Surpassing my wildest dreams in sustainability

You can’t wipe the grin off my face at the moment because one of my most daring experiments has reaped massive dividends: a tripling of our topsoil in three years.

Three years ago, almost half of our pastures were destroyed by the root-eating red-headed cockchafer.

Red headed cockchafer grubs

Red-headed cockchafer grubs

These rotten grubs turned paddock 4 into a fluffy mix of topsoil and the desiccated remains of our ryegrass just ahead of Spring. It was devastating. You can’t control them with sprays because they stay too far down in the soil to be affected. The only alternatives are to resow and hope they won’t come back or physically squash them with cultivation and then resow and hope they don’t come back. The experts said two cockchafers per shovelful of soil equated to an infestation and paddock 4 had up to 50.

I became desperately worried as more and more paddocks succumbed. I started digging holes all over the farm trying to work out what would be hit next and looking for a cause in the hope of finding a solution. I failed in that quest but the exercise was worthwhile because the grubs taught me an incredibly valuable lesson. The pastures that suffered the most had relatively shallow topsoils over a hard clay pan.

Paddock 4 had about 12 to 15 cm of sandy loam over the moderately sodic clay. I decided to turn the expense of recultivation into an investment and had the soils deep-ripped and dressed with soil-conditioning gypsum in an attempt to keep them open.

Paddock 4 was sown with oats because they provide quick feed to fill the gap created by the grubs and their long roots are relatively cockchafer-resistant. After the oats were taken off in late spring, we planted the paddock with a summer brassica crop, which again has deep roots.

It was clearly time for some very expert help and we engaged independent agronomist Greg Forster, who worked out the nutrients, trace elements and lime needed to allow the soil to function at its best. We have since ploughed in the remains of a brassica crop, too.

Then, this week, scientists arrived to take metre-deep cores for analysis as part of the Victorian Soil Carbon Project. I was stunned. Too stunned even to remember to take a photo but that 12cm topsoil was now more like 45cm deep. “Lots of farmers would give their right arms to have soil like that,” remarked the supervisor.

I can’t believe it. I’m blown away and ever so slightly grateful to the red-headed cockchafer (though don’t think that’s an invitation to come back, you nasty little blighters).

False messiahs of the soil

Oats planted into a deep-ripped paddock

Oats planted into a deep-ripped paddock keep the soil open

There are plenty of people out there at the moment promising farmers an organic/biodynamic/permaculture nirvana. “Use less fertiliser, restore soils, improve animal health and fertility,” they cry. That’s a very attractive set of propositions to a dairy farmer like me and I have been tinkering around the edges, listening, sifting and learning.

Although alternative farming practices have been around for centuries, they’ve never been commercialised and marketed to the mainstream in the way they are today. In my experience, with that marketing has come some very questionable “experts”. I guess it’s like any emerging school of thought – there will be a mix of true visionaries, snake oil salesmen, good practitioners and fools. The trick is to work out who’s who!

Yet it seems almost every proponent of these alternative farming movements does have something to offer. Composting, for example, is a great way to improve the biological health and structure of our soils and this seems to be a universal tenet of all the alternative farming philosophies. It also resonates with me as a gardener. If I could afford to, I would “garden” the entire 500 acres but the intensive treatment we give our veggie plots is not feasible on such a large scale. Whatever we do has to be manageable.

I was all set to do an 11 hectare composting trial this year until a set of logistical nightmares stopped me in my tracks. The plan was to deep rip the soil, add lime and then hay soaked with effluent on one half of the paddock, while using more conventional treatments on the other half. I am almost certain it would have been a great success, so will have another go next season.

I think it will work best on our most troublesome soils. Some parts of the farm have a layer of compacted soil or “hard pan” caused by an acidic reaction, which prevents water from penetrating deeply. This means that those paddocks get very wet soon after rain but dry out extremely quickly. I’m aiming to break down that layer to increase the plant available water capacity of the soil. Paddocks of this type that are due for renovation have been deep ripped, limed and planted to oats, which have long, quick-growing roots. In the last couple of seasons, I’ve found that deep-ripped paddocks planted to long-rooted plants like brassicas and oats have remained more permeable than those planted immediately to rye grass.

I’ll keep on learning more about alternative farming techniques (with ears and eyes open) and gradually trial them on farm.