So a local legend watermelon grower told me one of his secrets is subsoiling the rows before planting. I have yet to get further details about specifics. Our farmland is basically the same, sandy/silty/rocky river bottom soil. Drainage has never been a concern that I’m aware of. Would this help roots travel deeper?
I did see 1 study from Auburn University that suggested sandy silty soils might benefit greatly from subsoiling. But strangely this one guy is the only person locally I know who does.
Does anybody do in-row subsoiling before planting the garden or fruit trees/vines/bushes?
How about grid pattern subsoiling new ground?
Any other subsoiling experience please report here.
Subsoiling means to rollover the bottom soil to the top and vice versa. The idea is the top layer of soil is pretty warn out it has been farmed for years. If you can get organic material in the ground and soil nutrients eg. Clay on top it attracts worms, loosens soil etc. He is likely going 1-2 feet depth.
Subsoiling won’t help roots travel deeper unless the soil has compacted layers that restrict root growth. It’s a practice that’s very soil specific. Sandy/silty/rocky doesn’t sound like soil that would limit root growth. Chances are in that situation it’s not worth the effort.
Agreed that soil tends to have no nutrients deeper. Subsoiling is usually done in clay - loam like ours in Kansas. Farmers subsoil about every 10 years here. As @murky said compaction can be an issue but not in sand or silt. This is the concept jevons uses with the double dig method. It adds old crops and organic stuff underneath. The field looks like it is solid clay afterwards.
By definition, subsoiling is non-inversion tillage below a depth of 14 inches… so it’s not the same as ‘turningl over’ the soil, as with a moldboard or ‘turning’ plow.
So… a subsoiler loosens and breaks up the soil about twice as deep as most plows/harrows go, but does not bring the deep ‘subsoil’ up and flip it over on top of the (previous) surface soil layer.
I can see the utility in badly compacted soils, but would not expect that to be a significant issue with a sandy soil.
Some years (decades?) ago there was a book out that endorsed “double digging”. It advocated using a special very long-tined fork to get down perhaps 18"-24". Raised or mounded beds were part of the plan. This might be the work I’m thinking of: Double Digging | The Method and the History . Not sure if that’s the same as “Subsoiling”.
It was based on work done in California. I don’t think they would consider it in my river bottom subsoil.
Extreme versions of this can be seen in the Netherlands where they periodically practice “deep plowing,” turning soil at depths up to 48”! They use rows of bulldozers attached together to pull these plows. It’s done to bring up sandy and more nutrient rich soil above the clay (where they will eventually intermix).
As an example someone once asked if i used a swather or a rake and sickel. The truth is i used all of them depending on the situation. The large plows used here are mining subsoil they are going much deeper than a traditional plow. The tractors are huge and that equipment pulls hard. This is the technical usage @Lucky_P correctly referred to The Art and Science of Subsoiling | Mossy Oak. The problem is even though the layer of clay is broken with a subsoiler it will reform hardpan quickly unless it is rolled. It ripped through it but the clay that formed 1 foot down into hardpan will simply reform into hardpan. If you have ever made clay pots or felt clay from the field in your hand you know that clay does the same thing again unless it is physically broken up and moved to the surface. Slicing hardpan soil is not a permanent solution.
I think the objective we’re all referring to with subsoiling is breaking through the hard pan. Super sandy soil wouldn’t have a hard pan, but you and I sure do with our black clay soil.
My plan instead of subsoiling is to plant tillage radishes. My tractor won’t pull a ripper deep enough to break my hard pan, which is significant since my orchard was a wheat field for decades. I’m in a river flood plain, and soil samples I’ve taken with an auger show sandy loam at 3’. Water will stand for weeks above it supported by my hard pan, but it drains well enough below that.
Yes unless the subsoil clay is flipped it does the same thing the same year. This picture gives you a sense clay is underneath that loam. If that layer is left intact it just repacks as it was in no time. The good news is it makes great ponds. Berms and swales - terracing - creating water ways
“Annual subsoiling of all agricultural soils in the southeastern Coastal Plain was and is still recommended.
In a two-year study in Alabama, in-row subsoiling gave different results on two soil types  when compared to no subsoiling. On a sandy loam, with a hardpan at an 8-inch depth, annual in-row subsoiling was conducted prior to planting by pulling a shank through the soil to a depth of 12 inches. On a silt loam with no hardpan, in-row subsoiling was conducted to an 8-inch depth prior to planting. For the sandy loam soil, in-row subsoiling produced the highest cotton yields for both years of the study. For the silt loam, significantly higher yields for in-row subsoiling only occurred in the first year of the study.”
Thats interesting that it gets compacted like that. Here are a couple of tricks i use to deal with the water and the soil since i grow hay and fruit now and not row crops. The hardpan is something i live with now. https://growingfruit.org/t/ponds-are-a-great-investment/7033
Catch the snow in the same way where it doesnt just sit in the fields.
I have experience with subsoiling. After we completed clearing our orchard site I subsoiled the field with a single shank subsoiler. While the soil here is sandy, the field is shaped like a bowl and collects spring melt off. I wanted to be sure to encourage drainage and didn’t want to disturb the thin topsoil at the site. The subsoiler also served to break up remaining roots from the nearly 1000 trees that were removed. After running through the entire field, I laid out the orchard rows and before tilling the row for planting I ran down the middle of the row with the subsoiler once again. The point of the subsoiler is to avoid soil inversion while improving aeration and drainage.
@AndySmith that is similar to my situation. Presently clearing a few acres of ~1000 pines, 15 dead white oaks and a dozen magnolias. My thought was to run a single shank subsoiler to breakup remaining roots and increase drainage and aeration. This area has some topsoil but mostly clay. I’m planning to bring in some fibrous leftover biproduct (neutral pH, minimal np3 values) from a local paper mill to disc in after I finish clearing. They do this and replant pines everyday.
My current orchard is located in a river bottom field, parts of which are rocky/Sandy but some good soil too. Not sure how beneficial subsoiling might be there.
The one way, breaking plow and ripper are all practices that were once common but are now rare. Chemicals have replaced the need to bury seeds and rhyzomes too deep to emerge and cover crops have reduced the need to break compaction in most cases. Sunflowers, rye or milo will penetrate and make pathways through a compaction layer. Of course, if you have to harvest in the mud and rut the field you will have to work them out. In my experience, tillage radish is more advertising than anything. In truly compacted soil, the radish grows up instead of down.
I’m not sure how beneficial it was in our light soil, but after the big equipment finished pulling stumps I felt compelled to do something for the compaction they caused. We had thought we would be able to pull the pines with the Ford 5000 but realized quickly that wasn’t going to work. My thought was it’s my only chance to do so before planting out. I would expect your clay soil conditions to benefit from some subsoiling. I don’t think I could have used the subsoiler had the track hoe not so effectively removed the stumps (it wasn’t cheap, but not as bad as some contractors were suggesting).