Weeds are the plants, which develop where they are not wanted. Weeds can be alluded to as plants out of place. Weeds compete with crops for water, soil nutrients, light, and space & hence decrease crop yields.
Weeds regularly produce huge numbers of seeds, helping their spread. They are frequently great at surviving and replicating in disturbing situations and are routinely the primary species to colonize and overwhelm in these conditions. A weed can be an exotic species or a local species that colonize & holds on in an environment in which it did not already exist. Weeds can occupy all situations; from our towns and cities through to our seas, deserts & alpine areas.
It is the method of minimizing the weed populace and their development underneath the level of economic harm to the crop with the least environmental pollution.Weeds can be managed by embracing any appropriate strategy of weed control and if required by combining two or more strategies of weed control.
Why weeds are a problem?
Weeds compete with trees for dampness and supplements. A few weeds are also substituted hosts of maladies, nematodes, r creepy crawlies, e.g. dark spoil parasites, phytoplasmas, root-lesion nematodes, discolored plant bug (e.g. on chickweed). Interference from weeds may moreover cause labor wasteful aspects e.g. tall weeds at harvest, inconvenience from hypersensitivities (e.g. ragweed), or skin irritations from poison ivy, stinging brambles or thorns.
Cycles of weeds
- Annual Weed
Grow and bloom in one year. A few weeds in orchards are winter annuals, i.e. they start their growth within the fall, shaping a rosette, and blossom the following spring or summer.
- Biennial Weed
Have a two-year life cycle, producing leaves within the first year and blossoming within the second year.
Annual and biennial weeds compete for supplements and water as they develop beneath trees. After they blossom, they die. In any case, their seeds may cause repeating issues for a few years by shaping a soil seed bank.
- Perennial weeds
Live for numerous years, and for the most part, establish from different sorts of root systems, and numerous too spread by seeds. They ordinarily bloom each year, extending their root system and spreading by both strategies through plantations. Perennial weeds can be exceptionally competitive, particularly if they develop in thick patches.
Advantages of Weed
- Weeds add organic matter and nutrients to soil
Numerous weeds have rich verdant growth and when buried within the soil as green fertilizer include a significant amount of natural matter and plant nutrients. Weeds include almost 5 to 15 tons of green matter per hectare depending upon weed species and their growth.
- Weeds check wind, soil and water
Weeds growing on desert lands, squander lands, and messy areas lower wind and water disintegration and also offer assistance for the protection of the environment.
- Weeds when furrowing beneath, add supplements, natural matter.
- Useful as fodder for castles and vegetables by human beings.
- Have restorative value, Leucas Aspera is utilized against snake bite, oil of satyanashi seed is valuable against skin illnesses, nuts of lavala are utilized in making fragrances (Incense sticks).
- Weeds can too be important indicators of developing conditions in a field, for example of water levels, compaction, and pH.
- Have economic significance e.g.: Saccharum spp utilized for making thatches.
- Reclamation of alkali lands.
- Serve as ornamental plants.
- Used for fencing
- Used as mulch to check the evaporation losses of water from the soil.
- Used as green manuring & composting.
- Fix barometrical ‘N’ (Blue-green green growth, Tarota, Unhali, etc.)
Methods of Weed Control
- Preventive Weed Control
This management strategy points to avoid defilement of the planting fabric and cultivated regions. It involves:
- Buying high-quality weed-free seeds
- Washing equipment
- Checking livestock’s fur and legs
- Screening water system waters for weed seed transportation
- Use of thoroughly spoiled compost and excrement to anticipate seed germination.
- Cultural Weed Control
It guarantees field conditions that are less favorable for non-crops to develop. The given management approach includes
- Planting high-adaptive and competitive species
- Selecting enormous seeds that are likely to create solid and dynamic plants
- Crop rotation
- Field following
- Use of cover crops
- Reduction of space between rows
- Shallow seeding (in this way, crops can develop speedier than other herbs)
- Planting local species that adjust to the characteristic environment and compete with weeds easier.
- Mechanical Weed Control
This management strategy proposes wrecking undesirable plants with cultivating equipment or physically. This aspect of management utilizes:
- Manual pulling (hand removal)
- Covering space between rows (for example, with straw)
- Robotic weeding machines
- Weed seed destructors
- Haymaking before weeds burst with seeds.
- Biological Weed Control
It utilizes plant adversaries in their habitats. Hence, sheep, tansy insect creepy crawlies, and cinnabar moths crush tansy ragwort. Grazing is another example of the management technique. Biological control moreover incorporates putting pathogen life forms like microbes, organisms that attack certain species. They are diverse and damage separate parts (leaves, stems, seeds, roots). Biological weed management was effectively undertaken in north-east Australia within the early 20th century when the cactoblastis moth battled the thorny pear with other cases to follow.