We’ve been planting grass this weekend. It seems a strange thing to do in a season that’s been plentiful with the green stuff. That may have been why I got eight trays of mixed native grasses going cheap.
On the other hand, I know that the top of the ridge in our Box-Gum woodland area was grazed pretty bare last year, and the thick grass that’s there now is (I think) mostly barley grass and could do with some more biodiversity. Well, it could be desirable microlaena (weeping grass) for all I know.
Last Thursday I went to a Murrumbateman Landcare talk by Dr Josh Dorrough about grass, grazing and what sorts of decisions can improve native biodiversity on land like ours.
He started out by hitting us with the bad news, that just changing grazing patterns doesn’t necessarily lead to a bigger variety of species of groundcover plants. And variety of species is the bottom line for trying to make the landscape more resilient.
Generally, the least effective tactic is taking away all grazing. That leads to less diversity, and increases in tall weeds such as wild oats and thistles. Overall there wasn’t much difference in the experiments he had done in Victoria and others elsewhere when trialling crash grazing, burning, infrequent grazing, spring destocking, etc.
But he went on to say that they’ve learned a lot from areas that have been protected, such as the travelling stock reserves, but in the end found it’s VERY HARD to increase diversity through changes in grazing management alone.
BUT you can improve 1/ ground cover 2/ soil protection and 3 shrub and tree growth and regeneration.
The stocking RATE (how many animals per hectare) is more important than broad rules on timing in increasing (or protecting) biodiversity.
JUDGEMENT is important too. Set stocking can be as effective as rotational grazing if the stock manager knows what they are doing. It’s a job requiring years of skill and judgement, and requires constant looking at the land, and re-assessing as you go along. For example, while spring grazing might in general knock back native plants that flower then, in a big wet year, the annual grasses could crowd them out if they’re not grazed. So ignoramuses like me need advice from people with skills.
To have biodiversity you also need to CONTROL WEEDS – the ones that love low fertility are the most tenacious and worrying, such as African Lovegrass. That’s because they like the same situation as Australian native grasses. African lovegrass comes in along the Murrumbidgee river banks when it floods and arrived only about ten years ago. We had a great time burning the thick dry tangles of grass in the winter of 2012, then working on poisoning the regrowth as well as grazing it hard where possible. There is certainly no longer a huge lovegrass monoculture along the river, but it’s a slow process and needs to be redone regularly.
The one part of the African lovegrass control process we haven’t done is sowing alternative groundcovers. It’s so problematic to sow in the river floodplain because the soil is so sandy and rocky. I’ve planted about a hundred trees down there and only about ten have survived the floods and droughts. Grass seed it seems to me would do even worse. Also, until now I haven’t had a good source of native grass seed.
Frank and Andrew also had thistles and other weeds like mallion weed sprayed on the ridges at Esdale. It was great watching the pilot swerving around the hills and then heading back up to Mountain Creek for more supplies. We delayed planting the new tubestock in the K2C grant area to avoid having them affected by the spray and they seem fine. It’s been effective on the weeds as the only thistles we see now are miserably unhealthy-looking.
The other way to get biodiversity is to ADD SEEDS AND PLANTS – we’ve been doing this with trees and shrubs, but I haven’t tried grass seeds. And I don’t have any.
However hearing Josh Dorrough’s talk did make me feel it would be worthwhile planting out the 350 mixed native grass seedlings I’d got hold of. The planting system we use is pretty basic. The plants had had a good soak before we brought them out. We used crowbars to slam holes in the ground and poked a seedling in each hole. We hope we get some rain to keep them alive.
I started with poking them just anywhere, which meant pretty much in the middle of existing grass clumps. That didn’t feel effective though, so we changed tack and made use of the areas where thistles had died off from the aerial spray they had in April, making bare patches. Searching them out seemed a better idea. A few were placed at the edged of the bigger spray areas we made for the trees we planted in that area.
In a year or so we’ll come back and compare the variety of grasses in that area with a comparable area further along the ridge. I’ll have to find someone who actually knows their grasses well.
The result so far look , hmm, similar to if we had done nothing. We’re learning by doing. Next I’d like to get hold of some of Josh’s seed from his site at naturalregen.com.au and give it a go.
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