Hi, 

If you want to sterilize soil you can go for autoclaving. The paper attached can help you at some extent.

Hi, 

If you want to sterilize soil you can go for autoclaving. The paper attached can help you at some extent.

the main method is by autoclaving it. 

Hi.

yes the autoclave is one of best methods. autoclave almost kill every organism in the soil. you just need to search "how to autoclave".

Dear Taab,

The best way to sterilize the soil is autoclaving. You have to fill the soil in good quality polythene bag and then wrap the bag with paper. Keep the bag in the center of the autoclave so that the bags should not touch the side walls of the autoclave. On the autoclave and maintain pressure 15 Lbs and temperature120 0C for 30 minutes. Repeat this process consecutively fot 2-3 days.You will get the 100% sterile soil......This paper may give u idea.....

Article Benefits of Inoculation of Arbuscular Mycorrhizal Fungi on G...

Hello,

I am not expert in this area but in our lab group we freeze it to bellow 0 degrees for 14 days this enables to kill most of the pests that are a problem in our case. But Autoclaving is the best thing to do apart from it.

cheers

We generally autoclave the soil twice at least - but I came across some reports on change in soil structure - nutrient composition/ availability on using high pressure temp situation that autoclave does  - maybe someone can provide information keeping this in view in addition to the paper already cited by Dr Pratibha

From my point of view I would not recommend autoclaving (considered as 121-30min at high pressure) because of the degradation of some organic compounds in the soil leading to potentially phytotoxic products. Partial sterilization with aerated steam (100 degrees-1h-3 consecutive days) or gamma irradiation would provide good results with lower degradation of organic compounds. I attach a paper where they evaluate the effect of the different precedures on the study of AMF.

Hi All,

Thank you for your information and answers/ Alireza 

Dear Azcona,

I agree with your statement that at high temperature and pressure,the organic compounds of soilget degraded, as almost all organic compound are heat sensitive. But we sterilize soil only to assess the changes that happens due to the added inoculum. We are trying to find the affect of certain inoculum on the plant. It hardly matters there that sterilization will effect the results as both control as well as inoculum treated plants receive the same soil.

Autoclaving is a common method to sterilize soil but modifies soil properties and aggregation, and increases available nutrient concentration through the release of N and P from soil bacteria/fungi. As an alternative method I would highly suggest gamma irradiation with a dose higher than 40 kGy which minimizes soil perturbations and does not affect soil nutrient content and mineralization. See Buchan et al. 2012 (Soil Biology and Biochemistry 47:10-13) and Berns et al. 2008 (European Journal of Soil Science 59: 540-550). Gamma irradiation is generally performed by food companies who sterilize cans before sale. This is generally easy and not too expensive to pass by these companies to gamma irradiate some soil, and soil can be irradiated directly with pots or containers. Good luck !

Dear Dr. Rafiq Lone,

I don't agree that it hardly matters. Of course that you have to treat the control in the same way as your inoculated treatments, but I will expose an example of a different output depending on the sterilization of the soil.

Imagine that you have a microorganism that helps the plant to acquire some nutrients by making them more available for the plant. If your sterilization method changes the form in which this nutrient is present in the soil, for example making it more available, the microorganism will not make a big difference when compared to the control. It is just an example, but things can go much more complicated and the soil properties can really make the difference in the results.

The paper I attached before is just one of many examples in literature. Tell me if you need help finding this kind of examples because when you have to discuss your results you should be really taking this into account.

Good luck!

Solarization may be the solution.

Hi ,

Yes you can  sterilize the soil: Sterilization in an autoclave machine for 30 min to 1 hr 120C

I agree with Mr. Mariotte. Sterilization by autoclaving can alter soil properties and this could be a problem if you want to compare your results with an "unsteralized group". There are several publications showing that sterilization with gamma radiation  (about  60 kGy, the dose depends on the biological activity of the material)  is the best way to sterilize soil for your purposes. 

Autoclaving and gamma irradiation are both used but the second is the best.

 Dear Taab,

Sterilizing Soil with Steam: sterilize potting soil and should be done for at least 30 minutes or until the temperature reaches 180 F. (82 C.).

Sterilizing Soil with an Oven: You can also use the oven to sterilize soil. For the oven, put some soil (about 4 inches deep) in an oven-safe container, like a glass or metal baking pan, covered with foil at 180-200 F. (82-93 C.) for at least 30 minutes

Sterilizing Soil with a Microwave: you can place two pounds of moist soil in a polypropylene bag. Put this in the microwave with the top left open for ventilation. Heat the soil for 2 to 2 1/2 minutes on full power (650 watt oven).

For  quick sterilization of soil  is intermittent sterilization for 3 consequent days is prescribed for soil sterilization.

Sterilization by autoclaving can alter soil health either enzyme activity. The best way to sterilize soil   with gamma radiation  (about  60 kGy,) depends on the biological activity of the material.

Attached pdf file for your purpose

We are also preparing for soil seedbank study.  Our intention is to kill weeds seeds, we do not need to sterilize other organisms.  If we use the autoclave for 30 minutes, what is the recommended depth of the soil sample?  We have a lot of soil to prepare and our largest tray is 12" x 6" x 6" tray.  Thoughts?

Dear Christel

One easy way is to have a control sample to check the weed seed species in the soil to count and compare with the treatment sample. Another thing, seeds usually start to die at temperature above 45C depend on duration of the treatment. This could be influenced by soil moisture as well.

Other colleagues shared valuable information above.

Anyway, it is a good idea to have control treatment.

Regards

ALIREZA

Hi everyone, 

I'm running a germination experiment using field collected soil samples, and would like to prevent seeds inherent in the collected soil from germinating along with the seeds I plan on germinating without altering other soil properties, such as microbes - which brought me to this thread. 

Through consultation with others I've established that exposing the soil to a temperature of 60 degrees Celsius for approximately 30 minutes should be efficient. However I would like to have references to back me up, and these prove hard to find. 

Can anyone recommend any references to that end, or if you have a superior method with references I could check out that would be great!

Thanks in advance!

Juan

I'm running an experiment to assess the effects of soil characteristics/type on root colonization and genome evolution of a certain bacterium. We're starting out with a gnotobiotic system, so I was planning to autoclave the soil before planting seeds in it. Should I set aside soil for testing before autoclaving, after autoclaving, or both? I'm not sure whether one of the alternative methods is available to me (although I'll check) and I want to be sure to kill all other microbes in the soil since I will be plating the roots. Any thoughts?

Thanks,

Kelsey

In terms of sterilization of soil, have you considered soaking the soil in Sodium hypochlorite so as to maintain the soil properties and aggregation. Or does it have any consequence on the soil? I intend to employ the method in one of our laboratory study.

Yes soil can be sterilised by contact heating, steaming, radiation and solarization also