The growth of unwanted plants called weeds in the farms can be disturbing for an organic farmer. But it is a fact of nature that weeds grow and affect the overall health and yield of crops. It demands the highest labor inputs in organic farming.
The weeds damage the crops in several ways:
- These unwanted plants outcompete the crops for water, sunlight, and nutrients supply, affecting the overall yield of the crop.
- Certain weeds secrete toxic chemicals that can affect the seed germination and growth of new plants.
- Some weed roots bind with undercutting root tools and interfere during harvesting crops.
- These useless plants reproduce in cropping season and produce abundant seeds due to highly fertile soil. That's why they may be difficult to control.
- Prevent weeds growth: Weed prevention has more importance in organic farming than its control. For this purpose, improve the soil tilth, water percolation, and aeration. The removal of weeds is easy in well-aerated soil. Avoid weed seed transportation from infested neighbor lands. Make sure to clean the tools and farm equipment before using them on the farm. The manure of imported animals contains viable weed seeds. Therefore, aerobically compost the manure by maintaining a temperature of more than 55 degrees Celcius for 15 days. This process destroys all the viable seeds in the manure.
- Apply Crop rotation techniques: Plant weed suppressive cover crops in your rotation to minimize weed pressure. For this, grow summer-loving cover crops such as sudangrass (Sorghum bicolor), Buckwheat(Fagopyrum esculentum). Sesbania(Sesbania macrocarpa), Annual ryegrass(Lolium multiflorum). These grasses cast a shade over the weeds and prevent their reproduction. Another option is to grow crops that can compete well with weeds. Such crops include potatoes, corn, and winter squash.
- Flame weeding techniques: Flame weeding is a process in which flame is used to destroy the weeds. Flame weeders are available as handheld wands and man-powered pushcarts and propane is used in them as a fuel source. Flame weeding is done on ready-to-grow land before irrigation. It kills all the newly emerging weeds. This technique is effective but a bit expensive to invest in a tractor-mounted flame weeder.
- Use careful planting and cultivation techniques: Grow large-seeded crops such as squash, beans, and corn as they can mature without irrigation. These crops inhibit weed growth by providing shade over them. Also, the weed seeds fail to germinate in the absence of water. Besides, keep the tractor-mounted weed cultivators shallow. This will prevent bringing up deep-buried weed seeds. Make sure to plant the crops in uniformly spaced straight lines. It will reduce the cost of hand weeding by allowing close mechanical cultivation.
- Add weed suppressive mulch to the soil: Mulching is the most successful practice of weed control in organic farming. In this technique, the layer of soil is covered with either organic mulch such as straw, dried leaves, or farm wastes or inorganic mulch such as a plastic sheet. It blocks the sunlight and prevents seed-soil contact.