How to sterilize the soil

Methods for Sterilizing Soil for Seeds and Plants

There are several ways to sterilize garden soil at home. They include steaming (with or without a pressure cooker) and heating the soil in the oven or microwave.

Sterilizing Soil with Steam

Steaming is considered one of the best ways to sterilize potting soil and should be done for at least 30 minutes or until the temperature reaches 180 F. (82 C.). Steaming can be done with or without a pressure cooker.
If you’re using a pressure cooker, pour several cups of water into the cooker and place shallow pans of level soil (no more than 4 inches deep) over top of the rack. Cover each pan with foil. Close the lid but leave the steam valve should be left open just enough to allow the steam to escape, at which time it can be closed and heated at ten pounds pressure for 15 to 30 minutes.
For those not using a pressure cooker, pour about an inch or so of water into the sterilizing container, placing the soil-filled pans (covered with foil) on a rack over the water. Close the lid and bring to a boil, leaving it open just enough to prevent pressure from building up. Once the steam escapes, allow it to remain boiling for 30 minutes. Allow the soil to cool and then remove (for both methods). Keep foil on until ready to use.

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. Place a meat (or candy) thermometer into the center and bake at 180-200 F. (82-93 C.) for at least 30 minutes, or when soil temp reaches 180 F. (82 C.). Anything higher than that can produce toxins. Remove from oven and allow to cool, leaving the foil in place until ready to use.

Sterilizing Soil with a Microwave

Another option to sterilize soil is to use the microwave. For the microwave, fill clean microwave-safe containers with moist soil — quart size with lids are preferable (no foil). Add a few ventilation holes in the lid. Heat the soil for about 90 seconds per every couple pounds on full power. Note: Larger microwaves can generally accommodate several containers. Allow these to cool, placing tape over the vent holes, and leave until ready to use.
Alternatively, 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). Close the bag and allow it to cool before removing.

The role of soil communities in enhancing carbon sequestration

Small soil animals can limit the effects of climate change, a team of researchers has shown through a long-term study. In the same way that Yellowstone's wolves regulate plant diversity by controlling the number of grazing elk, the researchers found that insects, worms and other small creatures can play a similar regulatory role in soil ecosystems by feeding on the microbes that can trigger increased carbon emissions.

The effects of Aluminium on Bee population

Very high amounts of aluminum contamination has been found in bees, raising the question of whether aluminum-induced cognitive dysfunction is playing a role in the decline of bumblebee populations. Aluminum is Earth's most ubiquitous ecotoxicant and is already known to be responsible for the death of fish in acid lakes, forest decline in acidified and nutrient impoverished catchments, and low crop productivity on acid sulphate soils
Aluminium is Earth's most ubiquitous ecotoxicant and is already known to be responsible for the death of fish in acid lakes, forest decline in acidified and nutrient impoverished catchments, and low crop productivity on acid sulphate soils. Now, a collaboration between Professors Chris Exley (Keele University) and Dave Goulson (University of Sussex) raises questions on the role of aluminium in the decline of the bumblebee.
Previous research had suggested that when bees forage for nectar they do not actively avoid nectar which contains aluminium. This prompted the suggestion by Exley and Goulson that bees may be accumulating aluminium within their life cycle. Researchers at University of Sussex collected pupae from colonies of naturally foraging bumblebees and sent them to Keele University where their aluminium content was determined.
The pupae were found to be heavily contaminated with aluminium, with individual contents ranging from between and 13 and nearly 200 ppm. Smaller pupae had significantly higher contents of aluminium.
To put these aluminium contents in some context, a value of 3 ppm would be considered as potentially pathological in human brain tissue. While preliminary, these data have shown the significant accumulation of aluminium in at least one stage of the bumblebee life cycle and suggest the possibility of another stressor contributing to the decline in its numbers.
Professor Exley, a leading authority on human exposure to aluminium, from Keele University said: "It is widely accepted that a number of interacting factors are likely to be involved in the decline of bees and other pollinators -- lack of flowers, attacks by parasites, and exposure to pesticide cocktails, for example.
"Aluminium is a known neurotoxin affecting behaviour in animal models of aluminium intoxication. Bees, of course, rely heavily on cognitive function in their everyday behaviour and these data raise the intriguing spectre that aluminium-induced cognitive dysfunction may play a role in their population decline -- are we looking at bees with Alzheimer's disease?"