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Organic weed-management
This document discusses weed management strategies for various crops in different Indian states. It provides details on the most common weeds associated with rice in Jharkhand, potato in Meghalaya, sugarcane in Uttar Pradesh, and pineapple in Nagaland. For each crop and state combination, the document outlines the key weeds, their impact on yields if uncontrolled, and recommended cultural, biological, and mechanical control practices. Finally, the conclusion emphasizes that an integrated approach using multiple control strategies together is most effective for weed management.
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Organic weed-management
- 1. SUBMITTED TO: Prof. (Dr.)THOMAS ABRAHAM DEPARTMENT OF AGRONOMY ALLAHABAD SCHOOL OF AGRICULTURE SUBMITTED BY: GROUP NO # 13
- 2. What is WEED….???? “Plantwhose virtues are yet to be discovered” “A plant out of place” Weeds are unwanted or undesirable plants that compete with crops for water, soil nutrients, light and space (i.e. CO2) and thus reduce crop yields. Weeds account for 33% loss in agriculture alone.(Jethro Tull, 1731)
- 3. Successful Management Requires Multipleapproaches Continual effort Knowledge of the biology of weeds species Reproduction, lifecycle, establishment annual, perennial, wandering perennial, broadleaf, grass. Weed : Top issues for Organic Farmers
- 4. Principles Involved: Eco Friendly:- i.e. it should cause no harm to our environment. Break the survival mechanism of the weed in soil. Easily acceptable by the progressive farmers. Crop husbandry ( Crop Rotation, Mulching etc.)
- 5. Multiple Prevention and EliminationStrategies (Practices): Cultural Biological Physical Mechanical “Many hammers approach.” Liebman and Gallandt, 1997
- 6. Cultural Strategies Buy qualitycrop seed with low/no weed seeds present. Do not allow weeds to form seed. Improve crop competitiveness Improve soil tilth, aeration, and fertility to optimize crop growth Increase crop density through narrow row spacing and increased seeding rate Use transplants, rather than seed, when possible
- 7. Cultural Practices Reduce weednumbers Mulch (wood chips, mow and blow, paper, living, plastic, etc) Use weed-suppressive cover crops Quick germinating, high biomass Field with high weed pressure may warrant full year of cover cropping and fallow to reduce weeds Crop rotations altering narrowly spaced crops with closely spaced crops, shallow rooted/deep rooted crops, cold/warm season crops Intercrop Clover underseeded in sweetcorn.
- 8.
- 9. Cover Crops Field pea-oat- mustardcover crop Red Clover
- 10. Crop Rotations • Weedstend to infest crops with similar life cycles. • Change crop ecology: shallow/deep roots, cold/warm season, row/drilled crops, foliage density, and heavy/light feeders. Change cultural practices: cultivation, mowing, fertilization, herbicide application, and planting/harvest dates
- 11. Biological Control Practices Insects:may consume large numbers of weed seeds or feeding injury to plant or vector virus Phyllocoptes fructiphilus has been shown to transmit rose rosette disease on young fast growing roses Selective grazing Sheep: clean fields after harvest Weeder geese: useful against grass weeds and in perennial systems Biofumigation Use of Brassica species (canola, Indian mustard) as cover crop or in rotation May be incorporated or left as residue Brassicas produce glucosinolates, which may by converted to cyanate compounds during decomposition. Sustainable Vegetable Production from Start-Up to Market, Grubinger, 1999
- 12. Allelopathy Allelopathy is thedirect or indirect chemical effect of one plant on the germination, growth or development of neighboring plants. Species of both crops and weeds exhibit this ability. Allelopathic crops include barley, rye, annual ryegrass, buckwheat, oats, sorghum, sudan sorghum hybrids, alfalfa, wheat, red clover, and sunflower. The alleopathic effect can be used to an advantage when oats are sown with a new planting of alfalfa.
- 13. Physical and Mechanical Practices Mowing Preventsseeding Depletes storage reserves Better control for broadleaves Soil solarization Effective control of winter annuals Limited control of perennials Cost prohibitive on large acreages Avoid tillage deeper than 3” after solarization Hand weeding Cultivation ( done with cultivators) Flaming
- 14. Flaming Intense heat searsthe leaf, causing the cell sap to expand and disrupt cell walls seedlings are most susceptible Broadleaf weeds are more susceptible than grasses May be used in wet soil conditions Sustainable Vegetable Production from Start-Up to Market, Grubinger, 1999
- 15. Crop Map OfJharkhand:
- 16. Weed Management ofRICE ( Major crop ) In Jharkhand. Few weed species are Echinochola crus-galli Echinochloa colona Eclipta alba Monochoria vaginalis Cynodon dactylon Cyperus iria Cyperus difformis Cyperus rotundus If these weeds are not controlled from very beginning the reduction in rice yield may be as high as 12-98%. Critical Period : 30 t0 70 DAS
- 17. Control: Cultural control : Keepinga layer of water (7 cm -15cm) on rice is said to suppress germination of weeds completely. Biological control : Very little is known about natural enemies of this sedge; the fungi, Corticum sasaki , and the nematode Meloidogyne graminicola, may be considered for biological control. Mechanical Control: Hand picking is the most commonly used process practiced for weed management in Jharkhand.
- 18. Weed Management ofPOTATO( Major crop ) In Meghalaya. Most common weed associated are: Witchgrass-Panicum capillare Dense hairs cover the leaf blades on both sides and the sheath Leaves are rolled in the bud and lack auricles Leaves have a white mid-vein Its is a nuisance in lawns and gardens It has a fibrous root system Mature plants are 1 to 2’ tall A.K.A. ‘ticklegrass’
- 19. Control: Prevention:Learn to identifyplants; start monitoring early in the season. Cultural Weed Control: Plant competitive grass or other cover crops. Witchgrass does not compete well with perennial grasses. Mechanical Weed Control Cultivation or mowing before seed develops will control this plant. Witchgrass can also be hand pulled. Biological Control : No known biological control in our area.
- 20. Weed Management ofSUGARCANE ( Major crop ) In Uttar Pradesh. Most common weeds associated are: Sorghum halepense Cyperus rotundus Eleusine indica Saccharum spontaneum Digera arvensis Eclipta alba Cynodon dactylon If these weeds are not controlled from very beginning the reduction in sugarcane yield may be as high as 10-70%. Critical period for weed competition is 4 months after sowing.
- 21. Control: Cultural Weed Control: Selection of cultivars that have quick canopy closure. Seed cane from clean fields. Trash mulch at 45 DAP @ 7-10 t/ha,10 cm thick is effective against many weeds. Mechanical Weed Control Plant cane-scratchers are used over the top of the cane and tines are removed as the can gets larger. Ratoon cane-disk cultivators are used for weed control in row middles. Biological Control : Not practiced in Uttar Pradesh.
- 22. Weed Management ofPINEAPPLE ( Major crop ) In Nagaland Matricaria matricarioides ( Pineapple weed ): the most common associated weed. Plant stems grow erect up to 1’ tall Heads are cone-shaped and a yellowish green colour with each head surrounded by overlapping bracts with no ray petals Crushed heads give off an odour likened to pineapple. An annual plant reproducing by seeds It is a nuisance in lawns and gardens and is also found in croplands and along roadsides.
- 23. Control: Prevention – Learnto identify plants; start monitoring early in the season Biological – No known biological control in our area Cultural – One hand weeding in May/June. For the treatment involving mulching, non-decomposed coffee husk was uniformly applied at a rate of 20 tons ha- 1 as per the schedule & mulched treatments significantly out- yielded treatments without mulch and the clean weeding with 100% weed control efficiency.
- 24. Conclusion Using multiple approaches(“many hammers”) to manage weeds will yield greater impact than relying on a few practices. Develop a weed management strategy that is designed for the needs of your farm. Although weeds can serve as host plants for pests, they can also serve as hosts to
- 25. Conclusion Today, however, withthe increase in organic farming and the decrease in the use of herbicides, breeding for weed suppression has become a higher priority. Instead of eradicating weeds, farmers especially organic farmers-- are learning to manage weeds.
- 26.
Editor's Notes
- #4 Weed management is a top issue for most organic growers. It requires continual effort using multiple approaches we’ll cover in this presentation. Biological knowledge of the weed species working with can be essential for success. Knowing what type of weed it is, how it reproduces and it most vulnerable period are critical information to managing the species. The Cornell University organic weed database is a useful resource that provides this type of information as well as management practices for specific weeds.
- #6 Employing various strategies or “many hammers” are most effective for maintaining adequate weed control. These include cultural, mechanical, biological and chemical practices. Liebman and Gallandt. 2006. Many little hammers: ecological approaches for management of crop-weed interactios. In L.E. Jackson, 3d., Ecology in Agriculture, pp 291-343. Academic Press, San Diego CA
- #8 Weed article
- #10 A good resource for cover crops: Managing Cover Crops Profitably, 3rd ed. SARE www.sare.org/publications/covercrops/covercrops.pdf crops profitably. 3rd ed. SARE
- #12 Biocontrol is specific to the species and works well for infestations of a particular weed and typically in situations where immediate results are not necessary. Biocontrol mechanisms usually take time for maximum effectiveness. Phyllocoptes fructiphilus has been shown to transmit rose rosette disease on young fast growing roses
- #14 Keys to good solarization: work up soil to an even level surface removing big clods and rocks; lay thin plastic sheeting <3mm as close to the ground as possible, burying edges of plastic; use irrigation – wet soil conducts heat better than dry soil, field should remain at 70% field capacity; leave in place for 4-8 weeks; avoid anything more than shallow tilling to avoid bringing up weed seeds from lower depths that were not killed by the heat.
- #15 Sustainable Vegetable Production from Start-Up to Market, Grubinger 1999, NRAES 104