ALTERNATIVE WEED CONTROL IN ARABLE CROPS France Integrated weed management (IWM) is a broad term covering many methods that can be combined and applied in various ways to the crop to constitute an IWM strategy. This persentation shows the example of the french network Desherb’sol and the techniques in five crops: winter wheat, winter oil-seed rape, sunflower, maize and sugar-beet. MODULE C19

Aims of weed mechanical or mixt control : Sustainable use of herbicides Background: reduction of pesticides in France → Grenelle Environment → Basin supply catchment Reducing the cost of herbicides use → 15-25% of operating expenses Sustainable herbicide The technical "plus" → Effect on soil warming    → Interest in the positioning of fertilizers → Enable mineralization INTRODUCTION the advantages of these techniques are into the 3 pillar of sustainable agriculture: environmental and social: political background in France (Ecophyto, Grenelle) and surface water pollution with herbicides economic: cost of herbicides use But this slide open the door on the technical advantages as well:  quality of soil and fertilization

Weed control into the rotation: Agronomic Principles Diversifying crops Take advantage of intercropping to reduce the seed bank Use tillage wisely Stagger planting dates Using the factor “crop competition” By combining these principles the maximum weed control will be facilitated, optimized the use of herbicides and the risk of emergence of resistance limited AGRONOMIC PRINCIPLES Weed control must be reasoned into the rotation : to use all the techniques to minimize the growth of population of some species; to allow the development of the crops without the influence of weeds. 3

Comparison of two weed management Region Burgundy (France) Wheat Weeds: Alopecurus, Bromus, Veronica, Viola, Galium Sowing 3L Tillering Beginning of Stem elongation Ear at 1cm 1 Node T2 Mesosulfuron Iodosulfuron + Propoxycarbazone + florasulame T1 Isoproturon + dff + ioxynil + bromoxynil From 1st of october CHEMICAL 2 to 3 stale seedbed No possibility of mechanical control with winter weather conditions CASE STUDIES Presentation of 5 cases of different crops: wheat, winter rape, maize, sunflower and sugar beet. In each case, the problem weeds in the region are named and routes of conventional chemical weeding and mixed weeding are compared. The examples are for two French regions in the north-east: Burgundy, Champagne: with the mixt weed control, you must to shift the sowing date because you use the stale seed bed technique you can show how less use herbicides (number of treatments, rates,…) WEED MANAGEMENT IN WHEAT Density +10% 2 tillages Shifting the sowing date from the 20th of october T2 Propoxycarbazone + florasulam MIXT

Comparison of two weed management Region Burgundy (France) Oil-seed rape Weeds :Alopecurus, Bromus, Matricaria, Stellaria,Galium, (Geranium) Sowing Cotyledon 1L 4L Rosette T1 Napropamid Clomazone Dimetachlor + quinmerac métazachlor T2 Propyzamid From mid-august CHEMICAL 1 stale seed-bed WEED MANAGEMENT IN OIL-SEED RAPE T1 Napropamid Clomazone Dimetachlor On 1/3 of the soil From early september T2 Propyzamid MIXT Hoeing

Comparison of two weed management Region Burgundy (France) Maize Weeds : Summer grasses, Chenopodium, Amaranthus, Solanum nigrum Semis Emergence 2 L 4 L 5-6 L 8 L Cover-cropping And Tillage T1 Acetochlore + dichlormid CHEMICAL WEED MANAGEMENT IN MAIZE T1 Mesotrione + s-métolachlor On the sowing row MIXT Hoeing

Exemples d’itinéraire technique Region Burgundy (France) Sunflower Weeds : Summer grasses, Chenopodium, Amaranthus, Solanum nigrum Sowing Emergence 4 L Cover-cropping and Tillage T2 Flurochloridone T1 S-métolachlor CHEMICAL WEED MANAGEMENT IN SUNFLOWER T1 Flurochloridone on the sowing row MIXT Hoeing

Comparison of two weed management Region Burgundy (France) Sugar-beet Weeds : Chenopodium, Apiaceae, Sonchus, Cirsium, Mercurialis, CRape volunteers, Matricairia, Amaranthus … Sowing Cotyledon 1L 4L T1 + T2 + T3 + T4 Phenmedipham desmedipham Ethofumesat Metamitron Lenacil T5 Grass killer herbicide (if needed) 40% rate CHEMICAL To control all the weeds emergences WEED MANAGEMENT IN SUGAR-BEET T1 + T2 Phenmedipham desmedipham Ethofumesat Metamitron Lenacil T3 Grass killer herbicide (if needed) 40% rate MIXT Hoeing 2 passages To control only the earlier weeds emergencues Total or localised spray

Pesticides use reduction Treatment Frequency Index 2,17 2,77 Herbicide - 51% 1,77 Herbicide - 45% 1,67 TFI Herbicide Herbicide - 80% 1,33 1,27 Herbicide - 73% 0,96 TFI This slide show the exactly amount of herbicides in the two compared management. You can demonstrate that the reduction is from 45% to 80% by crop. 0,33 0,33 Chemical Mixt Chemical Mixt Chemical Mixt Chemical Mixt Wheat Oil-seed rape Maize Sunflower TFI = Treatment Frequency Index = number of registrared rates sprayed in a field

Agricultural feasibility Rotative hoe Weed harrow Hoeing machine Loamy Clayey SOIL Capped Stony Stage EM 2L 4L 6L EM 2L 4L 6L EM 2L 4L 6L WEEDS Grasses Broadleaves AGRICULTURAL FEASABILITY This slide gives information when you can use mechanical equipment with the type of soil, the stages of weeds and crops. EM = emergence L = leaves Stage EM <2L 4L 6L EM <2L 4L 6L EM <2L 4L 6L CROP Selectiviy Well adapted Adapted Dangerous No

(Total – Operating expenses) (Gross margin – Mechanization expenses) Economical viability Comparison of operating expenses In chemical or mixt management 50 100 150 200 250 300 350 400 450 Chemical Mixt Operating expenses (€/ha) Regulators Insecticides Herbicides Fongicides Fertilization Seeds Intercropping - 43 € - 37 € WHEAT MAIZE Mechanization expenses In chemical or mixt management 180 + 8 € 160 + 26 € 140 120 100 Spraying and fertilization Chemical weed control Mechanization expenses (€/ha) 80 Mechanical weed control Sowing 60 Intercropping 40 20 Chemical Mixt Chemical Mixt WHEAT MAIZE WHEAT MAIZE Chemical Mixt Gross margin (€/ha) (Total – Operating expenses) 558 601 717 754 Net margin (€/ha) (Gross margin – Mechanization expenses) 428 445 564 593 ECONOMIC FEASABILITY It is very important to show the economical results with gross and net margins taking into account the mechanization expenses of the different systems in the different crops. Costs (Burgundy chamber of agriculture / 2007): Sprayer 24m, 1500 liters (15.000€ Taxes non included)  600 ha/year + 10 ha/h = 6,2 € /ha Localised sprayer kit (3600 € TNI) = 8,6 € / ha Weed harrow 12m (7000 € TNI)  140 ha/year + 9,6 ha/h = 9,8 € / ha Rotative hoe 4,7m (9700 € TNI)  200 ha/year + 5 ha/h = 11,8 € / ha Hoeing machine; 6 rows (7000 € TNI)  60 ha/year + 1,8 ha/h = 31,1 €/ha

Other inovative techniques Experimental Direct Drilling Live Mulch Geraniums in early winter (weeds/m²) 20 40 60 80 100 120 140 Deep cultivating Deep + sup Direct drilling NEW SOLUTIONS You can show new experimental solutions to be tested : - direct drilling - drilling under live mulch - drilling with other crops Mixt crops

Conclusion: Response to general principles of IPM Environment: Reduced quantities of herbicides (Part 5) Agronomy Resistance management (part 7) Use of alternative methods (part 4) Combination with preventive methods (part 1) Terms of Success: technical knowledge Economy Margins comparable between chemical and mixt management More advantages if mechanization investment (equipement with large width, gps, ...) More manpower is sometimes needed CONCLUSION You have to show the different IPM principles this technique follows: less herbicides and less resistance use of non-chemical methods but also the odds and sods about economical aspects: mechanization investment is needed sometimes manpower as well