and I've seen other work in South Australia where they've used it on medics and got similar sort of risk results. So most things will respond to some extent.

Okay. So got the N, we got the GA, and then a lot of people are mixing them together, using like easy N products and liquid forms of nitrogen, and mixing them together and putting them out then. And that's convenient. If they've got their own boom sprays, they can put them out together. The liquid nitrogen is a dearer form of in, but you've got the convenience of being able to put them out at the same time. A lot of results I've seen on where we put them together, sort of inconsistent results from whether they combined, some trials show no extra response, of having them together compared to just GA on its own, and others show up to 300 kilogrammes.

So if we're sort of getting that, if we're putting the nitrogen and the gibberellic acid on together and we're getting you know, 300 kgs extra, that's worth about 15 cents a kilo of dry matter. So it's still a bit more expensive but still, you know, reasonable value for money. So I've just tried to drag out some figures from different trials where they've been used together and looking at the extra amount compared to just using GA on its own.

And this is just one, the people that make ProGibb have got on their literature. They brought an extra 200 kgs of grass by putting urea and GA on at the same time and measuring it four weeks later. Just some of the work that I've been doing with urea and GA at the same time, but measured at six to eight weeks later to give the nitrogen a chance to work through, you know, 80 at one one trial, 100 to 200. And then where I use urea at the optimal time and then came back and just put the gibber, I guess around the optimum time and then measured it six, to eight weeks later after putting the urea on, 30 at one side and 300. And then Andrew Spiers ran a trial a number of years ago where he put on nitrogen and GA at the same time in the mid-June and measured it three weeks later and got no, no response to the nitrogen.

And that may be just because it needed another few more weeks for the nitrogen to do something. So if you're coming in after three weeks, you probably just capturing the, the GA response with the nitrogen, it's probably, you know, taking more time to work through the system. So yeah. So it's sort of inconsistent results. But, and look, like I said before, if you're in doubt, you can always just run some strips out yourself and just check what sort of responses you're getting. Just to give you confidence about what you need to use them in combination or just one at a time.

So if you're coming in three weeks after they've been applied and then having to graze it, that's fine. For the GA, it's already done its thing. But you just saw like diluting out some of the nitrogen so you probably not getting the full umpf from your N, and whether there's a little bit left in the soil, that's I think, because the N pretty much gets into the plant within two to three weeks, the bulk of it's probably working its way into the plant.

So if you're coming in and grazing a bit too soon, you're probably just diluting their overall N response. But yeah, if it's helping you maintain your rotation at all, that's a good thing because that's, that's a difficulty, isn't it? Is trying to keep something going through that winter.

audience:[inaudible 00:36:23]

Lisa: Yeah. Okay. So just, like, it's pretty easy to do this. Sum's on the back of the calculator that, I mean you know what the products cost. That's a, that's the easy bit. You know what the boom spray costs, you know what the spreader costs. It's tougher just knowing what the response is going to be. So that's all I've just tried to do today is just give you some feel for what to expect if you get the timing right and the pastor's right, but there is a little calculator on this website. Evergraze website, it's a little ribbon and you can go in there and you can just plug in the cost of urea or the cost of the Gibberellic acid, or doing both together.

Whenever you are having a look at, and then just put in a expected response and it'll quickly work out the cents per dry matter that it's costing you and the cents per megajoule. So you can have a play around with that. And then you can look at, well you know, if I think it's a bit cold for N and I only get a five to one response, is that still better than grain or hay? You can just play around with those numbers just to give you a bit of confidence whether it's going to be worthwhile or not.

Yeah, and by all means, if you've not sure with different rates and things or combinations, do some do some test strips. That's always really a good idea. To me, when I've done those trials, or I wasn't factoring that into a large extent and it does get pretty frosty right into the trials, but that's just, you know, this, this practise sort of recommendation.

Yep. Okay. So just to wind up, importantly, do your feed budget so you can work out how much, how much is that fee gap? Is it, is it a 300 kilos feed gap? Is it a 500 kilo feed gap? And then that way you can say, well, if I plug it in with GA or what rate of N do I have to use to fill that gap? So if you can do some of that number-crunching that's a good place to start. How fast do you need to feed? Do you need it in a hurry, which is pushing you into using gibberellic acid I suppose, and maybe putting a bit of in at the same time, what sort of responses you likely to get?

Yeah, you can certainly grow more kilos of dry matter from urea. Then you can GA, if you can put the urea on at a good time. And look, regardless of which one you're using, you get some response. And it usually works out cheaper than feeding grain or hay, even at those variable prices. So yeah. Thank you.

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Page last updated: 02 Jun 2021