Resource effective control of Elymus repens

Preliminary results show that there is room for improvement within existing control methods of couch grass (Elymus repens (L.) Gould). It may be possible to reduce the number of stubble cultivations during autumn by timing the treatment, and to reduce the cultivation depth by using a goose foot cultivator (5 cm) instead of a disc cultivator (10 cm), without sacrificing couch grass control efficiency. The first year of the experiment, the use of a goose foot cultivator resulted in less nitrogen leaching than cultivation by disc. A reduced number of stubble cultivations potentially reduces nutrient loss, fuel consumption and the workload of the farmer. Our experiments with cover crops to control couch grass in cereals has yet to prove significant effects on couch grass control, but cover crops combined with goose foot hoeing did reduce nitrogen leaching by more than a third compared to cultivation by disc. Further data is necessary to see if the system can be used to effectively control couch grass without significant yield losses. Regardless, it can reduce nitrogen leaching and potentially provide other ecosystem services, e.g. control weeds other than couch grass

Klippträda för att ersätta svartträda

Jordbearbetning är en effektiv kontrollmetod mot perenna ogräs, såsom kvickrot (Elymus repens L.), delvis på grund av att bearbetningen sönderdelar ogräsens underjordiska lagringsorgan (rhizom). Jordbearbetning ökar dock risken för näringsläckage, och det är svårt att kombinera jordbearbetning med en växande gröda. I denna studie använde vi oss av en prototyp med vertikala diskar för att fragmentera kvickrotens rhizomer med minimal störning av jord och gröda. Målet var att utveckla en metod för kvickrotskontroll i gräs-klövergrödor med en kombination av rhizomfragmentering och putsning. Experimenten utfördes 2014 och 2015 i Uppsala, med rhizomfragmentering utförd innan sådd (TRF), i den växande grödan (SRF) eller både och (TRF + SRF). Rhizomfragmenteringen kombinerades med upprepad putsning och tre vallgrödor (vitklöver, italienskt rajgräs eller en blandning av båda) samt kontroll. Resultaten visar att i gräs-klövergrödan minskade rhizomfragmenteringen vikten av kvickrotsrhizom, ökade mängden italienskt rajgräs och det fanns en tendens till ökad mängd vitklöver. TRF och SRF hade liknande effekt på kvickrotsrhizomvikten, ca 40 % minskning jämfört med kontrollen, men SRF ökade mängden italienskt rajgräs mer än TRF. TRF + SRF hade större effekt än en enda fragmentering och reducerade kvickrotsrhizomvikten med 55 % jämfört med kontrollen, medan skottvikten av italienskt rajgräs tripplades. Upprepad putsning reducerade kvickrotsrhizomvikten med ca 75 % och när putsning kombinerades med rhizomfragmentering var det en tendens till ännu större minskning, ca 80 % i genomsnitt. Vår slutsats är att rhizomfragmentering med vertikala diskar kan användas både innan sådd och i den växande grödan för att förbättra kontrollen av kvickrot i en gräs-klövergröda. The work of this paper is related to Task 1 in work package 2 of the FertilCrop Project - the control of weeds in reduced tillage systems. The conference was directed towards researchers and stakeholders in forage crop production in the Scandinavian countries (In Swedish). There were about 300 participants, researchers, advisors, industry, officials and farmers

Control of Elymus repens by rhizome fragmentation and repeated mowing in a newly established white clover sward

Control of perennial weeds, such as Elymus repens, generally requires herbicides or intensive tillage. Alternative methods, such as mowing and competition from subsidiary crops, provide less efficient control. Fragmenting the rhizomes, with minimal soil disturbance and damage to the main crop, could potentially increase the efficacy and consistency of such control methods. This study's aim was to investigate whether fragmenting the rhizomes and mowing enhance the control of E. repens in a white clover sward. Six field experiments were conducted in 2012 and 2013 in Uppsala, Sweden, and Ås, Norway. The effect of cutting slits in the soil using a flat spade in a 10 × 10 cm or 20 × 20 cm grid and the effect of repeated mowing were investigated. Treatments were performed either during summer in a spring-sown white clover sward (three experiments) or during autumn, post-cereal harvest, in an under-sown white clover sward (three experiments). When performed in autumn, rhizome fragmentation and mowing reduced E. repens shoot biomass, but not rhizome biomass or shoot number. In contrast, when performed in early summer, rhizome fragmentation also reduced the E. repens rhizome biomass by up to 60%, and repeated mowing reduced it by up to 95%. The combination of the two factors appeared to be additive. Seasonal differences in treatment effects may be due to rhizomes having fewer stored resources in spring than in early autumn. We conclude that rhizome fragmentation in a growing white clover sward could reduce the amount of E. repens rhizomes and that repeated mowing is an effective control method, but that great seasonal variation exists.publishedVersio

A survey on the uses of glyphosate in European countries

rapport européenInternational audienceIn 2019, the ENDURE network3 launched a survey on the agricultural use of glyphosate in Europeancountries. This report presents the results obtained through the survey and proposes a framework forunderstanding and monitoring glyphosate uses.The share of herbicides among all pesticide sales varies from one country to another. It is particularlyhigh in Sweden (where herbicides represented 85% of the total volume of pesticides sold in 2017),Norway (83%), Denmark (82%), Estonia (76%), Ireland (73%), Latvia (73%), Lithuania (63%), UnitedKingdom (62%) and Poland (61%) and is particularly low in Malta (2%), Cyprus (13%) and Italy (17%).When reported by hectare of agricultural area, the countries with the highest average use of herbicidesare Belgium, Netherlands, Cyprus, France, Germany, Denmark and Poland. The average use ofherbicides in the agricultural sector at the EU 28+3 level can be estimated at 0.62 kg of a.i. per hectare.The total volume of herbicides sold in all EU 28+3 countries remained rather stable from 2011 to 2017,while at the national level, herbicide sales numbers showed a high degree of fluctuation.The ENDURE survey made it possible to collect data on glyphosate sales in 25 countries. In addition,an estimation was calculated for the other seven countries for which no data could be obtained. Thetotal sales of glyphosate are estimated at 46,527 tonnes of a.i. in 2017 across the EU 28+3 (47,452tonnes of a.i. across the EU 28+4). Overall, sales of glyphosate represent 33% of total herbicide salesin the EU 28+3. Therefore, glyphosate is one of the most widely used herbicides in European agriculture.Similar to overall herbicide sales, glyphosate sales (in volume of active ingredients) appear to be thehighest in France (20% of the EU 28+4 total glyphosate sales volume in 2017), Poland (14%), Germany(10%), Italy (8%) and Spain (8%). Glyphosate represents 15% to 78% of total herbicide active ingredientsales in the countries surveyed. According to the survey, glyphosate is mainly used in the agriculturalsector. Across the 13 countries for which the share of glyphosate sales to the agricultural sector wasavailable, the agricultural sector consumes on average 90% of total national glyphosate sales (byvolume). When reported by hectare of agricultural area, the average use of glyphosate at the EU 28+3level is 0.20 kg a.i. per hectare. The five countries with the highest use of glyphosate in 2017 wereDenmark, Poland, Netherlands, Portugal and France (≥0.32 kg of a.i. per ha). The five countries withthe lowest use of glyphosate were Turkey, Lithuania, Latvia, UK and Switzerland (≤0.12 kg of a.i. perha)4.This report offers a framework for understanding and monitoring glyphosate uses in the agriculturalsector, based on the identification of the cropping systems in which glyphosate is used, the agronomicpurposes for which it is used and the nature of this use (from occasional to systematic). Glyphosate iswidely used in annual cropping systems, perennial crops and grasslands. In annual cropping systems,it is mostly used prior to sowing, shortly after sowing of the crop (at the pre-emergence stage) or at thepost-harvest stage for controlling weeds and volunteers. Annual cropping systems in which glyphosateis used include a large variety of crops (such as maize, oilseed rape, cereals, legume crops, sugar andfodder beet etc.). It is also used for the destruction of cover crops, and for ensuring the desiccation ofcertain annual crops at the pre-harvest stage. In perennial crops (such as vineyards, fruit orchards,olives groves etc.), glyphosate is used for controlling weeds within or between crop rows. Finally,glyphosate is used for the destruction of temporary grassland, for local control of perennial weeds inpermanent grassland and for grassland renewal. Overall, the survey shows that the herbicide is usedfor at least eight agronomic purposes.Statistical data regarding glyphosate use in annual cropping systems is limited. In addition, the allocationof glyphosate treatments that are applied in the intercropping period may vary across countries. Fourdifferent allocation rules were identified through the survey: allocation from harvest to harvest, allocationfrom field preparation to post-harvest treatments, allocation to the intercrop period and allocation to thecropping system. In some countries, several allocation rules may apply depending on the statisticaldataset. As a consequence, comparisons of glyphosate uses in annual cropping systems betweencountries or crops must be considered as a preliminary indication.Within the scope for which data could be obtained through the survey, 32% of the wheat acreage, 25%of the maize acreage and 52% of the oilseed rape acreage were treated with glyphosate in any singleyear. The treated acreage varies greatly from one country to another: the use of glyphosate in maizefields was almost inexistent in some countries, while it reached up to 40% of the crop area in othercountries. In oilseed rape fields, the share of the crop area treated with glyphosate varied from less than10% to more than 70%. Similarly, in winter wheat fields, the share of the crop area on which glyphosateis used varied from less than 10% to 90%. Those percentages include: treatments for controlling weedsapplied before cultivation (at the pre-sowing or pre-emergence stage) that may occur for each newsowing in the crop rotation; treatments for controlling weeds that are applied only once in the croprotation (at a post-harvest stage or during an intercropping period); and desiccation/harvest aid for someof the crops (in countries in which this is allowed). As the percentages are for any single year, the areatreated with glyphosate in any region over a full crop rotation period may be greater. Additional researchis needed for assessing the total uses of glyphosate throughout the crop rotations in EU countries.In perennial systems, within the scope for which data was available in the EU 28+4, 39% of the fruitorchard acreage, 32% of the vineyard acreage and 45% of the olive grove acreage were treated withglyphosate. Across countries, the use of glyphosate ranged from 13% to 95% of the national vineyardacreage, from 20% to 92% of the fruit orchard acreage and from 13% to 80% of the olive grove acreage.Finally, 19% of the temporary grassland acreage was treated with glyphosate annually.A diversity of non-chemical alternatives to glyphosate treatments can be identified. Their effectiveness,cost and adoption implications for crops and the environment can vary widely, or may not be quantified.They include both preventive measures and curative control measures, such as mechanical andbiological control. In annual cropping systems, these practices include: use of cover crops and of aroller-crimper for their destruction, mulching, crop rotation diversification, delaying crop sowing dates,higher seed rates, increasing crop competitiveness, inter-row cultivation, tillage for controlling weeds atthe post-harvest and pre-sowing stages, use of early-ripening varieties and weed seed removal duringharvest. In perennial crops, the following alternatives were identified: greening, grazing, mowing,mulching, cover crops, tillage, mechanical weeding and the use of bioherbicides for weed control.Different approaches to using glyphosate were identified through the survey. Occasional uses arerelated to exceptional contexts, such as meteorological conditions or specific farm constraints.Recurrent uses are widespread practices that are already embedded in farming systems. Otheragronomic solutions may exist but are not mobilised; instead farmers plan to, and recurrently do, useglyphosate. Two types of recurrent uses can be distinguished: uses related to structural conditions andsystematic uses that are not related to structural conditions. First, uses related to structural conditionsappear when equipment or infrastructure are not compatible with alternative practices. Examples ofsuch structural conditions include irrigation systems that are located above ground in fruit orchards andnarrow rows in orchards or vineyards which prevent weed management using mechanical methods. Forreplacing glyphosate with non-chemical alternatives, a change in these structural aspects is required,which may involve significant investments. Second, systematic uses not related to structural conditionsresult from the evolution of farming systems generally characterised by reduced tillage systems, largescalefarms and the availability of highly efficient, low-priced herbicides such as glyphosate. Examplesof systematic uses include the use of glyphosate for crop desiccation, for the destruction of cover cropsand temporary grasslands, and for weed management in annual and perennial crop systems. In thecase of systematic uses, multiple inter-related factors may hinder the shift to non-chemical alternatives.These include: limited, and in some cases no, availability of and access to alternative inputs and adaptedmachinery; constraints and opportunities due to regulations and subsidies; lack of advice, knowledgeand references regarding alternative practices; uncertainties, risks and variability in agronomicperformance and profitability of alternative practices; constraints in farm resources; commercial context;challenges in terms of labour organisation; and cultural and cognitive aspects.Further research is needed to assess the conditions, including the economic and technical aspects aswell as systemic contexts, that are required for enhancing the adoption of non-chemical alternatives toglyphosate