Increasing options for perennial pastures
Pasture Cropping into permanent pasture is an effective form of cropping on poorer sandy soils with low soil carbon and a high risk of erosion.
One of the most successful perennial pastures on sandy soils is kikuyu. Past research has documented the ability of kikuyu to protect soils from erosion and build soil carbon, while other work has shown that crop yields improve when cropping into kikuyu on poor sandy soils.
South West Catchments Council supported Evergreen Farming to demonstrate pasture cropping into kikuyu, and spoke to consultant Paul Omodei and farmer Bryan Kilpatrick about the practice.
Interview with Planfarm consultant Paul Omodei
What are some key tips to establish kikuyu?
The tips and tricks in establishing kikuyu is to sow at a shallow depth. For most perennials, one centimetre is the absolute maximum depth. I think most farmers have got the right gear to put seed at a centimetre. They just need to know the rule of thumb in establishing kikuyu, which is, if you think it’s just right, then lift the machine up a little bit more. It can never be too shallow, and almost on the surface is ok. It’s very similar to canola, so if you can sow canola you can sow kikuyu.
Also, if it is spring sown, try to get it established early enough to soak up enough of that finishing rain in spring. The later you go into October, the more of a risk it becomes unless you have summer rain. Generally speaking, in most areas of WA, and especially in the Great Southern, once you get into the September period, the feed pressure on the pasture system is not as great, so you can afford to take pasture out and re-sow it. That is quite commonly done.
The other thing to consider is your row spacing. As the machinery gets bigger and paddock sizes get bigger, you might be going out to 10 or 12-inch row spacing. If that’s the case, you’ll probably need to have a criss cross technique where you sow one way and then cross over the other way to make sure you get the density. Otherwise, having lines of kikuyu 12 inches apart is not going to be as productive from a density point of view.
What are some techniques for pasture cropping into kikuyu?
Kikuyu, once established, has a really strong runner system. If it’s in the first 3-5 years of establishment, you need to have either a coulter system or disc machine that can cut through so you are not ripping too much kikuyu out of the ground. However, as you get to longer stands – say 5 to 6 years plus, often a really good established stand of kikuyu needs a good ripping through with a tine.
The disc machines nowadays are quite accurate where they can put seed, so you can use canola or cereals into that system. But most of the kikuyu is being established on the lighter sands where it’s more likely to be an oat or a cereal rather than a canola. Possibly lupins – lupins have been trialled into perennials in the north, so if the soil type is good enough and not too winter-wet, then lupins may still be an option. That could be a win-win for a livestock system, having a legume for grazing weaners and also keep the soil together over the summer.
When can you start pasture cropping into a kikuyu stand?
Definitely not in the first 12 months. Get to at least 18 months after establishment, and then at the next break, so any time those early grass weeds are up and about.
I think the easier you can go in the first five years of kikuyu with knock down herbicide, the better off its going to be for its longevity. Obviously using heavier chemicals, like the atrazine’s and those sort of strong residual chemicals, that’s certainly going to hurt kikuyu establishment or longevity especially in that first three years at least.
We established a site in Kojonup. The next year, that paddock went to canola and the chemical control of weeds was done over the entire paddock. That was just too soon for the Kikuyu, which disappeared.
The lesson, and it’s something we probably already know as an industry, is that you need 12 – 18 months for kikuyu to establish before you crop into it. If you don’t have any summer rain and don’t get the density and thickness in the runners in the kikuyu, you are going to kill it with herbicides in that first year.
I think up to the first five years I would think that allowing a germination, getting an easy knock down for grasses, and then sowing oats or barley or something that can be a fodder crop for stock. If it’s going to be a grain crop then that’s fine too because that can be a good grazed stubble over the late spring into summer.
Interview with Arthur River farmer Bryan Kilpatrick in 2018
Note: The demonstration was in an unproductive paddock, described as Christmas tree type country with very deep sand. It was established to Kikuyu and serradella in 2008.
I used to crop the paddock but it was just a complete waste of time. It would hay-off very early and was no good at all. Then in summertime it was grazed and it would erode.
The kikuyu we have on there now is the best. It really does make a difference in terms of the competition with the weeds we have in the paddock. And it holds the soil together really well. It is a small paddock that is near the house block and I graze it as needed. It provides a bit of supplementary feed when perhaps things are dry elsewhere.
But by 2016, the paddock was probably getting to the point where it needed a regeneration. It was starting to get a little bit stale and needed something to happen to it. Our consultant Paul Omodei mentioned the pasture cropping idea and it seemed to be a good fit, and a good opportunity to see how it all works.
Paul suggested that I prepare the paddock by putting the kikuyu to sleep with Round-up. I was quite horrified but it really set the area up. We only sprayed it with 300 ml/ha. The spraying cleaned the paddock up and from a pasture cropping point of view, we ended up with a better result.
We put barley in with the kikuyu at 50 kg/ha which was probably too heavy. I think the kikuyu was struggling for a bit of moisture so I would certainly lower the rate. It probably should have been 30 kg/ha to created less competition for the kikuyu so it has a better chance to get away and perhaps a chance to see some more sunlight.
In terms of sowing into the kikuyu, it was pretty straightforward. I was quite surprised because of the way the runners are with kikuyu. I thought it might disturb it a fair bit. But our seeding rig is on 10-inch spacing and it seemed to flow through and it did a pretty good job without disturbing it much at all.
We left the livestock off for a good four months and then we gave them a light graze – it was only a very light graze and then it was another four months before we let them have another go. By then I had spray topped the barley and it was grazed at summer time.
I think it certainly helped with improving the quality of the feed in the paddock. I would certainly do it again and I see visually that it certainly worked and helped. And now I know that paddock isn’t tied to being pasture forever. I can still crop it occasionally.
The kikuyu is almost back to where it was beforehand when you compare it with unsprayed areas, and the competition from weeds in those sprayed areas is much less. We had a great stand of pink serradella last year (2017) all the way through the paddock. Again, that’s due to the spraying and less weed competition. It really gave it a chance to get away and looked really good.