Classification of weeds

 Classification of weeds

                  Out of 2,50,000 species, weeds constitute about 250 species which are prominent in agricultural and non-agricultural system. Under world conditions about 30,000 species is grouped as weeds.

                 Classification of weeds based on -

1. Life span

2. Ecological affinities

3. Place of occurrence

4. Origin

5. Soil pH

6. Specificity

7. Morphology

8. Cotyledon number

9. Soil type (edaphic)

1 Based on life span :-

a) Annual weeds - Weeds that live only for a year and complete their life cycle in that year. Ex. Commelina benghalensis, Boerhavia erecta Chenopodium album 

b) Biennial weeds -  It completes the vegetative growth in the first season, flower and set seeds in the succeeding season and then dies. Ex. Alteramanthera echinata, Daucus carota 

c) Perennial weeds - They live for more than two years and may live almost indefinitely. Ex. Sonchus arvensis, Phleum pratense

2. Based on ecological affinities :-

a) Wetland weeds - They are tender annuals with semiaquatic habitate Ex. Ammania baccifera, Eclipta alba

b) Garden land weeds - These  weeds neither require large quantities of water like wetland weeds nor can they successfully with stand extreme drought as dry land weeds. Ex. Taianthema portulacastum

c) Dry land weed - These are usually hardly plants with deep root system. Ex. Tribulus terrestris