Weeds are nothing more than plants that take advantage of unused resources in areas cultivated by humans. According to the Environmental Protection Agency, a good garden, landscape or crop management program, rather than a chemical pesticide, is the first step in effective and environmentally conscientious weed control (see Reference 1). Proper management and organic methods offer varied benefits over chemical pesticides, including increased biodiversity, improved soil nutrition and structure, and protection of ground and surface water (see Reference 2).
Chemical pest controls, including herbicides, designed to kill weeds have made a huge impact on increased crop yields since the the beginning of their development and application in the 1950s. However, they present a wide array of consequences to human and environmental health, including threatened long-term survival of major ecosystems; a disruption to the natural balance within the food chain; loss of biodiversity; water, soil and air contamination; and chronic health problems for people worldwide (see Reference 3). Herbicides, in particular, also increase weed resistance, furthering dependence on chemical controls, and pose a threat to the genes of wild plant species that come into contact with herbicides or cross-pollinate with treated plants (see Reference 4).
Organic weed control encourages weed suppression rather than elimination. This is done by promoting soil health through a combination of crop rotation, cover crops, biologically based fertilizers, compost and mulch. Healthy soil increases plant health and competitiveness. Natural components of compost suppress weed growth. (See Reference 4)
Proper cultivation timing, plant spacing and seed selection discourage the prevalence of weeds. Planting crops at the time of the year when they grow most rapidly increases the likelihood that they will grow faster than the weeds and beat them to the resources they compete for, such as soil nutrients, moisture and sunlight. A rapid leaf canopy will shade the weeds and discourage their prevalence. In much the same way, closely spaced crops make it difficult for weeds to thrive. Seeds well-adapted to the local climate and soil conditions also ensure rapid growth and healthy plants. (See Reference 4)
Natural Pesticide Alternatives
In some cases, further help is needed to fight stubborn and re-emerging weeds. Herbicidal soaps are effective as a spot treatment. They dehydrate the plants by breaking down the outer cuticle on the leaf surface. This method is not effective in fighting perennial weeds. Corn gluten meal inhibits the formation of roots in germinating seeds. It also acts as a natural fertilizer for mature plants with established root systems. (See Reference 5)
- Environmental Protection Agency: Lawn Weed Control
- U.S. Department of Agriculture: National Agricultural Library: Should I Purchase Organic Foods?
- Food and Agriculture Organization: Pesticides as Water Pollutants
- Iowa State University: Weed Management for Organic Farmers
- Iowa State University: Department of Horticulture: Corn Meal Gluten Research Page
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