Sub-soiling: capturing the rain

The pictures say it all! These pictures were taken in 2012. We were in the middle of the worst drought on record for Medina County, Texas. In 2011 we recorded about 6 inches of rain on the ranch and about 8 inches in 2012. The first picture is me and my good friend and former intern Chris Niels sitting on the tractor in spring of 2012. We pulled a single shank Bison sub-soiler with my grandfathers old Ford 5000 tractor. This pasture is located near our home on top of the hill and is unrecognizable today if compared to this picture. The soil was so hard and compact that we had to weigh the sub-soiler with tractor wheel weights and fill the tractor tires with water. We ripped do a depth of about 29 inches. The picture to the right is in the fall of 2012. It didn’t rain all summer and we had a few small rains totaling only a few inches by early fall. Look at where the grass grew! Today that pasture has virtually no bare ground and is predominantly perennial grasses. This initial experiment years ago made me a believer.

You first need to understand a few things about our soil. To put things into perspective we are in a heavy clay loam. When it rains and there is no vegetation cover the soil moistens at the top, the wet clay expands and the water simply “sheds” off. The water is not captured where it falls and instead makes its way rapidly to the creek and before you know it ends up in the Gulf of Mexico. Sub-soiling rips open the soil so that when rainfall events do occur it captures that water and allows it to infiltrate deep into the soil. One of our biggest problems when we first start sub-soiling years ago is that we no longer had the runoff during large rainfall events to fill up our stock tanks and the deeper water holes in the creek. What has started to happen is the water is moving below the surface and our creek has been running for almost a solid year now. Sub-soiling also offers another major benefit, aeration. By allowing the soil to “breathe” we are creating habitat for soil life and conditions for plants to thrive.

We now pull a double shank sub-soiler with our John Deere 4055. Still ripping to a depth of about 29 inches. We can cover a lot more ground in less time. We are still sub-soiling pastures every other year or so and continuing to see amazing results. We are currently conducting research with SARE (Sustainable Agriculture Research & Education) and Texas A&M AgriLife Extension Service on the long-term effects of sub-soiling. I will write a blog specifically about that research in the weeks to come.

The idea of sub-soiling came to me from the writings of PA Yeoman of Australia. He wrote several intriguing books on water and land management including: Water for Every Farm, Yeomans Keyline Plan. He was a visionary land manager that pioneered the idea of sub-soiling pastures to improve water infiltration. We don’t exactly his techniques verbatim, but there are a lot of parallels.

Disclaimer: We DO NOT recommend sub-soiling for every type of soil. It’s all about context folks.