I have a project that will require clearing about 2 acres of good topsoil. Topsoil layer is about 18 inches thick. The topsoil grades into an underlying layer clay loam soil. The topsoil will be stockpiled and then spread back over some clay berms. Clearing with a small dozer (D4 or D6 size). The location is currently in native tallgrass prairie. The big bluestem was over 6' tall this year and the roots go down to 8' in places. I assume you want to eliminate as much organic crap as possible from your topsoil stockpiles? My question: What is the preferred practice to get rid of surface vegetation when stockpiling topsoil? I do small patch burns every year for land management, so that may be the best option. However, I want to work this area when it is hot and dry. I could have a "no burn" rule in effect. Then do you mow close, disk it in, etc.? The best answer may even be, it doesn't matter - just strip and pile. This leads to my second question: Which way do you err on stripping to stockpile? Do you cut deeper and include a little of the underlying undesirable material into your stockpiles to make sure you grab 100% of the good stuff? Or do you leave back a little of your desired material to make your stockpile as "clean" as possible? This question may be moot anyway. I am a rookie operator, so there will not be great precision in the stripping. I just wanted to learn the best way to proceed on the job from some experts! Thanks, Rod
What type of project? Building, road, pond? How much cut and fill in CY's?
Pond project that includes some small forage ponds. All will be excavation-type ponds, since the slope is only 30'/mile. (We have a good live creek for the source water.) Probably 5,000 to 8,000 cubic yards (in the bank). That loose volume will make some pretty large berms. My main goal for the topsoil is to get the clay berms covered and re-planted to grass after the job. No space restrictions around the site - it is out in the middle of one of our native grass fields. I may have to clear a few trees at one possible site. I need more soil samples before the final location is set.
Not familiar with your type of grass but here I would bushhog it prior to stripping. The grass will break down in the pile and smell like s#hit but should be good nutrients. When we strip topsoil on a larger job such as this it's a "get most of it but don't waste time on getting every bit out". On a 8,000 CY cut/fill job any remaining topsoil will be thoroughly mixed in with all the earth moving. Basically there wouldn't be a significant amount of organic material to cause any structural issues for a building pad or road. Sounds like you need to make sure you have enough topsoil to spread back over your berms. I would err on the deeper strip in order to have some left over, any excess can be spread in the field. Your berms, if used for holding water in the ponds, should be compacted to at least 95% density so the volume change shouldn't be that much.
As CM said. Around here we would just mow it off first and strip it all as one. The grass/weeds will blend in and you will never see them on the respread. We generally tend to strip down to 100% good dirt. That gives you a tad more topsoil to do your final dress up with. Also something to keep in mind, we usually strip the topsoil going downhill since it’s easier to push the loose topsoil back up hill than it is to strip the topsoil going uphill.
It’s easier to lose extra top soil then find it when you don’t have enough.
I always found that you need more topsoil for re-spreading than you think it will take. We always stripped into the marginal material as guarantee to have plenty of topsoil for re-spreading. On many jobs when we short on topsoil I had to mix top soil with the underlying dirt to get what the inspectors wanted for depth. Of course the blending was never done when they were near-by !
Thanks everyone, lots of great advice! I am placing the spoils about 20' beyond the shoreline, so I should have said these are "spoils berms" to be covered with topsoil. However, the comment about compaction made me realize that even these berms will be somewhat compacted just by the dozer. I was calculating the height and length using a 25% increase in volume from bank yards to loose yards. I think this is too high. Another question. What is the ball park estimate for the FINAL volume increase of the spoils AFTER being built back into a berm? Material will be mostly loam clay and clay. It will be compacted by the dozer while pushing spoils and then again when grading the top and slopes. Max height will probably be 7-8' with a 4:1 slope for mowing. I need to know the volume of the spoils to estimate the centerline of the berm in my site plan.
Most of our projects the finished product is either building or paving with very little green space needing topsoil. However topsoil is always in demand. If I wanted to fool with it I'd buy a single axle non-CDL dump, put a sign up on the job and sell little loads for cash. . For the majority of the soils we move here in Central AL I use 25%. However soils are as different as there are models of cars.. Here is a basic chart with some shrink/swell factors - https://www.projectengineer.net/swell-factors-for-various-soils/
There is no compaction created from a dozer going over it. If you want compaction the dirt has to be spread in thin lifts with a compactor of some kind. Sheepsfoot rollers are the best there is, if the material is dry enough. For a berm, the dozer tracking it in will be good enough.
I disagree Tinkerer. Compaction can be achieved with thin enough lifts, correct moisture and your bare feet, time is the only variable. A professor at Auburn University first told me that. The rumor I've always heard on the history of the sheepsfoot roller comes from Roman times. The Roman's built a vast road network still in tact today in which they had to have a large amount of humans to build the cobblestone roads. As the story goes they brought along flocks of sheep to feed the workers. They would corral the sheep in pens on the preceding section of road way that had been prepped for the stone cobbles in order to compact the subbase. Thus the term "sheepsfoot" roller. Or it's total bunk and it's named after the studs on the roller that doesn't really look like a sheep's foot. Who knows?
Naaaaa.
Taking the time to mow it down is really worth it when it comes to laying it back out, a lot less bunching of vegetation. Rather than a dozing 2 acres X 18", I would consider using an ag tractor with a pan. So much faster and cleaner looking, and the cost per yards of material moved is cheaper.
Agreed, it's amazing how much compaction tracking over an area with a hoe does even. Or even a backfill with a CTL driving over it 100 times, it just keeps packing it down.
I've heard that, and all I've got is hearsay to support it, but more than one old timer I grew up around said that they'd use flocks of sheep to compact soil for farm and ranch ponds. Two books I've got on local history here mention that method being used. If you go to pick/shovel a trench for UG electrical in a corral area, you'll figure out in a hurry how tight animals can tramp ground over time.