Can Tilling be Sustainable?

I think this question deserves some permaculture reasoning.  Tillage is a cultural practice. It is a disturbance of the soil. Permaculture planning for sustainability requires determining the amount of disturbance  achieves that goal in the overall goal.  First level of disturbance: cutting off the plants that are there; affect the wind rain and sun disturbance.  Second level of disturbance covering the soil for example with mulch which adds the complexity of that being incorporated into the soil over time or removed when the desired effect is completed.   Third level of disturbance is pulling the roots which exposes the soil and seeds to signals that they should grow and cover it back up.  Fourth level is turning the soil over so a deeper layer of soil is on top of the surface soil and what was on the surface.  That requires the reorganizing so that buried soil becomes deeper soil and the deeper soil become top soil. is that what you want to accomplish your goal and can you sustain it as a continual practice or need it for an immediate goal?  Fifth level of disturbance is to mix all of the soil and other things down to a certain depth. That requires the soil life that survives to restructure itself.  

With good planning any of them can be sustainable and even combined in sustainable ways.  Therefore tillage is one of the elements to  be determined in your permaculture plan.  Each zone of the plan has its most favorable level for sustainability.

Cécile Stelzer Johnson wrote:

Dennis Barrow wrote:I don't have a broadfork, but do loosen the soil with a shovel, just don't turn it over, (unless a have some unwanted plants, ((weeds)), that I want to kill the roots.),
but that loose soil I create is perfect to plant some seeds in.  
I am slowing doing this with squash plants as I expand my garden.  The roots break up the ground good and the plants block out the sun so the "weeds" don't grow.  
I did consider renting a large tiller to do a bigger area in a shorter time period, but figured I didn't want to disturb the soil that much so basically poking a hole in the ground seems to work really well.

Depending on the soil you have in Montana, a conventional fork will work quite well.

Cecile, I have tried a pitch fork and it only works in a small area.  I found the shovel works everywhere.  I live up in the mountains next to the continental divide and don't have a lot of good soil.  It has taken me several years to create an area that I can grow without bringing in soil.  I have done that though in another garden area where I have raised beds.