How long will past chemicals keep soil dead?

I have been offered some soil which has been heavilly chemically fertilized ( no herbicides or insecticides) and was wondering how long it would take to bring this to the point it could support earthworms and microbial life again. Is there any data anywhere?

The soil I have is almost total sand so I am tempted to take this stuff and so get something at least growing there  that can be used as a base for building real soil. I have very little compost and buying it is not an option. Does anyone know how long it takes before the chemicals are dilute enough that the soil can start to rebuild itself?

I'm pretty sure that chemical fertilisers are water soluble, so a few good rains will wash most of them away.  If the soil is too dead, there won't be enough decaying matter to feed much by way of earthworms and microbes, so anything you can add will speed up their return.  If you can't buy compost, could you find a source of mulching materials?  Straw, leaves, hay, horse manure - almost anything that you could spread around will eventually decompose enough to allow the life in the soil to return.

Have  you actually had a dig in the new soil - if there are any earthworms at all in it now, it's a sign that they should be able to increase their numbers pretty quickly given improving conditions.

thanks!   No no earthworms in it at all, it was greenhouse soil and they are quitting and selling to  a developer.  I was thinking of getting composting worms come spring and warmer weather and making a bottom layer of compostable  stuff so  hoping the chemicals residue wouldn't kill them..I know that the composting worms won't live long outdoors once the weather is bad but thought it might be another way to help things along..or will the worms eat the new plants? yikes! Never thought about that!

The earth worms should not hurt your plants,  don't worry about that at all.  The chemicals should be gone,  washed away fairly quickly.  I have heard that some states require a farm to be chemical free for 4 years befor they certify it a " Organic "  but I am sure all of the chemicals are long gone  befor the 4 years are up.  I dont know where you live,  many communitys collect leaves in the fall and have them in a large mulch pile.  You maybe able to get some of them free for the hauling.  Grass clippings work well as much and many people who bag their grass are very happy to get rid of it.  Mulch hay is also good but you might have to pay for it.  If you look around you might be surprised at all of the places that free much can be found.  Think this way,  if it came out of the ground it can go back into the ground,  just that simple.  Good Luck with your new property,  I am sure you will have it Blooming in no time at all. 

You can innoculate the dead soil with micro- and macroorganisms by digging up a spade of healthy soil elsewhere. Just put the spade of healthy soil on top of the dead soil, don't work it in. Cover the soil with mulch. The micro- and macroorganisms will spread out and reclaim the soil over time.

imo it depends on how badly the soil was managed, and how you plan to restore it. but there is hope.

i have turned some VERY bad soil into fertile life giving goodness in 2 years. eventually the worms will return all by themselves. its amazing how worms can find fertile soil somehow, even though they live in a vast ecosystem and they move very slow. i did an experiment where i only restored a 2x2x2 area in the middle of a biologically dead field, not a single worm to be found and i looked for a good while. within a month worms moved in and were flourishing, even though there was a huge area of "dead zone" in all directions surrounding the test plot. still curious as to where they came from and how they found that sweet spot.

back to the soil restoration, what materials do you have available to you, oh and how much area are we talking?

I have lots of straw and sawdust  but the straw is long, not chopped, so it will take a while to break down, and I had thought mostly to use it as a mulch. I used sawdust and grassclippings  to make up some growboxes  last year in another location and they worked really well but the people with the grass clippings got inspired and now are using them themsleves 

I may be able to get a whole bunch of grassclippings each week from the village though, once the lawn season is well under way, so planning on that, and, later in the year , on the bagged up leaves that people set out for the dump. I am working on the local coffee shop for coffee grounds, but all of this is alien to most people here so that's not working as well as hoped.  I got enough to start some mushrooms but that's about it.

Some aged cattle manure might be possible.

Altogether there is  80 acres, about half is cleared. There is a patch of soil about 100 feet x 70 feet where the horses have been eating hay for the past two years and I thought to try to get a garden going in there. The major problem is the soil is SO sandy that moisture retention ( and the nutrients in the water) is the major issue.  Once a garden is in then keeping stuff watered may become a real headache unless I can get stuff in there that will hold it (which is where sawdust will hopefully shine.) The sawdust  used last year was boosted with dilute urine and the plants showed no sign of nitrogen deficiency, but they did show minor calcium problems. I'm not sure if that would still be the case with actual soil mixed in or not. Oh yes also have probably about 80 pounds of wood ash, and I am looking to find barrels to make some biochar. There is a lot of "waste" wood  from the place I get the sawdust. Some is usable as lumber but  much of it mostly only good for burning. Since that's  not such an issue in the summer I thought to turn a lot of it into biochar.

I was thinking about wicking beds but really dislike using plastic like that..too bad nobody makes long sheets of biodegradable plastic from corn yet! So then thought about trying to make a sort of composting area below the "soil" area and putting composting worms in there so that hopefully by the time the roots got to it it would be soil:)  Whatever else, I intended to use straw as a heavy mulch on top.

Another issue is that I have just got access some sour cherry, hawthorn , seabuckthorn , haksap  and 30 hazelnut bushes come spring and really need to give all of them a good situation to live in. 

Ideas and suggestions are really welcome. 

Pam, my land is also all sand and very fast draining.  I am going to try hugelkultur this spring and see how that works.  I would love to have some BAD soil to work with, just don't know where to find any.

Good Luck!

Hi Pam, if the chemicals are chemical fertilizers, I think it would be an excellent idea to use sawdust to soak up the excess nitrogen and fertilizer salts and use it to compost it quicker and convert to humus. This may take a few months. I recommend infusing the soil with compost teas or vermicompost teas.

soil wrote:
imo it depends on how badly the soil was managed, and how you plan to restore it. but there is hope.

i have turned some VERY bad soil into fertile life giving goodness in 2 years. eventually the worms will return all by themselves. its amazing how worms can find fertile soil somehow, even though they live in a vast ecosystem and they move very slow. i did an experiment where i only restored a 2x2x2 area in the middle of a biologically dead field, not a single worm to be found and i looked for a good while. within a month worms moved in and were flourishing, even though there was a huge area of "dead zone" in all directions surrounding the test plot. still curious as to where they came from and how they found that sweet spot.

back to the soil restoration, what materials do you have available to you, oh and how much area are we talking?

I agree with this.  No need to buy expensive worms - it's just a waste of money really.  To the member who recommended digging up healthy dirt and spreading it out I think compost tea would serve a similar purpose and would be easier to do en masse rather than moving lots of soil everywhere and breaking your back for it.

You can start improving your soil immediately. You should keep on improving your soil through out your whole life. There will never be a threshold level where in you can call your soil alive again, it was always alive (it's not like waiting for an herbicide to drop below a threshold level to call it safe for plants again).  If you treat your soil well it will be richer in composition and in biodiversity in a year than it is now.

Nathan Johns wrote:To the member who recommended digging up healthy dirt and spreading it out I think compost tea would serve a similar purpose and would be easier to do en masse rather than moving lots of soil everywhere and breaking your back for it.

Well, you can't mean me because I #1 said: "Don't work the dirt in" and that includes "spreading it" and #2 "only a shovel full of dirt" which is easily carried in a basket. To the idea: It's just a clump of dirt you lay intact on your field. Never watched Bill Mollison's permaculture in temperate climates?

soil wrote:
i

i have turned some VERY bad soil into fertile life giving goodness in 2 years. eventually the worms will return all by themselves. its amazing how worms can find fertile soil somehow, even though they live in a vast ecosystem and they move very slow. i did an experiment where i only restored a 2x2x2 area in the middle of a biologically dead field, not a single worm to be found and i looked for a good while. within a month worms moved in and were flourishing, even though there was a huge area of "dead zone" in all directions surrounding the test plot. still curious as to where they came from and how they found that sweet spot.

Could you give some specific  on how you did this?  I am still of two minds whether or not to take this stuff..some chemicals don't exactly disperse as quickly as they are claimed to do..and if they will simply filter through instantly then I have to consider what I might be doing to the groundwater.

Nathan Johns wrote:
I agree with this.  No need to buy expensive worms - it's just a waste of money really.  To the member who recommended digging up healthy dirt and spreading it out I think compost tea would serve a similar purpose and would be easier to do en masse rather than moving lots of soil everywhere and breaking your back for it.

Worms can be had for cheap if you find the right person or a friend...or you go digging for them. Watch the robins. It's a better deal if you're getting them to recycle kitchen/household waste for you. The best worms, though, are natives, who are more diverse, adapted locally, etc. Vermicompost tea is great for stimulating the soil. I've tested the effects of some different types of compost teas I've brewed, and vermicompost tea is one of the best. I use it all the time now.

Pam wrote:
Could you give some specific  on how you did this?  I am still of two minds whether or not to take this stuff..some chemicals don't exactly disperse as quickly as they are claimed to do..and if they will simply filter through instantly then I have to consider what I might be doing to the groundwater.

Pam, part of the problem with heavily fertilized soil are the sulfates, nitrates, and nitrites that result. Sulfates lower soil pH to the point where it pickles stuff, and nitrates and nitrites in excess are deadly to soil microbes and earthworms, burn off soil organic matter, and promote anaerobes. For example, nitrites are used as food-preservation chemicals for like ham, bacon, etc. When people are putting fertilizer on their lawns, I imagine the earthworms are being pickled and preserved. Horrible for them.

If it's mainly these type of chemicals, I believe they can be dealt with and cleaned up in no time at all. Applications of organic matter will encourage the growth and proliferation of earthworms and soil microbes. Woody things like sawdust, bark, chips, branches, etc. require large amounts of nitrogen as they decompose and turn into compost, so they are very useful for binding and negating excess nitrogen fertilizers. SOM will dilute and tie up excess sulfates. With these reduced, the soil life will flourish.

However, if there are any things like organophosphate or chlorine/bromine-type of chemicals which are common in pesticides, herbicides, bleach, etc. these are more difficult to deal with, because they are broad-spectrum chemicals that kill a wide variety of soil life and microbes, the very things we would use and depend on to decontaminate the soil. It's said that mushrooms and other fungi are useful for degrading these persistent chemicals. If the soil is contaminated with these chlorine/bromine type of chemicals, you'll want to avoid it for sure, because that kind of clean up requires serious bioremediation.

PS: Paul, I hit the wrong button and notified on this post. Please ignore it.

Your initial post said YES on fertilizer, NO on pesticides,  sandy soil,  low organic matter.  We don't know how much land you want to improve, or your climate!

Without more information I throw my vote for lots of organic matter and cations (Calcium-magnesium) like oyster shell.  Any of the innoculation ideas (compost tea, shovel of dirt, etc...) can't hurt, but the critters need food.  And finally... Get something growing... clover perhaps... don't forget to innoculate.

I'd agree with those who say that Nitrogen fertilizer leaches fast while hastening the decomposition of organic mater.  The exception being Phosphorus, which can be retained in iron or humic complexes, however if you soil is very sandy there may be little free iron (resulting in the potential for iron deficiency from historic phosphorus loading).

It really depends on what was applied. Do you know what fertilizer was used? If it's granular or liquid applied, I wouldn't worry about residual (except for a possibly skewed pH), after about 6 months exposed to weather. The reason anhydrous is used in conventional row crop settings is the "stickiness" of it. It really binds to the soil particles, thus reducing the risk of denitrification in a wet growing season (or over winter, as some producers do). Nitrogen can volatilize and leave the soil pretty quickly.

If the nutrient value in the soil is gone (already grow in, and dead), then you don't need to worry about nitrogen or phosphorus runoff and you're just worried about re-introduction of microbes and fungi. However if the soil is chock full of 28% and triple phosphate, I would spread a thin layer over all of you ground so it doesn't overwhelm any particular spot.

Soil will heal if given the opportunity. Even soil filled with fossil fuels and oil contamination can be removed by natural organisms in the soil. Build the organic matter, that will increase the cation exchange capacity of your soil (very important if you want to have productive soil). Sandy soil can be difficult to maintain decent nutrient levels in; so the higher you cation exchange capacity, the better.

Fungicides, growth regulators and other chemicals are also used commonly in the GH, I would personally turn it into a big compost pile and allow rain to leach it at minimum one year prior to using it in a veggie garden.

wow  this is scary stuff  I think maybe I will just pass on the soil and just keep to the longer but safer process.  Thanks everyone who answered.