Minnesota Farmer

Variations on a theme
June 11, 2010, 7:31 pm
Filed under: Ag education, Farm, fertilizer, food, organic, planting, rain, science, tillage | Tags: , , , , , ,

There is a discussion going on in some areas about the “best” type of agriculture.  Many think that organic farming is the only way to go.  Some are promoting permaculture.  Most American farmers do some variation of “conventional” farming, it could be plow, disk, rip, chisel, strip, ridge or no tillage.  To me they are all variations on a theme.

Permaculture is a no tillage method that seeks to go back to the “natural” theme of agriculture, almost a gatherer type of existence.  Trees and vines are allowed to grow on the edges of fields to provide berries and nuts.  Grass land is pastured with cattle, sheep and/or goats.  Near the house would be pens with chickens and pigs.  Most crops are perennials, annuals are limited to garden crops.  This almost hippie existence is long on labor and short on spending cash.  It can and will support a family, but I’m not sure at what kind of a level.  No pesticides or herbicides are used.  Wildlife thrives in the hedges and fields to harvest insects, goats eat the weeds.

Organic producers also grow food without herbicides or insecticides.  They can produce them at a subsistence level, all the way to large scale agriculture.  Small scale organic farmers may have another job to support the farm and make their sales at farmers markets, or they may operate on a large scale using planters, harvesters and other equipment associated with “conventional” agriculture, plus a few more.  In the U.S. a certified organic producer can expect higher prices for their crop, but can plan on more risks as they raise a crop or livestock.  A bit of chemical drift from a non organic field can result in the loss of the organic label for that field.  Sick livestock are allowed only a few natural remedies and could die before their is even a hint of a disease.

Mold board plows, disk plows, rippers and chisel plows could all be part of a conventional farmers, or even an organic farmers, machine list.  These implements are used to till the soil after a crop is harvested.  They result in differing levels of crop material left on the surface to control wind and water erosion.  In more temperate climates a cover crop may be planted as another way of holding soil, but in northern fields the crop is harvested just before freeze up and getting a cover crop started is impossible.

Strip till requires a special piece of equipment that digs up only the space where the coming years crop will be planted.  Fertilizer is placed in the strip and two disks place the soil back on top.  Very little soil is worked, and thus very little space is open to erosion.  The crop is planted on the only bit of worked soil, right over the fertilizer, thus lower fertilizer levels are used.  Cooler, shaded soil between the rows slows weed germination.

Ridge tillers do their tillage in the summer between their crop rows.  In the spring the top of the ridge is removed and the crop planted.  The ridge is reestablished after the crop is up.  All crop residue is left to protect the soil in the winter.

No tillers do no tillage at all after harvest and very little before the crop is planted.  Either straight or rippled disks will open a small slot, the seed is dropped in and press wheels close the trench.

Less tillage has both advantages and disadvantages.  The crop residue slows wind and water erosion.  The residue also slows the soil warmup in the spring, thus the choice of strip and ridge till by many.  More residue also helps hold moisture and reduce drying of the soil.  Less tillage will also promote more activity by earthworms, mice and gophers.

No mater what types of tillage a farmer may chose, they are all ways of producing a crop.  Tillage will change due to climate, slope, livestock and many other things.  To me they are choices, some better for some areas, many flexible enough to be used in diverse areas.  They are all ways to produce food, all variations on a theme.



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