Who doesn’t want to fly two sides of a triangle to get to the right place? It’s even better when there’s a nice drive in the dark, rain and traffic at the other end. Still, we only nearly died once. This morning all the clouds had gone and it was a short drive to Fazenda Boa Vista. Lucio Damalla is one of the pioneers of no-till around here, he started doing it 39 years ago and is now heavily involved in all of their industry associations. In the afternoon I visited the local Embrapa centre, and met a couple of guys who are working on livestock integration.
Both visits had the same message, which was that having grass and animals in a rotation is going to be better for your soils, and give higher crop yields. The Embrapa guys had done the most work on systems which are 50% pasture (2 years pasture, 2 years crop). I don’t think there is much doubt that this is going to be a more efficient way of farming, the question really then just comes down to economics: can the livestock phase make enough money to be economically viable? I don’t think it can in the UK, not in the good arable areas anyway.
Lucio is more of a crop farmer than a cowboy. He does not breed any cattle, he just buys them in at certain times of year to do some grazing. There are no permanent pastures here, he just uses the Santa Fe system, as discussed on Day 65. Quick refresher – that’s when Brachiaria is planted at the same time as maize in the second crop slot. After harvest, the grass is ready to go, and can be grazed during the winter.
This idea is pretty similar in principle to how we use cover crops, so it’s interesting to see it in action. The benefits are the same as in the 50% pasture system, but just not as pronounced. Lucio has increased SOM from 2-3% in the 10 years that he’s been doing it, which compares to levels of around 4% in the trial rotations with permanent pastures. They both see significant yield increases in following cash crops, due to both the increased SOM, and also the changed physical soil properties. The grass roots open up the soil profile, allowing the cash crop roots to go down further, whilst also improving water infiltration. Although the rainfall here is ~2,000mm, they still suffer from small droughts in the summer, and it’s in these periods that the crops after grass show their real advantage.
I’ve long had the debate in my mind and with other people about whether it’s best to graze cover crops or not. It seems obvious that by grazing you’re going to lose some carbon (meat & methane), but is it a significant amount? The researchers at Embrapa are certain that it’s better to graze. They say you will get a measurably better crop afterwards (I think most would acknowledge this anyway), but also that it’s better for the long term soil fertility as well. The theory is that soil biology is stimulated by what comes out of the animal (both ends), and they also share Kris Nichols’ opinion that the physical act of grazing a plant causes some (as yet unquantified) beneficial soil effect, maybe by releasing a burst of root exudates. So far so good, that’s basically what I believe. I was really hoping though that thy would have some data on this particular situation, but it seems to be more of a hunch.
As an aside, one of the Embrapa guys, Julio Cesar, had the usual researchers’ habit of answering questions with “it depends”. I teased him a bit about it, and said he was fully qualified to come and work as a scientist in the UK because he wouldn’t give a straight answer or opinion. But it then occurred to me afterwards that when he did say what he thought (grazing cover crops is better), I said I needed to see the data. Maybe they just can’t win?