Differentiate between preventive and curative method of weed control.
Answers
Answer:
Preventive methods include crop rotation, cover crops (when used as green manures or dead mulches), tillage systems, seed bed preparation, soil solarization, management of drainage and irrigation systems and of crop residues.
Answer:
Avoid using crop that are infested with weed seeds i.e., use of clean seeds for sowing. Weed free crop seeds may be produced by following the pre-cautionary measures.
• Separating crop seeds from admixture of crop and weed seeds using physical differences like size, shape, colour, weight/texture and electrical properties.
• Using air-screen cleaners and specific gravity separators, which differentiate seeds based on seed size, shape, surface area and specific gravity.
• Through means of seed certification we can get certified seeds and can be used safely because the certified seeds contain no contaminant weed seeds.
• Weed laws are helpful in reducing the spread of weed species and in the use of well adapted high quality seeds. They help in protecting the farmers from using mislabeled or contaminated seed and legally prohibiting seeds of noxious weeds from entering the country. (Weed Control)
• Quarantine laws enforce isolation of an area in which a severe weed has become established and prevent the movement of the weed into an uninfected area.
• Use of pre-emergence herbicides also helpful in prevention because herbicides will not allow the germination of weeds.
• Avoid feeding screenings and other material containing weed seeds to the farm animals.
• Avoid adding weeds to the manure pits.
• Avoid the use of raw dung as manure.
• Pull out seedlings in nurseries carefully without weed seedlings.
• Clean the farm machinery thoroughly before moving it from one field to another. This is particularly important for seed drills.
• Avoid the use of gravel sand and soil from weed-infested.
• Inspect nursery stock for the presence of weed seedlings, tubers, rhizomes, etc.
• Keep irrigation channels, fence-lines, bunds un-cropped areas and roads clean.
• Use vigilance. Inspect your farm frequently for any strange looking weed seedlings. Destroy such patches of a new weed by digging deep and burning the weed along with its roots. Sterilize the spot with suitable chemical.
• Quarantine regulations are available in almost all countries to deny the entry of weed seeds and other propagules into a country through airports and shipyards.
Explanation: