In the above picture, you can see our McCain Foods pea crop planted into cultivated (Conventional treatment) soil on the left, and into sprayed our mixed cover crop (Hybrid treatment) in the centre. The golden patch is mixed cover crop residue in the Regenerative treatment plot that was mulched on 1 October. Some of the oats, tillage radish and other species remain alive under the mulch.
To completely terminate the cover prior to planting green beans in December, the Operations Advisory Group has decided to run disks over the plots to mix soil into the mulched residue to hasten its breakdown. They recommend spraying urea and a digester on to the residue first, to support the microbe population increase needed to chew through about 11 t/ha of biomass dry matter.
One of our big unknowns, is whether we can terminate the cover crops using a roller-crimper. Our literature and phone-calls-to-farmers research suggest timing is absolutely critical, and it is unlikely multiple species will be just right on the same day. We found for example, that the tillage radish was setting seed while the oats were not sufficiently mature for crushing. In our Regenerative treatment plots, we decided to mulch the five-species mix to avoid adding a gazillion radish seeds to our already well-stocked seed-bank.
We have also started termination programmes in the extra cover crops we planted. One crop is the same five-species mix as in the Carbon Positive Regenerative and Hybrid plots. Another is rye corn, one has straight tic beans, and one has tic beans and rye corn.
These crops were planted so we can try things without affecting the Carbon Positive plots. We started crushing strips with a roller-crimper on 10 October and will do more strips over the next few weeks. We are also considering mulching some and spraying any regrowth.
The images below show the bruised bars in the cover crops after roller-crimping. The theory is that once plants reach physiological maturity and flowering, they will not continue new vegetative growth if damaged. Bruising is thought better than cutting.
Thanks to TRS in Hastings for providing the tractor and crimper for these trials. We will be demonstrating it working at our Field Walk on Tuesday 15 October at the LandWISE MicroFarm. Everyone is welcome – but please register for free.
This work is being completed as part of the MPI Funded Carbon Positive project, a joint programme with the Hawke’s Bay Future Farming Trust. We a grateful for our industry sponsors and everyone who contributes through advisory groups, being tolerant contractors, and in many small ways!
