Weeds are unwanted plants that obstruct the use of land and water resources, reducing food productivity and negatively impacting human welfare. Weed is a plant that originates in a natural environment and evolves as an interfering associate with the desired plant and activities in response to imposed and natural surroundings.
Weed is also said to be a plant that grows in the wrong place at the wrong time. They are undesirable, not useful, tenacious, and prolific, effectively competing with space, nutrients, sunlight, and water with beneficial and desirable crop plants, interfering with agricultural operations and lowering output and quality of produce.
Harmful Effects of Weed
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Weeds have a significant negative impact on agricultural output. In most affluent countries, weeds are projected to inflict a 5% loss in agricultural production and a 25% loss in the least developed countries. Weeds cause larger yield losses than pests and diseases in India. Weed-caused yield losses differ by crop. Weeds pose a significant threat to every crop. Because of their quicker rate of development in the early stages of crop growth, most of these weeds are self-sown and provide competition. Weed infestation reduces yields by up to 50% in some crops.
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Some weeds produce hazardous chemical inhibitors into the soil, which can injure crop plants, humans, and cattle.
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Weeds compete with crops for resources such as water, nutrients, light, and space, lowering agricultural yields. Weeds can deprive crops of 47 percent nitrogen, 42 percent phosphorus, 50 percent potassium, 39 percent calcium, and 24 percent magnesium, according to estimates. Weeds can also serve as an alternative host for insects, pests, diseases, and other microorganisms.
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Weeds degrade the quality of agricultural products that can be sold. Contamination with weed seeds such as Datura sp., Argemone sp., Brassica sp., and others is damaging to human health, and weed seeds in produce can occasionally produce an unpleasant odor.
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Weeds not only lower productivity but also disrupts agricultural operations. Weeds make mechanical sowing difficult to harvest crops, resulting in additional costs for labor, equipment, and chemicals to remove them.
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Weeds in the aquatic environment obstruct water flow in canals, water transport systems, and drainage systems, making navigation difficult. Aquatic weeds pollute the water by deoxygenating it and killing the fish that live in it.
Benefits of weeds
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Despite all of the problems that weeds create, they can have certain useful features, especially when present in low densities. These elements should be incorporated into the farming system, albeit organic management may be more difficult than chemical-based approaches.
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Assisting in the conservation of soil moisture and the prevention of erosion. Weeds help to preserve nutrients by reducing the quantity of bare soil exposed, especially nitrogen, which could be leached away, especially on light soils.
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The presence of weed cover could help increase the effectiveness of biological pest control and reduce pest damage.
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Weeds can also be useful indicators of field growing conditions, such as water levels, compaction, and pH.
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Weeds can be a valuable food source for wildlife, particularly birds. Over the last few decades, bird populations have been dropping on farms, and leaving weeds as a resource has been demonstrated to help restore bird populations.
