- To prepare for effective seedling recruitment, try and clean paddocks of annual weeds in the year prior.
- After seed has been dropped, heavily graze the paddock through summer and in early autumn to get the pasture into an appropriate state for seed germination.
- Smaller paddocks or temporary fencing aid in grazing control, as small mobs are more manageable
- If small paddocks aren’t available, slashing later in the season can help to remove excess dry feed. ·
- Check out the How do I optimise seedling recruitment to avoid resowing fact sheet for more practical tips.
Seedling recruitment has become a valuable tool for Victorian lamb and beef producers Colin and Jill Frawley to rejuvenate thinning ryegrass pastures.
From 2015 to 2017, Colin’s South West Prime Lamb Group undertook a series of trials investigating potential methods for improving perennial ryegrass persistence. One of the methods explored on their property ‘Wirra’ was the strategic spelling of perennial ryegrass to encourage seedling recruitment.
The alternative to seedling recruitment is resowing, which is high cost and involves taking a paddock out of production for an extended period – something Colin would rather avoid.
Here, he discusses his approach to seedling recruitment and his tips for getting it right.
“In preparation for seedling recruitment, you need to plan ahead,” Colin said.
“Earmark potential paddocks in the year prior to treatment, and make sure that any annual weed issues are addressed in advance.”
At Wirra, silvergrass can be an issue, so Colin does a late winter/early spring clean with Simazine in the year prior.
“Barley grass may also need to be controlled with pasture topping or a selective herbicide like Shogun®. Silage is another good way of thinning out annual weeds,” Colin said.
Because surplus feed is essential when undertaking seedling recruitment, Colin said his approach to deciding on a year is ad hoc so he can see how the season is eventuating.
“I need to feel that we can do without a paddock for a couple of months. If it’s going to be a tight spring, delay for another year,” he said.
Encouraging seed set
Another key element to success is heavy grazing in early spring to ensure even seed head emergence – Colin aims to graze the pasture down to about 2,500kg/DM/ha before locking up.
“If you have a paddock that hasn’t had a lot of stocking pressure on it and is out of control, it’s not a good candidate for seedling recruitment,” he said.
The target paddock is taken out of the grazing rotation from around the end of October or the start of November and spelled for seven to eight weeks to allow for full flowering and seed set. This takes the pasture through until the end of December.
In the original trial, after seed maturation, mesh was dragged through the dry ryegrass to knock the seed to the ground. Colin has refined this process, now using an old tedder rake to dislodge the ripened seed.
If the extended period of lock up is a concern, Colin recommends watching the seed formation carefully, as the process can be hastened by waiting for the right weather conditions.
“Once the seed is mature, wait for a hot, dry afternoon, when the stems and seed heads are drier and a little more brittle, then running the tedder over the paddock easily dislodges the seed,” he said.
“If you’re not pressed for feed, the alternative is to leave the paddock locked up and let the seed drop naturally.”
Colin recommends heavy grazing when the seed is on the ground, so that come April, the paddock isn’t full of dead grass, is well grazed and has lots of hooves over it.
Post autumn break, the conventional recommendation is to spell the pasture, but Colin is a little more relaxed about it and is comfortable with grazing early in the season.
“I regard this as a minimum cost operation with immediate payback, so am not fussed about getting the maximum possible success rate as it’s just another tool in the system,” he said.
Colin’s biggest concern, once the seed has germinated, is shading from other ryegrass plants and broadleaf weeds, which he believes can be just as detrimental as an animal potentially pulling the plant out of the ground.
The other thing that Colin is conscious of with his light soils is the potential damage that black headed cockchafers can cause, so he monitors carefully and takes action early if grubs appear.
Other autumn issues that will impact negatively on the results are false breaks and excessive trash levels.
“Excessive trash can be guarded against, with solid grazing over summer and in early autumn, but false breaks are in the lap of the gods,” Colin said.
Despite this, results from original trial showed large volumes of seeds could be generated through recruitment.
Therefore, Colin hopes not all seed will germinate with the first rain, so there may be a second germination with later rain events.
Colin said even if seedling recruitment wasn’t successful in one season, he’d repeat the process again the following year.
“It’s a very low risk option and I’m not compromising animal production by doing this when there’s already grass everywhere in November and December,” he said.
So far, repeat treatment has not been something that he has had to employ, with the single year treatment delivering significant benefits each time.
The results of the original trial showed that the percentage of perennial ryegrass in the pasture the following spring was more than double that of the untreated control paddock.