weed management.pptx for agriculture studies

Weed management is a combination of the techniques of prevention, control, and eradication to manage weeds in a crop, cropping system, or environment. Weed managers recognize that a field's or area's cropping history, the grower's management objectives, available technology, financial resources, and a host of other factors must be considered before appropriate management decisions can be made. Complete weed control in a crop may be the best decision in some cases, but one should not assume that it will always be the most desirable goal. Maintenance of a weed population at some low level in a cropping system may be the most easily achieved, financially wise, and environmentally desirable goal.

Weed management is a challenging task especially during the rainy season due to the emergence of weeds in flushes, the unpredictability of rains, the nonworkable soil conditions, and the nonavailability of timely labor. Considering the diversity of the weed problem, no single method of weed control, whether manual, mechanical, or chemical would be sufficient to provide season-long weed control under all situations. An integrated weed management system as a part of an integrated crop management practice would be an effective, economical, and ecofriendly approach for weed management in millets. A combination of preemergence herbicides with manual or mechanical weeding or intercropping of smothering crops like cowpea would be required for effective weed management in millets. Sequential application of pre and postemergence herbicides may provide broad-spectrum weed control. Considering the several advantages of using the genetically modified herbicide-tolerant corn, it is worthwhile exploring the possibility of herbicide-tolerant grain sorghum.

Weed management is a challenging task especially during the rainy season due to the emergence of weeds in flushes, the unpredictability of rains, the nonworkable soil conditions, and the nonavailability of timely labor. Considering the diversity of the weed problem, no single method of weed control, whether manual, mechanical, or chemical would be sufficient to provide season-long weed control under all situations. An integrated weed management system as a part of an integrated crop management practice would be an effective, economical, and ecofriendly approach for weed management in millets. A combination of preemergence herbicides with manual or mechanical weeding or intercropping of smothering crops like cowpea would be required for effective weed management in millets. Sequential application of pre and postemergence herbicides may provide broad-spectrum weed control. Considering the several advantages of using the genetically modified herbicide-tolerant corn, it is worthwhile exploring the possibility of herbicide-tolerant grain sorghum.Weed control, an old practice, is a process of reducing weed growth to an acceptable level. Weed management includes the dictionary sense of management—“taking charge of and directi

1. Weed control Methods – Physical,Chemical , Biological, Cultural,Allopathic Methods

2. Weeds A weed is a plant growing where it is not wanted Unwanted plant A plant out of place A plant that is extremely noxious,useless , unwanted or poisonous

3. Weed problems Weeds deplete crops environment of nutrients,water and light Crop yield are reduced considerably by weeds Weeds interfere in agricultural practices Quality of produce reduced by weed infestation

4. Weed Control Methods Weed control methods grouped into Physical Cultural Biological Chemical Allopathy

5. Physical weed control Physical force either manual,animal or mechanical power is used to pull out or kill weeds Depending on crops and weed following methods are used

6. Hand weeding Weeds are removed and collected from crop field by hand Pulling out weeds by using small tools

7. Hand hoeing The entire surface soil is dug to a shallow depth with help of Hand hoes This method is used for irrigated upland crops like finger millet,pearl millet,onion

8. Digging Weeds are removed by Digging up to deeper layers Very useful in case of perennial weeds

9. Mowing Cutting of weeds to ground level Common Mowing tools are sickle,scythe and lawn mower

10. Cutting Weeds are cut above the ground surface leaving stubble Cutting is done with help of axes and saws

11. Burning and flaming Cheapest method of eliminating mature unwanted weeds Also used to dispose off heaped weeds

12. Mulches Mulches when applied on soil surface,do not allow weeds to germinate or to grow as light does not reach the soil

13. Merits of physical weed control Oldest, effective and economical method Large area can be covered in shorter time Safe method for environment Deep rooted plants controlled effectively

14. Demerits of physical weed control Labour consuming Possibility of damaging crops Ideal and optimum specific condition

15. Cultural weed control Cultural weed control refers to any technique that involve maintaining field condition. Several Cultural practices like tillage,planting,fertilizer application,irrigations etc

16. Field preparation Field has to be kept weeds free Flowering of weeds should not be allowed Helps to prevention of build up of weed seed population

17. Summer tillage Summer ploughing is defined as ploughing the field across the slope during hot summer using specialized tools. Effective Cultural method to check the growth of perennial weeds

18. Crop rotation Crop rotation is a practice of planting different crops subsequently in the same plot of land to improve soil health Crop rotation eliminate or atleast reduce difficult weeds problems

19. Growing of intercrops Intercropping is a term used to refer growing two or more crops in close proximity. Inter cropping suppresses weeds better than sole cropping

20. Solarisation Method of utilization of solar energy for the desiccation of weeds Soil temperature is further raised by 5 to 10°c by covering a pre soaked fallow field with thin transparent plastic sheet

21. Blind tillage It refers to tillage done after seeding or planting the crop early stages of growth Tillage of the soil after sowing a Crop before the crop plants emerge

22. Merits of cultural methods Low cost Easy to adopt No residual problem No damage for crops Technical skills not involved

23. Demerits of cultural methods Practical difficulty in adoption Weeds are kept under suppressed conditions Perennial and problematic weeds cannot be controlled

24. Biological control of weeds Biological control of weeds involves use of living organism Such as insects, herbivores fish,animals,diseased organism

25. Examples of biological weed control Fish: common crap and Chinese carp control aquatic weeds Mammals: sea cow is very effective in controlling water hyacinth Snales:merisa sp. and other fresh water scales feed on submerged weeds like contain and algea

26. Fungi: water hyacinth can be controlled by rhizoctinia blight Mites: a spider mites found to be useful in controlling prickly pear Plants: copper sown in between sorghum rows effectively reduces the growth of weeds

27. Examples of classical biocontrol of weeds Lantana Camara Prickly pear Alligator weed Water hyacinth Salvinia molessta

28. Chemical weed control methods Chemicals that are used to kill plants ore weeds are called herbicides Methods of application are soil application and foliar application

29. Common examples of chemicals used to control weeds inforages are 2,4-DB,bromoxynil and paraquat . Soil application:Herbicides are usually applied to soil surface to form a uniform herbicide layer Eg : Triazines,urea and anilide Soil incorparation:some herbicides are applied to Soil surface and incorporated into the soil either by tillage or irrigation Eg:aniline,carbamate

30. Blanket application:Application of Herbicides over the entire leaf area.Selective Herbicides are applied by this method Directed application:Herbicides are applied directly to weeds between crop rows,avoiding the crop foliage. Spot application:Herbicides are applied or poured on small patches of weeds,leaving the relatively weed free patches untreated

31. Allelopathy in weed management The phenomenon of allelopathy refers to chemical interactions between all types of plants.In this process the chemical exudates or leaches released from the plant parts can inhibit the growth of a neighboring one.

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