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Definition and Characteristics of Weeds

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Rural Technology

Definition:

Any plant not sown in the field by the farmer and grow where they are not wanted is called a weed. Weeds are like any other crop plants in size, form, morphological and physiological characters but possess the following characteristics on account of which they are considered as enemy of crops.

Characteristics of Weeds:

1) The weeds seed germinate early and the seedlings grow faster. They being hardy compete with the crop plants and deprive them of light, moisture and nutrients. 2) They flower earlier, run to seed in profusion and mature ahead of the crop. They are, therefore, difficult to control and it may be even impossible to eradicate some weeds completely. 3) They are unuseful, unwanted and undesirable. 4) They are harmful to crops, cattle and human-beings. 5) They can survive even under adverse conditions. 6) They are prolific and have a very high reproductive capacity. 7) Viability of seeds remains intact, even if they are buried deep in the soil. 8) The seeds may have special structures like wings, spines, hooks, sticky hairs etc. on account of which they can be easily disseminated over long distance. 9) Many weeds like doob are vegatatively propagated and spread rapidly all over the field even under adverse conditions. Classification of Weeds Weeds may be classified on the basis of:- i) Life cycle ii) Place of occurrence iii) Plant family iv) Dependence on the other hosts v) Soil types The important classification of weeds is on the basis of life cycle. Life cycle:- Weeds are classified according to the time required for the completion of their life cycle. Intext Questions 7.1 Match the followings:- 1) Annual weeds a) Doob 2) Biennial weeds b) More than two years 3) Perennical weeds c) Two season to complete life 4) Vegetative propagation d) One season to complete life cycle


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