A few days ago I drove up to Booneville, Missouri, to hear Gabe Brown and David Brandt prove soil health and profits are improved using multi-species cover crops and mob grazing on crop ground.
Gabe Brown and his family were arguably the founders of the no-till, multi-species cover-cropping movement which is now spreading well beyond their home in North Dakota. I went to see Brown clear back in 2008 and the data he had amassed at that time with the help of local NRCS and a young USDA-ARS soil scientist was impressive. It is even better now.
Dave Brandt is a no-till farmer from Ohio who, well before Gabe Brown started experimenting with no-till and cover crops in the early 1990s, was using cover crops in between his cash crops.
Both men offered some very interesting data to back up their many years of practical proof.
Doug Peterson, Missouri NRCS's state soil health specialist, helped set up three workshops with these innovators. Peterson says both men have great stories to tell and Brown's work with mob-grazing cattle on his family's farm ground seems to be jumpstarting soil health even faster than the multi-species cover crops.
I'll get into all this more in the June issue of Beef Producer but a couple things really jumped out at me when I heard the two men make their presentations.
First was the point I already mentioned about livestock, properly grazed, adding to the productivity of the system.
Second was a data set Brandt had from his farms showing multiple-species cover crops didn't use any more soil moisture than having no cover crop at all.
Brown's slide of his data on livestock grazing wasn't altogether conclusive because it actually compared a very limited species composition left ungrazed to a multi-species, no-till farm ground which was grazed.
The ground with multi-species cover crops and ultra-high-density grazing by livestock had more stored nitrogen, phosphorus, potassium and stored carbon.
Brown says they have additional supporting data from the research farm near Bismarck. I plan to get that from him.
However, in the course of this discussion Brown said a very wise thing and something I noticed years ago but I find is still poorly understood.
He said, "Remember, compaction is a function of time. All biology in the soil has to live in the film of water on soil surfaces. So to have biologically active soil you must have pore space."
This is one key explanation why season-long grazing, or even long graze periods, is bad for all land, including crop land.
The nine-species cover crop left the most moisture in the field at 2, 6 and 10 inches depth, but the results were mixed among the other cover crop mixtures. Two of these had eight species and one had six species. This is only one year of data but some of the variation on soil moisture measurements may have as much to do with the interaction of the various species.
However, it's particularly worth noting the cover crop mixtures with the greatest complexity generally produced the highest corn yields, in addition to producing the highest biomass as cover crops. That is worth noting for graziers.
The most complex mixture also had the highest remaining nutrient value per acre after harvest of the corn crop.
Want to know more? Download a free Farm Progress report on cover crops here.