Understanding disturbance and succession helps us as eco-farmers to use our management to “steer” our site toward greater resistance to pests and disease
Whether we are row-croppers or graziers, what we do to interact with ecological succession determines the health and fertility of our present and future resource base. Let’s quickly review a simplified version of how ecological succession operates from the perspective of an ecological farmer.
At some point in time, some type of disturbance created a starting point for ecosystem development. Let’s say it’s a wildfire. After the fire dies, the exposed rock and soil is at first colonized by annual plants — “weed” seed that was not incinerated — and fire-tolerant perennials sprout up. Roots and root exudates from this first regrowth charge the mineral soil with carbohydrates, from sugars to lignin and cellulose. The soil life begins to thrive on the new food source, and suddenly there is an availability of plant nutrition in order to grow the next successional stage of vegetation.
Beneficial organisms, as well as pests and diseases, find their way to the site. The diversity of plants on the site is low, as is the diversity of insects and diseases. In year one, “pest” populations (corn earworm, cabbage looper, etc.) are somewhat low, but as the years progress, pest populations build up. Fields that have been in continuous corn for half a century, for example, have had that many years of pests built up with no corresponding increase of pest predators, due to lack of habitat. Crop losses can be significant.
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