You soil will sink, more from the loosening of dense clay into pieces. Without organic material the soil level would try to return to "normal" density. The organic material and attending micro-organisms help maintain channels through the tighter clay pieces.

Low grasses will add some organic material especially if the mowings are left on the surface to be later incorporated into the soil by worms and the like. Tall grasses root more deeply and so the root mass will naturally improve the aeration and drainage to greater depth than would a short lawn grass.

So figure some settling.

If organic material did not completely disappear, we would all be walking on several miles of dinosaur poop.

Yes but the tilth of clay is improved by fluvic and humic acids and other "humus" accumulating through decomposition processes. This gel-like material coats surfaces of clay peds.

When you add organic matter to soil it fills in the spaces between the mineral particles, the sand, silt, or clay particles, and that adds volume. This organic matter provides food to the Soil Food Web, those wee microscopic and larger beasties that live in soil. These wee beasties consume most of that organic matter converting the nutrients that are in that OM into nutrients plants can use and if the level of organic matter is sufficient a symbiotic relationship between the Soil Food Web is developed that helps make the environment in the soil healthier for the plants growing there. As the SFW digests that organic matter, just like the food you eat, it is used up and needs to be replaced, so just as your soil level will increase after tilling (because of the air entrained therein) and then it shrinks after water drives some of that air out the OM will increase the volume of your soil and as it is digested that volume will decrease.

Kimmsr, well said. If you want the SFW to remain active, you have to keep feeding it. Good luck. plantnfool

If you leave your garden wastes on the soil every year, is that enough to feed the little beasties?

For example, I cut all the leaves and stems from my tomato, pepper and squash plants up at the end of last year and left them lying on their respective beds. I will be supplementing that with a small amount of my kitchen compost in each bed, but should that be enough to keep feeding the beasties?

Eventually. Of course, pests and diseases present in your current crops might just be nestling right there awaiting replanting next season.

Eventually. Of course, pests and diseases present in your current crops might just be nestling right there awaiting replanting next season.

Well, I do rotate crops in hopes that it will help stem any overwintering diseases or pests.

Except for strawberries or asparagus because I don't rotate them. I removed the old leaves from the strawberry plants last year and put them in the compost.

Should I add any seed meals, just in case it isn't enough to keep the beasties fed? And where can I get these seed meals? I don't think I've seen those types of things in gardening centers. Also, what is local to me? I live in Ontario, so I don't think cotton seed meal is going to be available here.

You must have lots of canola/rapeseed meal up there along with waste wheat/barley/rye/corn seed and meals usually fed to animals. The waste is pretty cheap for the amount you need.

If you are applying green garden waste to your beds, decay happens pretty quickly. Unfortunately, you lose nitrogen stored in the green waste in two ways. Much of the nitrogen will gas off in surface decayed material or be washed away perhaps. Later when you cultivate the bed, you stimulate denitrifying organisms in the soil thus releasing more nitrogen to the atmosphere. Carbon will build in the soil however.

Whether the end of season waste left on the garden is enough of a food source depends, how intensively is that garden seeded? Does the humus level in the soil increase or at least stay the same? Are flowers or is any produce removed from that garden?
If you feed your soil properly rotating what you grow is unnecessary, and unless you seperate the new bed from the old bed by at least 300 feet it will really accomplish little. How many problems with growth do you see with the Strawberries and Asparagus that you never rotate?

I guess part of the answer has to do with how was your soil to start with. Soil samples sent to the ag part of government will give you a start on how good the soil is. Keep in mind that they will likely tell you to add some 10-10-10 or some such. You may have to figure out what your own version of NPK is going to be.

You must at least replace what you took out. If you took off X amount of produce you must add roughly that much nutrient back just to break even. If your soil needed some building at the start of last season then you need to add extra. I look at what mother nature does to build the rich soil in the deep woods. Permanent mulch is part of my answer. I keep adding whatever plant material I can get hold of along with manure from a local cattle operation.

As to my own NPK regimen, I have been adding bone meal a 20# bag or two at a time for several years. Phosphorous builds up over time especially using bone meal. It is slowly released and takes several years to break down completely. Nitrogen I use kitchen wastes, rabbit feed and chicken mash sprinkled on and turned under. Coffee grinds from work and home add to the Nitrogen added. Also I use old hay and leaves for mulch and I fancy they add a small amount also. As for Phosphorus, I heat with wood and add my ashes to the garden as they are made through the winter. I have not had my soil tested but when I turn it up it is full of worms and all kinds of other soil organisms. My crops produce so much that I often have a hard time dealing with it all. I think I am OK.

Whether the end of season waste left on the garden is enough of a food source depends, how intensively is that garden seeded? Does the humus level in the soil increase or at least stay the same? Are flowers or is any produce removed from that garden?

Produce is removed from the garden, but a small amount of compost is added. Depending on the crop, I've also added a small amount of either bonemeal or bloodmeal. I'm curious though if it might be better if I add some seedmeal instead.

If you feed your soil properly rotating what you grow is unnecessary, and unless you seperate the new bed from the old bed by at least 300 feet it will really accomplish little. How many problems with growth do you see with the Strawberries and Asparagus that you never rotate?

I rotate them to try to keep a buildup of pests in the soil at bay. I've had some problems with the strawberries but have removed all the old leaves instead of letting them sit all winter. I'm hoping that will help for next year. I did it with my mint (in a container)and the leaves all grew back nice and green with no rust, so crossing my fingers it works with the strawberries.

I plan on doing the same with asparagus, removing all the fronds after they die and either burning or composting them. I figure with the crops I can't rotate it would be better to remove the old foliage rather than leave it lay on the soil. No sense in inviting disaster. The plan is to add a couple inches of compost on the asparagus bed every year.

I'm just wondering about this whole new idea of feeding the soil directly with seedmeals instead of with compost. I don't understand the concept fully at this point, but I've seen a few people here talk about it and it's sounds like it makes sense. I've sometimes dropped my half finished compost into the garden before I plant, sort of like trench composting and haven't experienced the problems people warn about. (Tying up the N in the soil) In fact I have seen that the plants over the trench actually grow better.

So, maybe leaving the plant wastes on the soil for OM, and some seedmeal to feed the beasties over the long run. I'm just running this through my mind and considering this new approach as an experiment for the new year.

Anybody who has used seedmeals on their garden, maybe you could tell me if I am going in the wrong direction?

We add meals when spreading and tilling in compost. The little extra nitrogen keeps the bacteria from sucking up nitrogen from the soil to do their things. When the beasties die, some very nice nutrients become available. In my location, that peaks (according to soil tests) between 6 and 12 weeks following. So putting on a lot won't give is early nutrient return unless you till and so disturb the growing bacterial and other microbeasties.

Do worms do well with this regimen? Do they like the grains as much as veggie scraps?

I suspect that they prefer the more easily digestible veggies and associated breakdown products. You realize that green vegetables are mostly water. Adding and inch of chopped up lettuce leaves is not adding much biomass.

What your goal should be is to build up the humus level in the soil, the residual organic matter, what the Soil Food Web does not immediately digest. Will seed meals do that?
Keep in mind that plants have evolved, over eons, to grow in soils with a certain level of organic matter, although some will grow better in leaner, meaner soils. While seed meals may provide a known level of nutrients, over eons plants have developed relationships with the Soil Food Web we do not understand and the most important part of organic gardening is feeding that Soil Food Web, and that requires a mixture of organic matter not just one type.

That must be tough to achieve in forested stands of limited species (lodgepole pine, eg.). In undisturbed soils of at least temperate moist regions, there is some incorporation of organic material into the soil by macro-organisms but by far the larger contribution comes from root systems giving off sugars and cells to symbiotic fungi, bacteria and the like.

We make a mistake of trying to emulate a natural edaphic ecosystem when managing our deeply disturbed horticultural and agricultural zones. Using principles of microbiology is valuable but perhaps expensive and for sure not well understood. In natural systems there are many primary and secondary and tertiary consumers driven to reduce biomass and other organism to exhaustion. In our gardens and farms we kill off or drive away these competitors leaving a very depaupered complex of organisms.

End of preaching