We're putting in kitchen garden beds on what was a small-grain field (it was probably barley, but I'm not really sure) up to last sunmmer, and is currently grass for hay . The soil is clayey silt, and quite compacted. For this season, we've skinned off the sod layer and 'broadforked' the beds with a digging fork, and set our translants into that with a little topsoil around them, and mulched the beds with with the grass we mowed off before making the beds, . My question is about this winter; our original plan was to just chop and drop all of the plant stems after harvest, and then cover it all with another layer of grass/hay mulch, and let it all break down over the winter, but after fighting with this compaction, I'm starting to wonder if some sort of cover crop might loosen things up a bit better. The problem is, with the late planting, I'm not sure that there will be enough time for a cover to establish before our first frost, which usually happens mid September. So, do ye think we'd be better off just sheet mulching, or doing a cover crop; and if the second, any recommendations of things that will establish quickly/survive a certain amount of frost, but won't be a nightmare to deal with at planting time next spring?
The mulch and chop & drop are good practices to add some organic matter to your soil, and adding organic matter can help with compaction, as are cover crops a good idea as well. Sometimes clay soils have so much clay that one can add organic matter til the next sighting of Haley's comet and not really improve the compaction problem. I highly recommend getting a soil analysis done as it may indicate your clay soil is deficient in calcium and may also possibly have high magnesium levels. I say this because calcium will keep clay soil particles from sticking together making for loose crumbly soil, and high magnesium levels will cause soil clay particles to stick together causing compaction, poor drainage, and low oxygen levels. If calcium is brought to adequate levels, the worst clay soils will magically loosen up, allowing water to flow thru, and oxygen for microbial life and roots will increase. There are other factors in soil tilth like organic matter, humus (which is organic matter, but not all organic matter is humus) and other aggregates like sand particles which should be in your soil, and a different kind of soil test can give you those percentages if you're curious to know those. Your clay like soil will have a high cation exchange capacity (it's ability to hold onto some of the elements necessary for soil and plant life like the aforementioned calcium and magnesium) so it may take a lot of calcium to loosen up that clay. And there are different ways to get that calcium in there. If the soil pH is low, calcitic lime is great. If the pH is low and it happens that magnesium levels are not high and need boosting, dolomite lime can be used only if magnesium is needed. If the pH is near ideal, gypsum is great to add calcium without really modifying the soil pH.
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I have very heavy clay and two things have helped immensely. A couple months before your first frost hits, plant tillage radish. It grows huge and makes nice big holes down anywhere from a foot to two feet. It diesa after a few cold days and rots over the winter, leaving nice holes full of organic matter for the water to get thru. Also, use heavy mulch of whatever organic material you can find. If you plant your tillage radish in rows, mulch between them as the get big enough. If you broadcast the seed, mulch as early in the spring as you can after the snow is gone. The best advice I can give you with clay soil is never, ever, leave it uncovered. If you do, it will bake hard as a brick and you will be starting over until your organic matter builds up in the soil.
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Fodder radish as we call it is a good plan, however it does reduce your cropping time this year. Your season is short Daniel, but brassica plants are good because they survive the first frosts of autumn, until the radish dies below about -6C.
In 1999 I improved an area of compacted clay, which cropped poorly in year one, by mulching with well of half decomposed horse manure, and no forking. Composts and manures feed soil life more quickly than undecomposed materials (the chop and drop), so in damp climates I find it better to compost materials then add them decomposed. Yes it's more work but you are increasing soil life more quickly. And have less slugs.
Another consideration is how much land to crop. Larger areas that are short of mulch are more work than smaller areas of well fed soil.
Thanks for the tips! I'm afraid that commercial soil tests are going to have to wait till next year: we've *just* gotten the place (we actually don't take occupancy till August, but the previous owners said we could put in our garden before they move out), and after the purchase, repairs, getting fencing and stock, etc, soil tets don't fit our economy at the moment. I've done a jar test (about 2/3 silt, 1/3 clay, no noticeable sand at all), and if I can ever remember to bring the distilled water with us when we go over to plant, I can test the pH, and when we get access to the house, I can do a basic soil organic matter check, but that's going to have to do for now. It really sounds like planting daikon is going to be the way to go, at least in the beds we haven't planted yet. When it comes to the beds that *are* planted, I'm thinking of sowing the daikon into places where either things didn't come up, or where I've harvested. Are there any plants, other than legumes, that wouldn't do well with daikon as a neighbour?
Charles, compost and manure are *definitely* both in the plans for the future: it's just that at this point we don't have any of either of them, and we *do* have the grass, so we've used that Fortunately, slugs aren't a problem up as far north as we are- though they seem to be moving north a bit every year, so we'll see how long that holds true... We've only put in about 100 square meters this year, so keeping that mulched shouldn't be too much of a problem, and next year we 'll have compost and, hopefully, manure to work with, so we'll be able to expand things some.
Again, thank ye for the advice!
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