Grassland Soil Health: Infiltration


the management of South Dakota’s grazing lands is paramount to the healthy functioning of our soil and water resources sound management practices not only lead to economic but ecological sustainability while improper management reduces the resources capacity to function and can lead to the invasion of non-native species recently conservationists have been studying the effects that management has on soil properties such as infiltration and the results have been dramatic I’m Stan Boltz I’m the state range management specialist here in South Dakota with the USDA Natural Resources Conservation Service we’ve come out here today to to look at a difference between these different sites of grassland on the other side of the fence we have one of the common grazing systems that you see out here basically what we call a continuous season-long grazing what you have is a real uniform plant community blue grama Kentucky bluegrass not a whole lot of diversity as you can see on the on the west side of the fence here we have a very high diverse plant community very productive we’ve got big bluestem Western wheatgrass and a lot of Forbes coming in as well so the the diversity on the west side of the fence is much higher as well as the productivity and the vigor the health and vigor of the plants are much higher as well both sides of the fence will will grow beef so you can graze both sides and get production on beef however the sustainability on that side of the fence is not as high the productivity is lower and also the palatability you can see that with the diversity of species you’re going to have different things greening up at different times of the season and so that provides higher palatability throughout the growing season whereas on that side of the fence with the uniform plant community you get one shot when when things green up and then the palatability goes down so why you can grow well you can grow beef on that side of the fence you’re not going to do as well as you are on this side of the fence where you have higher diversity higher productivity and and by and large higher power throughout the season so that’s some of the things we see above ground as a result of grazing management you’re going to see changes below ground as well and one of the things that we look at is infiltration to kind of test and see what changes have occurred below ground in the soil so the first thing we want to do is clip off the grass so we’re looking right at the soil surface and water running on that instead of through a whole bunch of grass what we’re going to do is we’re going to drive an infiltration ring into the ground and then put some water into it and basically it amounts to one inch of water and we will time that so we can see how long it takes for the water to go in so we basically start with this ring here and drive it into the ground so what we do now is we basically just put a piece of saran wrap in the ring to hold the water up until we’re ready to start the timer and start the water run and then we have pre-measured 440 milliliters of water which in the six-inch ring equals 1 inch of water going into the ground pull that out that’s why i said you know start the timer and you don’t want to leave because it goes in pretty fast on this rangeland so that’s about it 10.1 seconds okay we’re going to take this ring out of the ground and take a look at what hope we see end of the ground after running that inch of water into it so after putting an inch of water in there you can see that the soil structure moisture came all the way down through here and it’s wet you can see the moisture here you can see that the great routes root structure coming down through here the soil structure is also very crumbly and very good quality soil structure but we’ll take a look at that the profile as well and see what it looks like so we can see the amount of litter and an organic matter right at the surface of the soil right away you can see the this granular structure throughout the surface of the soil and what that shows us is that we have tremendous soul aggregate stability in that soil and that’s really what allows that that in pore space allows that infiltration to go into the ground so well these saw aggregate aggregates here are held together by a protein called glomalin which is basically a byproduct of mycorrhizal fungi in the soil and that’s what helps to hold the soil particles together and create such great soil structure here we often see good granular structure on grassland soil across the state the better the management the deeper that is and the better than infiltration and the lower the runoff will be and so this is just a great example of that also you can see the tremendous roots going down through this profile and continuing on and so now we’re going to jump across the fancier look at the east side of the fence where we have a very low diversity plant community productivity is much lower and you will see as we look on that side of the fence that we’ve also the grassland over there has been converted to cropland and we’re going to look at the grassland part of it but we’re going to look at the same things on that side of the fence and see how those things changes we change management we’ve jumped across the fence here now we’re on the east side of the fence and we’re looking at a totally different plant composition here we’ve changed that composition quite a bit we have a sand drop seed blue grama there’s some Kentucky bluegrass in here and some crusted you can see the statue of the plants is decreased as well and often oftentimes what you see above the ground will be a reflection of what’s underground to as far as the wood struck sure goes so right now we’re just going to go ahead and clip the area and set the infiltration ring and we’re going to see how how fast the water infiltrates on this side of the fence alright so we’ve got that ring in about the right amount they’re going to add an inch of water to this soil profile and start the clock and see how long it takes to infiltrate that inch of water and some have said as much as a 150 to 200 pounds per acre of production will be lost with every inch of water that runs off the soil so this infiltration matters quite a bit in terms of how potent productive the rangeland will be and it ties into the bottom line the economics of an operation as well so we’ve had we’ve run through and we took seven minutes and three seconds to to get that inch of water into the soil profile quite a bit different from the more diverse range land the higher condition range land where it only took ten seconds to infiltrate that inch of water so let’s go ahead and take this ring out of the ground and see what this all looks like underneath it so I think you can see here really the most of this profile down here is still dry as compared to the other one we had water completely through the the surface the bottom surface of the ring we’ve got a little bit of water over here but you can also see that there really is very few pores in this subsoil here it looks like it’s an entirely filled with soil basically that doesn’t allow for the water to come through very well let’s see if we can push this out and look what so pry this apart and it looks like on the inside in comparison to the good condition range land we can we do still see some granular structure up here near the surface but we don’t see it going down all the way through the small profile we have right here another thing you can kind of see is right in here is this platy these layers of soil that are going more sideways than up and down there’s a good example right there the soil breaks part in the horizontal layers as opposed to the blocky structure we head down further or the granular structure that is due to some compaction going on that is mostly due to the long history of heavy livestock grazing that has caused that compaction below the surface there that contributes to poor infiltration as well and you can just see that that nice granular structure that we had all the way through the profile across the fence is just not there our aggregate stability has been lost as well and the structure the soil pads just kind of melt together into one big one big blob all these things contribute to poor infiltration and increased runoff and I as well you can tell that we don’t have the routing going down even below the ring hardly we have a few roots coming down below that level of the ring but most of the roots that are there are compacting the surface that can adds to reduced infiltration as well on the good condition range on the other side of the fence we had much better soil structure much pedaling much better infiltration we went from 10 seconds and on the good condition range to over here we had seven minutes that’s a tremendous difference every every minute that goes by is another inch of rain that’s going to run off the land and not come down into the soil profile in girl grass so what that basically boils down to is is more infiltration more production and that relates to longer-term economic and ecological sustainability right within this same field we have some in the same field we have some land that was recently converted to cropland the the grassland was sprayed out and the crop was planted right into that grass so we’re going to see what has happened in the last nine months since this got converted to cropland even though they didn’t till it will see what effect the cropping and the killing of the grass has they had on this soil right here so we’re going to go ahead and pound a ring into the ground and see what happens with our inch of water so we’re going to plot cellophane wrap in start the timer and see how long it takes for that inch of water to go into this recently converted cropland so we’ve let this run its course and our water has finally infiltrated looks like we end up with 31 minutes and 13 seconds that it took Ford to infiltrate on this recently converted cropland so we’ve completed our infiltration test here we’ve run samples ran an inch of water in all three of these conditions that we look back a good kid range condition on the west side of the fence the poorer range condition that still remains on this on the east side of the fence and now on this recently converted cropland that they had they sprayed out the grass and in planted corn so on the good condition range we had 10 seconds on the forward condition range we had seven minutes and I’m on this recently converted cropland we had 31 minutes over 31 minutes we will have the tremendous difference in grass I’m production on rangeland that’s in good condition we will have much more production where you’re infiltrating more water into the ground and each inch of water can grow as much as 150 to 200 inches for the pounds of grass so every answer getting in the ground is going to make that range that grassland that much more productive but what does that mean in terms of runoff all that water that we’re running off that we’re not infiltrating into the soil is going downstream into the Missouri River and running off the landscape we’re not storing that water here on the landscape we’re actually moving that water off the landscape not only that but we’re moving nutrients in the soil from from the soil to keep the plants healthy in the ecosystem sustainable and so we’re taking that wealth of the soil moving it to a to a farmstead or some other place from the soil these infiltration rings are something that a person can do to evaluate these conditions on your own man a lot of the changes that occur in soil a lot of the parameters that we can measure take time to change this individual characteristic infiltration responds very rapidly to changes in management running these kind of tests on your land can give you a really good idea that how your management is affecting the soils and the plant communities out yet another thing that you can look at is the soil profiles on these different management extremes from the good range management to this this range that has been recently converted to cropland so we have over here a couple soil profiles and we want to take a look at those and how visually changes occur in that soil profile due to management so we’ll take a look at this this profile here on this side is from that good condition range land this over here is is right from nearby where we’re sitting right now in the cropland the effects are you’re going to see on these soil profiles really are from the grazing management in the past rotational grazing on the west side of the fence and continuous season-long grazing the differences we see here on these soils that are basically the same has occurred because of grazing management you can see on this where we’ve had good grazing management again you can see the granular structure pretty deep on this one here and we really don’t have it over here but you can see the dark Moloch colors going down quite a bit further into the profile and even continuing albeit lighter they continue on down whereas over here it turns white right about in here and much more quickly than des over here so we’ve got organic matter coming down deeper in the profile then over here with it’s been continuous season-long graze the aggregates or the peds in the profile here are smaller and more blocky but we have over here the pads are almost more NASA van away larger it would appear that there’s not as many pores within or among those peds over here the good we see over here on the good condition range that another thing I think you can see is roots that are extending further down into the profile then you have over here thirty to fifty percent of the roots in a grassland system die off each year and have to be replaced with good healthy grass plants growing above ground that’s pretty easy for them to do when you have poor condition range and continuous season-long grazing like we’ve had food for many years on this side over here you lose those roots over time they cannot keep up with that that turnover of roots and so essentially what we have here is is a retention of that organic matter in this part of the profile from about 12 inches down to to 24 inches and that’s where we see the starkest difference in these two profiles over here this is where the big color change occurs in that that’s subsoil down here where you’ve lost those roots further down that are that have died off here they’re still alive and still recycling that organic matter and replenishing it in the soil so we’ve looked at a number of different characteristics of the soils the plant communities and and how that changes with different management / space and time essentially we’ve gone from good condition range across the fence here to poorer condition range and then taking that already over grazed range if you will and converting it to cropland filling the grass and planting a crop into that and so we’ve seen changes in infiltration changes in the plant community and the structure on the composition changes in production and also changes definitely in the soil in the infiltration in the structure of the soil at different layers and how that impacts runoff an infiltration taking it all the way to looking at a soil profile and the changes in organic matter and structure throughout that profile studies like these show that infiltration is significantly impacted by the management practices being implemented on the land increased infiltration resulting from better management means the water that falls on an operation will benefit that operation changes and management’s don’t have to be drastic to have a positive influence on infiltration and ultimately improve your natural resources and your bottom line I encourage you to learn ways to improve your soil health increasing infiltration being selfish about the rainfall that falls on your farm or ranch

3 thoughts on “Grassland Soil Health: Infiltration

  1. Please notice that the speaker talks about glomalin, not glow melon as is translated in the subtitles. Thanks for the video

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