Peak Soil

Here's a straight cut and paste from

http://www.thistlebrook.com.au/peak-soil

1. Keep the soil covered. Soil that has dried out during a drought has a diminished capacity to support microbial life and it’s more prone to being blown or washed away. Spread a layer of mulch, preferably something that will gradually break down to feed the micro-organisms in the soil. The use of cover crops in the veggie patch will perform a similar role.

2. Soil can be replenished. It takes time and effort to do so, but through the continual addition of organic matter to depleted soil, fertility can be significantly increased and microbial life enhanced. An added benefit of soils rich in organic matter is the capacity to store moisture. The easiest ways to improve soil at home are by making compost and growing green manures.

3. Avoid cultivating the soil. No till gardening isn’t practical (try growing carrots in non-sandy soil that hasn’t been dug), but we can all aim to make our practices minimum till. Don’t dig for the sake of exercise, and once soil has been dug, try to implement point one (above) as soon as possible. It’s also a good idea to regularly spell beds in the food producing garden."

So what is "Peak Soil"? Historic collapses of civilisations  coincide with fall in soil fertility due to over-grazing, no time for soils to replenish fertility between crops, and too much ploughing and tilling. The estimate for Australia and its ancient already depleted soils is around 2060. So read the bit above again, be kind to your garden. Farmers in the Big Garden are beginning to learn and adopt better practices.  Your grandchildren's grandchildren will have a future when we change our bad habits.  

Here's another place to get some information

http://www.towardfreedom.com/environment/1496-peak-soil