Green Manure Crop Styles
Catch, Cover, and Cash Crop Concepts Improve Gardens.
Organic gardeners develop their gardens without the use of synthetic chemicals. Often green manures are used as an ecologically sustainable alternative.
Organic growers distinguish between various categories of crops grown mainly for soil maintenance or improvement rather than, primarily, as a main crop. The organic home gardener can easily adapt these principles to their own situation. These crops, often green manures,are used as an ecologically sustainable alternativeto synthetic, chemical ferilisers to protect soil, increase soil fertility and maintain soil structure.
Traditionally, three types of crops that are not main crops recognised:
- Cover crops
- Catch crops
- Cash crops
A cover crop
The concept of a cover crop resonates for organic growers whether farmers in a small way or backyard growers because it incorporates useful techniques.
A cover crop is grown to protect the soil beneath it while it rests prior to replanting. It may stop wind or rain caused erosion, leaching of nutrients, or compacting of the soil. Also, leaving a patch of ground denuded for too long is likely to increase the weed problem because weeds are discouraged by a vigorous cover crop. There can be a case for winterising the bare soil where soil freezing occurs, and snow is the poor man’s fertiliser.
The cover crop protects the ground fauna and flora, maintaining the surface and subsurface interactions of these which may include the eating of weed seeds by rodents and beetles sheltering under the canopy.
Finally, the cover crop if well selected, will be able to be turned-in as a green manure.
Allelopathic plantings.
Sorghum is reputed to have a strong allelopathic effect on weeds, Planting this as a green manure cover crop should lead to wholesale weed clearance.
A catch crop.
A catch crop is crops grown to “catch,” hold and preserve the goodness in the soil from the previous growing season. If the soil has been enriched to grow a crop or just a summer’s annuals, this residual goodness can be captured and retained in the growth of a catch crop.
When this catch crop is turned in as a green manure, the nutrients will quickly but progressively become available to the soil and subsequent crops.
Planning
As part of spring planting planning one should plan for the end of the season. One day the daisies or sunflowers or tomatoes will be spent – what will follows these? What will “catch” the nutrients, halt weed infestation, and hold the soil. It does not matter particularly whether you will get the following crop to fruition – this is not the point– if it grows well enough and then is hit by frost, the nutrients will have been captured. If there is to be a winter of violent storms, rain and wind, the crop will hold the soil and stop erosion.
Cash crops.
Using a tract of land to make a cash windfall before or after and certainly between main crops is usually called a cash crop the connotation also suggests “cashing-in” on the manuring and fertilising regime of the “main” crop. Such a planting should be part of a rotation. Carrots should follow a highly fertilised crop: too much fertiliser and they fork, but do well following a green, leafy vegetable.
Green Manure.
The point of catch and cover crops is that, usually, before reaching maturity, these are turned into the soil to add nutrients and organic matter that the soil organisms will use to create a slow release fertiliser
