Good question. Here I use a raised bed in the middle of the lawn and use the same soil year after year. I've learned in the soil forum that compost is the perfect addition to strengthen your soil. Personally I use it as a mulch and try not to till or shovel much at all. Over the winter the fencing is pulled in and the whole garden is filled with three feet of leaves with any remaining compost underneath. Come Spring the leaves are pulled away and planting takes place without digging at all. This year I did dig some large holes for the tomatoes and mixed in some cornmeal, bone meal, a bit of peat moss, vermicompost and composted cow manure. All was soaked down with Neptune's Harvest fish/seaweed fertilizer and then the tomatoes went in. Regular spraying with Daconil is necessary since the heirloom breeds are a bit more likely to pick up early blight It's been a great season and they always get planted in the same spot. Hope this helps.

Take a look at these websites:

http://calag.ucop.edu/0006ND/pdfs/solarize.pdf

http://bioengr.ag.utk.edu/extension/ExtProg/Vegetable/
year/VegInitReport01/54brassica_biofumigation_increases.htm

http://organic.kysu.edu/biofumigation3.html

http://www.infonet-biovision.org/default/ct/237/
recipesForOrganicPesticides

It's hard to know how adaptable these techniques would be
to your situation but these are at least an introduction.
There are lots of other sites mentioning this. You can
Google for "solarization", "biofumigation", and
"caliente mustard" for a sampling. From what I've seen by
looking at numerous such sites, I gather that rye is a
good choice but that leaf mustard may be better and
tilling in waste from broccoli or raab also can help.

Compost and more compost - both manured and non-manured in the fall. Lots of shredded leaves plus all the spoiled hay I used for mulch during the summer. We also grow various green manure/cover crops to till in in the spring - turnips, legumes, vetch, clover, etc.

Even in Iowa I would think you could get some growth out of a cover crop before winter kill. It would still be a good amendment tilled in in the spring. Don't know about rye but any 60 day crop should get somewhat established if planted now.

Oh, and did I mention compost? ;)

Dave

PS: Search here 'crop rotation' for several prior discussions and you might want to check out the discussions currently running over on the Soil & Compost forum too.

I concur with jbann, with the exception of the leaves. No real reason , I get lots of browns with the straw I use as mulch.
Since one horrible year after I had rototilled as deep as I could I will never EVER deeply rototill again.

Be sure any diseased foliage pruned during the season makes it out of the garden and not into the compost pile!

At the end of the season I turn the soil and straw over about a shovel length deep is all. I suppose if you can control the depth of the rototiller it would save the back but no deeper than the raised amount of compost I grow in.

Then I sow winter rye (sure it will grow there) and let it grow until a nice winter day in mid Feb. then turn it in. It will add copious amounts of great nitrogen in addition to structure. Come March or April I add another yard of compost and turn it in with a broadcast of 10-10-10 fertilizer.... smooth and level the soil. I cover it with tarp then and wait for the trees to do their seed bit so I don't have a garden full of sprouted trees.

Been growing in the same spot for years.

Good Luck'
Tom

Healthy soil is to be desired but if growing in one place all the time I'd be perhaps even more concerned about the buildup of pathogens shed by diseased tomato plants.

And that's another issue that we've addressed here many times.

Carolyn

Compost is the prime amendment along with shredded oak leaves. Compost needs to be cooked a good amount of time or you will transfer even more pathogens. All the more reason for a very good mulching program under and around tomato plants beginning as early as the plants go into the ground.

Too much compost can mean too much nitrogen and your soil may get out of balance. All the more reason for a periodic soil test (cheaply done by the state extension). I had raised beds in central Iowa for about twenty years, growing tomatoes in the same places and had few problems when I was able to keep the soil from splashing on the leaves and stems. For ten of those twenty, my tomatoes were hybrids and the next ten, all heirlooms (now called OPs, etc). As soon as I made the switch to heirlooms my incidence of disease was reduced dramatically. Was it the plants or the care I took of them? I have no idea.

After all the words above, compost and whatever the soil test says for better fertility.

Carolyn..........
Are the pathogens present in the staw used as mulch?

Would they be shed to the soil even tho the leaves and branches were carefully taken from the garden?

Are the roots an avenue for disease back to the soil?
Perhaps removeing the soil around an infected plant would aid in reoccurrence..........

(Don't mean to steal your thread Dean. Indirect Knowledge transfer.......:)