DROUGHT IS A CHOICE. WE HAVE DROUGHT BECAUSE WE DON’T KEEP THE RAIN WE GET
If you get 10 inches of rain per year, but only 4 inches soaks into the ground, did you get 10 inches of rain? Or only 4 inches?
A conversation with Alejandro Carrillo, who has made his Mexican cattle ranch largely drought-proof, by restoring the soil, the plant matter and the water cycles … using cattle.
“We can go for nine to ten months with no rain, and our grasses are still going to be green because the microaggregates (in the soil) store the water.”
--Alejandro Carrillo
HART HAGAN: You're saying that, when you fix the water cycle, a lot of other things happen because all living things need water. Animals need water. Plants need water. Fungi need water. Microbes need water. So you're saying that you are able to fix the water cycle. And then when you fix the water cycle, then other things follow naturally from that. So how do you fix the water cycle?
ALEJANDRO CARRILLO: Let's consider the insects, like the dung beetles and the termites. The cows are great, but if we don't have the insects to finish what the cows started, like working the cow pie and putting that cow pie into the soil--and then letting the termites finish it--then we’re just doing half the job. But in order for those insects to work, we need to fix the water cycle.
And now you ask, Hart, how about the water cycle? Well, first of all, we need to be able to infiltrate more water. In the state of Chihuahua, Mexico, we did a study statewide and found we are only infiltrating between 25% and 40% of the water.
Think about it. If I'm telling you that on my ranch, I get ten inches, really I'm only getting four inches. That’s why we are in this ongoing drought. So the first thing is to open the soil to get air in the soil, get that soil porosity.
The way it works is we need to extend the growing season with proper management. In the Chihuahuan desert nowadays, we only get rain for three months. Before we started this--when we were conventional ranchers--we only had green for three months, that's it.
And what is the problem of not having green year-round? The microbiology and specifically the mycorrhizal fungi--the one that helps us create soil aggregates which in turn helped us create this air in the soil, which will help us get more water--the microbiology and the mycorrhizal fungi need to be fed the whole year round.
So, if we don't have something green like healthy perennial grasses that are going to be green year-round, cool and warm season grasses, then we will not be feeding the microbiology which in turn will not create the aggregates in the soil.
So the first thing is improved “effective rainfall”--the amount of rainfall that soaks in, or infiltrates into the ground.
Then once you've got that water in the soil, the plants are going to take it and evapotranspirate. Not evaporation, evapotranspiration. And then you start seeing the water cycle working.
HART HAGAN: So you're saying that you are able to increase your infiltration rates by restoring the soil, restoring the soil porosity, so that when it does rain, if you get 10 inches of rain per year, then you're getting all 10 inches, as opposed to getting 10 inches of rain, but only 40% of it soaks into the ground, so you’re just getting four inches of rain per year soaking in.
ALEJANDRO CARRILLO: What we need in most ranches and rangeland is biology. We don't need chemical stuff. We need biology. The cow is the one bringing the biology, by breaking the hardpan with their hooves, by cutting the grass, by the saliva effect, by putting the manure full of microbes and then the insects taking that cow pie and putting it into the soil, feeding the microbiology.
Pretty much our whole work is, how can we feed the microbiology? The livestock is the one feeding the microbiology. And then strengthen the grasses. The grasses are going to be the ones that are going to be putting these exudates into the microbiology.
HART HAGAN: So you're saying that, what the land needs is biology. And the cows, for example, bring the biology. They have hoof impact, which breaks the hard pan. They have manure and urine which provides the biology. The biology in their gut gets pooped out and peed out, and it lends its biology to the soil.
So then the soil has biology. And somehow, that biology increases your infiltration rates and increases the ability of the rain to get absorbed into the ground and stay there and lengthen your growing season, your green season.
ALEJANDRO CARRILLO: Yes, Hart, and we need to remember that there's a symbiosis. Microbiology depends on the grasses. And the grasses depend on the microbiology. And the microbiology, such as mycorrhizal fungi, stores water where the grasses can use it when it doesn’t rain.
That's why we can go for nine to ten months with no rain, and our grasses are still going to be green because the microaggregates are going to store water.
Think about it, Hart. What happens in sand dunes, in sandy soil? Well, the microbiology stores the water. It doesn't let the water get all the way down. It stores the water where the plant can use it.
HART HAGAN: So your soil soaks in the rain because it has the biology that it takes to give the soil structure. About half of good soil is porous. Those pore spaces contain either air or water. So even when it hasn't rained for a long time, the plants have water available to them. And they have biology available to them as well. And that's possible, you're saying because of the animal impact.
ALEJANDRO CARRILLO: Yes. I mean really, Hart, it doesn't matter how much rain you get. I get only 10 inches, but we've been in places in the tropics where they get 200 inches. And the root system is very shallow even when you get 200 inches.
I mean it's completely unrelated to how much water you get. It is how much water you can infiltrate. It’s how porous your soil is. The moisture could be way down below, but the root system will go only as far as it can find water and air.
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Food for thought: Imagine how much less drought we would have in the deserts of the world if land managers would manage livestock with methods similar to those used by Alejandro Carrillo, who has turned his own ranch from a desert to a grassland in ten years.
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