Maharashtra Board Class 11 Agriculture Science and Technology Chapter 10 Weed Management PDF Download

Weed Management

Farmers sow the seed in field and take care to obtain produce from that. The plant grown in the field (cultivated plants) by farmer are called as crop. Some plants grow without putting any seed and competing to the main crops for nutrient, water and space that makes heavy loss of crop yield, such plant are considered enemy of crop which causes huge loss of yield and favour other enemies as pest, diseases, wild animals, etc. These plant enemies are called weeds.

Weeds are unwanted, useless, prolific, competitive and often harmful to the human beings. Weeds are undesirable as they not only compete with crop for nutrients, moisture, space and sunlight but also interfere with agricultural operations (labour, tillage). It also affect the yield and quality of farm produce. Weed seed may get mixed with main crop seed. These weed plants are required to be uprooted before flowering stage. Therefore management of weeds at right time is necessary.

10.1 Definition Of Weed

The most common definitions of weeds are:

Weed is a plant growing where it is not desired.

Any plant not sown in the field by the farmer and which is out of place is known as weed.

Weed is a noxious, unwanted, undesirable plant in the field.

Teacher's Note

Weeds are plants that grow where we do not want them. Just like unwanted guests in your home, weeds are unwanted plants in the farm that damage the crops.

Exam Trick

Remember: Weed = Not wanted by farmer. If a plant grows without the farmer planting it, it is a weed. Like a guest who comes without being invited!

Points to Remember

Weeds are unwanted plants that grow in the field.
Weeds compete with crops for water, food, and sunlight.
Weeds grow faster and stronger than crops.
Weeds can reduce the amount of crops we get from the field.
We must remove weeds before they make seeds.

10.2 Characteristics Of Weed

They are unwanted and undesirable.

Weeds are harmful to crop, cattle and human beings.

The weed seed germinate early and grow very fast.

They flower earlier, produce more quantity of seed and mature earlier or late than crop and their separation become difficult.

They being hardy, compete with crop plants for nutrients, moisture, space, sunlight and reduce the crop yield.

They can thrive even under adverse conditions of soil, climate and biotic stress.

Viability of weed seed remain intact, even they are buried deep into the soil and passes through digestive track of the animals.

Weeds are prolific with abundant seed production capacity. For example: Striga, Hazardana, Piwla Dhotra.

Weed seed have special structure like wings, spines, sticky, hairy, light weight, free flowing and hooks, etc. on account of which they can be easily spread.

Some weeds are propagated vegetatively for example: Doob, Kans, Lavala, etc.

Some weed seed are very similar to crop seed and therefore their separation become very difficult. For example: Mustard seed with seed of Piwla Dhotra.

They are persistent and resistant to control and eradication.

Some weeds have deep roots they store food in their rhizomes and reappear every year.

Some weeds have similar morphological characters like crops therefore escaped from weed control. For example: Wild rice, wild oat.

Some weed seed have long dormancy period and have a hard seed coat and hence not loose viability.

Teacher's Note

Weeds have many special powers to grow and spread. Some weeds can float on water and spread far away, just like how seeds can travel in the wind.

Exam Trick

Remember: Weeds are "Super Plants". They grow faster, make more seeds, and survive in bad conditions better than normal crops!

Points to Remember

Weeds grow very fast and make many seeds.
Weed seeds can travel by wind, water, and animals.
Some weeds have special hooks or spines to stick to animals.
Weeds can live in very bad soil conditions.
Weeds look similar to crops so we cannot always find them.

10.3 Classification Of Weeds

10.3.1 According To Life Cycle

Annual weeds: These weeds grow and mature within a season.

Kharif season weeds: They appear with the onset of monsoon (June / July) and complete their life cycle when rainy season is over (Oct. / Nov.) for example: Cocks comb, math, dudhi, hazardana, parthenium, chimanchara, etc.

Rabi season weeds: Weeds grow during winter season and finish their seed production before summer starts. For example: bathua, ghol, vasantvel, etc.

Summer season weeds: Summer season weeds complete their life cycle during summer season (Feb / May) for example: Solanum nigrum (kamuni), Argemone mexicana.

Multiseason weeds: They occur almost at any time of the year. For example: Eleusine indica (Goose grass) Phylanthus niruri (Bhuiaonla).

Biennial weeds: These weeds live for two seasons. They complete vegetative growth in first season and produce flowers and seeds in the next season. These are mostly found in temperate climate. For example: Jangli gobhi, wild carrot, wild onion, wild brinjal.

Perennial weeds: They require more than two years to complete their life cycle. For example: nutgrass, hariyali, johnson grass, wild ber, ghaneri, kans, motha or lavala.

10.3.2 According To Place Of Occurrence

Weeds of cropped lands: For example: dudhi, chandvel, vasantvel, cocks comb, bathua, etc.

Weeds of pastures and grazing lands: For example: parthenium, hulhul, hariyali, etc.

Weeds along water channel: For example: jalkumbhi, pandhari phuli, maka, ekdandi (Jakhamjodi), etc.

Weeds along rail and roadside: For example: tarota, gokhru, parthenium, chubh kata, etc.

Weeds of waste land: For example: wild ber, rui, babhul, parthenium, etc.

Weeds of lawns and orchards: For example: Cannabis sativa, ambooshi, ghol, etc.

Weeds of forest lands: For example: Lantana camara (ghaneri) tantani, chillari.

10.3.3 According To Plant Family

Gramineae: For example: hariyali, kans or kunda, chiman chara, etc.

Leguminosae: For example: lajalu, shewara, senji, tarota, takala, etc.

Solanaceae: For example: wild brinjal, kateli or kateringani, etc.

Euphorbiaceae: For example: All types of dudhi (Euphorbia spp.)

Liliaceae: For example: wild onion.

Convolvulaceae: For example: chandvel, hirankuri, undirkani, etc.

Compositeae or asteraceae: For example: parthenium, maka osadi, pandhari phuli, pohli.

Teacher's Note

Different weeds grow in different places and in different seasons. Some weeds like the wet areas, while others like dry areas. Understanding where weeds grow helps us remove them better.

Exam Trick

Remember: Weeds are "location specific". Different weeds grow in different places. Like parthenium grows on roads, but lavala grows in wet places!

Points to Remember

Weeds are classified by when they grow (annual, biennial, perennial).
Weeds are classified by where they grow (field, pasture, water, road).
Weeds are classified by which plant family they belong to.
Annual weeds complete their life in one season.
Perennial weeds take more than two years to complete their life.

This is a preview of the first 3 pages. To get the complete book, click below.