Resources for retaining water on hilltops

[Lee Rinehart]

I received a question during the Soil for Water Film Premiere with Panel Discussion on February 17, and I wanted to share some resources based on the question. IB wrote, “are there any tips or resources you can give us for those who are on hilltops for retaining water?

If you are growing crops, permaculture can be a great way to retain water on hilltops. Techniques you could think about include planting deep rooted perennials as a basis for the garden/crop production, creating swales, berms, and terraces, using Hugelkultur or mound culture, and rainwater harvesting. A good source of information is Permaculture Design Notes from the Permaculture Institute. See also the industry standard Permaculture A Designers Manual by Bill Mollison.

For hilltop pastures, maintaining a dense sward of diverse grasses and forbs is the best way to ensure water retention. The ATTRA publication Building Healthy Pasture Soils goes into detail on practices to build aggregation and good soil structure, which allows soil to act like a sponge instead of a brick. Also, there are certain engineering practices you can do to prevent or control runoff, and the NRCS has practice standards that can provide technical and financial assistance to install practices like livestock walkways, contour farming, dams and diversions, hillside ditches, and terraces. Start by contacting an NRCS Conservationist at one of the USDA Service Centers.

 

[Omar Rodriguez]

Hi Lee, those are some great resources, thank you. I wonder if anyone at NCAT has experience with Keyline design. In terms of getting water to infiltrate and migrate toward the ridges, I have heard that this can be an effective practice.

 

[Lee Rinehart]

Hi Omar I have no experience but I will be following this to learn more.

 

[JustinM]

Hello Omar. A couple of years ago I took Mark Shepard's course in Keyline design while attending an Acres conference. Mark published a book on this subject and I have it, but I don't consider myself to be the authority. For that I'd recommend reaching out to Mark himself. He's located in Viola, Wisconsin. Mark's company is New Forest Farm and his contact information is on his website: https://newforestfarm.us/. Let us know what you find out .

 

[HernanC]

@Lee Rinehart, if on a hilltop, do you have any recommendations for watering frequency and duration? In deep South Texas, our usual practice is to water less frequently and for longer periods. Yet, at the NCAT demo farm, SIFT, the practice is quite the opposite (more frequent watering for shorter durations), and they've had great success!
So I'm wondering if irrigating on a hilltop changes any of that.

Check out the SIFT watering practices here under operations, irrigation https://attra.ncat.org/htmlpub/sift-2020-local-food/#operations
and a recent podcast with their farm manager https://attra.ncat.org/episode-253-how-to-conserve-water-at-an-urban-mountain-desert-farm/

 

[Lee Rinehart]

@HernanC, I think that whether you water frequently or less frequently the main goal is deep watering. This depends a lot on soil quality of course, namely creating a soil sponge through the 5 Soil Principles. On hillsides, especially on a steep slope, less frequently may be an option to prevent gravity from taking the water away upon application. Again, a quality soil can bind water in it's pore space but too much too fast may run off. My recommendation would be subsoil irrigation to help with root zone application. Some good sources of irrigation equipment are:

Eco-Drip
Drip Depot
Netafim
Irrigation Mart
Drip Works

 

[Nina Prater NCAT]

After Dale Strickler's presentation, I was thinking about how to increase water retention in our hilltop pasture soil. We do adaptive management grazing, and roll out round bales in the winter. We've been steadily increasing our SOM over the past 12 years. The thing I'm wondering about is that the soil itself is pretty shallow in spots, very close to bedrock. Like, 1 foot in places. That seems pretty limiting in terms of how much water we can hold! I wonder what cheap, easy, impactful actions we can take in these conditions. We've been talking about trying bale grazing in the winter this year as an experiment. But I wonder if anyone has other ideas for hilltop pasture with thin Ozark soil?

 

[Lee Rinehart]

One idea I have come across is tip grazing... running the stock through to graze the tops and move them off. By keeping alot of standing vegetation for cover this might help maintain cover and water holding on thin soils. I'm still looking into various ways to use Dale Strickler's ideas of water dispersion especially on hilltops and sides. The bale grazing I believe is a good idea, or even stockpiling this pasture and using it in winter.

 

[teddy569]

interesting information

 

[JustinM]

While living and working in the driftless region of Wisconsin a few years back I was invited by a landowner to look at what was limiting his pasture's forage productivity on his hilltop. After doing a fair bit of digging with a shovel I found that most of his A horizon (topsoil) had eroded off and likely ended up downhill, maybe even to the Gulf of Mexico. What was left was what appeared to be mostly subsoil until hitting bedrock 18 inches down. The soil was very compact which could be detected with a knife or wire flag. Plant roots were very shallow (mostly less than 3-inches). My suggestion to him at the time was to allow plants to get taller and more recovered (late elongation/early reproductive phase) before turning the critters in. And then once the critters are in, getting them out once he reached an average stubble height of 6 inches. The key to increasing plant available water in soil is by maximizing root exudation. It's through the root exudation process that soil life like bacteria and mycorrhizal fungi are fed. Bacteria and fungi create the glues that enable the soil to aggregate. Soil aggregation allows more space in the soil to hold air and water. Good soil aggregation is absolutely necessary to improve plant available water no matter what landscape position or soil one might have.

Something else that might improve water retention on hilltop pastures as well as pastures anywhere else could be through the application of biochar in the mineral supplement of livestock. This won't be a quick improvement but will take some time. Feeding biochar through livestock and letting the livestock spread it would be much lower cost than mechanically spreading it. Dale Strickler talks about this in his book, The Drought Resilient Farm, pages 62 - 64.