Ever since I went to the Friends of Grasslands workshop in 2014 I’ve been itching to try my hand at revegetating native grasses, rather than only trees and shrubs.
Of course, that’s not all that easy to do. Sue McIntyre has some good suggestions, but we are mostly forced to deal with weeds where we can, and hope that native grasses and forbs can do all right on their own.
On both farms, my parents made a big effort to “improve” the pasture with introduced grasses such as phalaris, clovers, and lucerne, which increase the carrying capacity for sheep (you hope), but need fertilizer and water to survive. During the “Millenium Drought” from 2001-2008, it was the native grasses that kept at least some coverage on the bare hills because of their ability to withstand lack of water.
I thought that there was some affinity between native grasses and rocks in particular, because that’s where I saw most of the remnant forbs and wildflowers. That was, until we had a visit from someone who’d worked at Esdale in 1970-71 and was very proud of having ripped all the hills he could with a tractor on a dangerous tilt and enthusiastically sowed introduced pastures. The area we fenced for a Box-Gum woodland reserve was one of the ones that was just too steep to plough.
I think the survival of native grasses has been highest on the back hills also partly because the water supply was limited in the hot seasons, so it was less often grazed in high summer when the native grasses are seeding. I’ve been working on making it possible to do more rotational grazing by improving the water supplies (digging a waterhole, adding troughs), but that may mean more summer grazing and less native grass. Just locking the gate against sheep isn’t a great option though, because the land can be quickly overrun with wild oats, saffron thistles and other weeds. It’s all a balancing act.
In the meantime, I had an opportunity to create a new area of native grasses on Adnamira when I had an old dump area covered up and levelled to provide access to one of our revegetation areas. The dump was a hazard, full of barbed wire, old kitchen cabinets as well as car tyres that had been thrown around in an attempt to control the soil erosion. Some of the tyres were loose enough to have washed all the way down into the neighbour’s dam at Carkella, and then were thrown back over the fence. Tyres in particular are better buried than sitting above ground leaching unpleasant compounds into the water so this pile isn’t great.
Anyway, I got an offer for a few truck loads of clean soil (called “VENM” which confused me for a while, thinking they meant some sort of poison rather than “Virgin Excavated Natural Material”). Frank had dealt with the supplier before, so he advised “Make sure you get topsoil, and get it first, or you’ll have trouble”. I made that condition with the supplier, plus his promise to use the bulldozer to clear out and reform the shallow dam in the same paddock.
So the trucks started arriving in March 2015, and the old rubbish was soon buried. I’d paced out the area and calculated it would be around 50 by 30 metres and ordered a supply of native grass seeds from Greening Australia to cover that. These seeds included kangaroo grass, wheatgrass, 2 types of speargrass (austrostipa), windmill grass, weeping grass, and red anther wallaby grass. The nearby rocky ridge had a lot of weedy thistles, but also some remnant speargrasses and redleg grass that I hoped would help fill out the area. The mice promptly got into one of the bags when I stored them in the laundry.
One of my reasons for wanting to sow the area rather than just let it re-seed was to speed up the ground-covering and keep out weeds. An area where silt had been dug out of a dam on Esdale in 2013 had been left to grass up by itself, and produced an impressive array of prickly Bathurst Burr.
Greening Australia’s instructions for sowing the seeds included:
- raking the topsoil in the area to be sown, to allow seeds to settle in.
- mixing the seeds in buckets with a larger quantity of sand to help break up the clumps and disentangle the long awns.
- covering the sown area with straw or hay for protection
- ideally, rain before and after sowing would make it more successful.
After some delays I had nagged the VENM delivery guys to spread the topsoil, organized my team of 3 CIT student assistants for the day and headed over to Adnamira, by then in May 2015. There I found that most of the newly spread topsoil had been covered by new subsoil and there was nothing to plant into but tumbled clay. I angrily called the contractor, and he put the blame on his “stupid” drivers, and promised more topsoil.
Which didn’t come. But more loads of unwanted subsoil kept arriving, filling more of the gully and making a much bigger area than I’d planned on. More promises of topsoil, but only three miserable piles. I had got a little over-excited by the idea of having a big, level, non-rocky paddock so I let it go on for longer than I should have. In addition, strategic dollops of rain meant the dam couldn’t be emptied and dug out, so that benefit was not happening. At least the contractor’s supposedly “stupid” drivers were doing a good job of compacting the soil and banking it so that it didn’t wash out, but I was concerned that the only way to stop it eroding in the long term was to get it planted.
Eventually Craig and I gave up waiting and planted the small area immediately below the dam that was properly prepared, using about a quarter of the seeds. By then (November 2015) I was beginning to worry that the expensive seeds would be so old they wouldn’t be viable.
Frank had supplied us with a bale of water-damaged hay which we spread on the new seeds. Unfortunately the sheep in the paddock promptly ate the some of hay and the rest blew away. The area did begin to grass up, though, and there were almost no weeds.
Down the gully, the earthworks continued right down to where it joined another gully and made a new small dam. At this point a halt was called. The council complained that I was filling waterlines with dirt, and banned any further dumping, so there never was going to be topsoil for the now triple-sized area. A big problem.
Finally I developed a plan. I’d learned from Greening Australia that they often pushed off existing topsoil to plant native grasses, to reduce the fertility and get rid of unwanted weed seeds. So I stopped panicking about having no topsoil and bought some additional expensive seed. I arranged with the amazing James O’Keefe to get ten truckloads of used hay from a horse show delivered. That would make the mulch layer to start creating new topsoil. It would also provide some seed from the hay for some pasture grasses in the outsized planting area. And we could sow directly into the hay.
Worried about the viability of the older seed, I started some seeds in tubes which seemed to grow well, but mainly with wheatgrass as far as I could tell. I added some fresh windmill grass seed to my sacks. This I’d collected from around the house. Finally in September 2016 Craig, Matthew Kent and I headed out and started the main planting.Craig was in charge of spreading the giant piles of hay with the Bobkitten, while Matt and I raked it more evenly and sowed. The hay was heavy with horse manure, but this was an advantage because the cattle in the paddock weren’t interested in eating it, and it didn’t blow away. We found quite a bit of horsey-people rubbish – blue disposable gloves, a tube of drench, blue paper cloths stained with hoof polish, and a fair number of candy wrappers. Overall it wasn’t too bad, though, out of the ten truckloads only two big buckets of rubbish. The raking was heavy work and took a lot longer than I’d imagined. I think I was expecting to merely whisk it about and be done, but it went on and on.
Matt did most of the mixing up of the seed with the sand and dragging buckets, even keeping a smile on his face. We did our best to leave areas that had good grass volunteering already, as “windows” in the hay.
The tubestock we planted along the edges. Steve Donellan from Adelaide, experienced with roadside native grass planting, told me to put them close together in tufts, rather than scattered about. Apparently they do much better that way. Unfortunately, not all of them got planted as I lost track of the crowbar, but those that were survived.
At the lower end, the steepness was allowing the beginnings of some erosion. We filled the small channels with hay, leveling the ground with a mattock where we could. My plan is to add a truckload of rocks, with the help of James O’Keefe, to armor the second gully against washing out, but that part of the project hasn’t happened yet.
By spring in November 2016 the whole area was showing a scattering of grass cover despite the sheep still grazing there, and the hay was still doing its job of providing a soft fall for the rain and seeds.
Checking in the autumn (April), I found good grass cover in the first area Craig and I seeded,and reasonable grass cover, with little sign of new washouts in the larger, lower section.
The hay may have been too thick in some places, suppressing the grass growth, in others too thin. The best grass coverage is definitely where the topsoil was placed. In the most established top section there is a lot of windmill grass, speargrass, and wahlenbergia flowers which I’m assuming came in from nearby.
Overall this has been a long and frustrating project. At least I’m not alone in that, as it turns out that the DPI Article “Grassed Up” (well worth reading if you’re interested) mentions the “notable lack of establishment success from many preliminary plantings (of native grasses)”. On the other hand, I’ve seen lovely results from spreading hay on sheet erosion areas as Margie Fitzpatrick’s “Australind” (no seeding). I think we’ve done okay, but I’d have to think carefully before trying something similar elsewhere. Mostly I’ll continue to try and improve the general conditions for native grasses by planting shrubs and trees as overstoreys elsewhere.
The results will I think be good in the long run. We definitely have fewer weeds and a bigger variety of native grasses than we would have if we’d just left it to itself, and especially in comparison to an area which was compressed by the trucks but we didn’t seed or spread hay.
But I’ll never trust a dirt dumping contractor again.