The Making Good Better project recently held the first workshop for our 15 focus farmers at Rob and Jo Bradley's property Woollen Park. The topic for the day was sustainable rotations and green manures. We started the day with an excellent overview by Rob of his Nuffield Scholarship, which looked at the sustainability of mixed farming systems. Rob's key concern is that in our cropping systems inputs and efforts are on an upwards trend to keep producing the same yields - not sustainable from any measure. As he travelled the world, Rob found that integrated livestock and cropping systems (like ours in Tassie) are actually quite rare and "old fashioned”. Instead, the trend of overseas commercial farms is increasingly to separate livestock and cropping as the system intensifies. He ventured into the organic sphere where integration is still practised and an important part of the nutrient cycle. An organic cropping/dairy farm which he visited relies on clover pastures for nitrogen inputs - the farmer had been conventional and converted to organics for economic reasons and said his key learning had been that he would never use nitrogen fertilisers again! While the long term productivity of this brave move is unknown, it does demonstrate this farmer's faith in the benefit of green manure crops.
Sam Rees (our in house soil boffin) plugged the details from Rob's cropping rotations into a TIAR soil carbon model - Black Magic. Based on the starting soil carbon level and the cropping rotation used (including stubble management), the model predicts the trend and final value of soil carbon after a defined number of years. We looked at some interesting scenarios and found that fallowing ground has the single biggest impact on soil carbon levels. It was also pretty clear that pastures contribute a huge amount of carbon to the soil system.
Finally Pete Aird from Serve-Ag went through some trial data and information prepared by Jason Lynch on his recent travels overseas, reviewing green manure crops and biofumigants. Both are used as a matter of course overseas. The key to using them successfully is planning properly - work backwards from your next crop and when you want to sow it. This will give the number of weeks your cover crop will have in the ground, which will be a key consideration in what will be most suitable (e.g. clovers are slow to get going while oats are very quick). Other things to consider are the amount of material left at the end of the cover crop and how you will handle this (e.g. spray, cultivate, etc) so you don't compromise planting your next commercial crop. Whether you want to graze your cover crop is another consideration.
The day wrapped up with a good look around the farm and at what Rob's been doing - drainage was a key factor on many of the soils he is farming, and it is critical to get this right to maximise your paddock's potential. Raised beds was one option used by Rob and he took us to see a paddock which had been dryland poppies last year and was then sown to wheat (with the beds left in place). All looked good, despite the recent wet! The tour moved on to see a strong contrast between a paddock where broccoli had been grown last year and its mate, which had grown grass. Broccoli is a late crop and this paddock had been grazed before the stubble was ploughed back in. There was a clear difference in structure between the two areas, with the grass paddock looking better structured.
We finished off with a look at the dairy and at what soils look like under the dairy pastures - answer fantastic!
All in all a really informative day and the group were very grateful to Rob for sharing his thoughts with us.
Sam Rees (our in house soil boffin) plugged the details from Rob's cropping rotations into a TIAR soil carbon model - Black Magic. Based on the starting soil carbon level and the cropping rotation used (including stubble management), the model predicts the trend and final value of soil carbon after a defined number of years. We looked at some interesting scenarios and found that fallowing ground has the single biggest impact on soil carbon levels. It was also pretty clear that pastures contribute a huge amount of carbon to the soil system.
Finally Pete Aird from Serve-Ag went through some trial data and information prepared by Jason Lynch on his recent travels overseas, reviewing green manure crops and biofumigants. Both are used as a matter of course overseas. The key to using them successfully is planning properly - work backwards from your next crop and when you want to sow it. This will give the number of weeks your cover crop will have in the ground, which will be a key consideration in what will be most suitable (e.g. clovers are slow to get going while oats are very quick). Other things to consider are the amount of material left at the end of the cover crop and how you will handle this (e.g. spray, cultivate, etc) so you don't compromise planting your next commercial crop. Whether you want to graze your cover crop is another consideration.
The day wrapped up with a good look around the farm and at what Rob's been doing - drainage was a key factor on many of the soils he is farming, and it is critical to get this right to maximise your paddock's potential. Raised beds was one option used by Rob and he took us to see a paddock which had been dryland poppies last year and was then sown to wheat (with the beds left in place). All looked good, despite the recent wet! The tour moved on to see a strong contrast between a paddock where broccoli had been grown last year and its mate, which had grown grass. Broccoli is a late crop and this paddock had been grazed before the stubble was ploughed back in. There was a clear difference in structure between the two areas, with the grass paddock looking better structured.
We finished off with a look at the dairy and at what soils look like under the dairy pastures - answer fantastic!
All in all a really informative day and the group were very grateful to Rob for sharing his thoughts with us.
