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A Danish decision support system for integrated management of weeds

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... Crop Protection Online-Weeds (CPO-Weeds) is a knowledge-driven decision support system (DSS) for chemical weed control and offers support for herbicide and dose selection in a variety of crops [9,14]. CPO-Weeds suggests management options based on a large database comprising existing knowledge on herbicides and herbicide efficacies. ...
... Herbicide recommendations in CPO-Weeds are calculated through a three step process following the user's input on weed composition in the field [9,14]. The first step is to determine whether the weed infestation requires control. ...
... This led to average required control levels of around 70 % including the scenarios that were below the economic threshold and did not call for any herbicide application. The validations of this version showed that CPO-Weeds maintained its robustness, and larger herbicide reductions were achieved [14,18,19]. Some additions/changes to CPO-Weeds have improved the DSS, while others have been found merely to increase complexity for the users without adding any real benefits. ...
Chapter
Crop Protection Online—Weeds (CPO-Weeds) is a decision support system for weed control developed in Denmark and later adjusted to conditions in several other countries. In Denmark, the DSS includes all major crops and available herbicides. The background for developing CPO-Weeds was a political motivation for reducing pesticide use and the concept of factor-adjusted doses. It was never the intention to build a sophisticated scientific model, but rather to design a simple user-friendly system. It is a knowledge-driven DSS, which offers herbicide dose suggestions based on a large database of the existing knowledge of herbicides and herbicide efficacies. The required weed control level in CPO-Weeds is based on expert evaluations, a herbicides dose-response model and an additive dose model to calculate possible mixtures of herbicides targeted a specific weed population. The herbicide dose model is a two parameter dose-response model, which is modified to include the effects of temperature, weed growth stage and influence of drought. The development has been driven by an ambition of offering a robust system with relatively low amounts of input variables and limited need for experimental parameter generation. CPO-Weeds offers overview and guidance for field specific spraying solutions, and the system has proved able to recommend herbicide doses with considerable reductions compared to label rates. Furthermore, CPO-Weeds offers a variety of tools that summarises knowledge of herbicides for a wide range of questions asked by practical weed managers, e.g. efficacy profiles of each herbicide, efficacy of users own herbicide mixtures, weed identification key and guidance for spraying strategy. The experiences have shown that even though CPO-Weeds are considered robust and trustworthy by both farmers and advisors there is a relatively low number of farmers subscribing to the system. A survey revealed that the DSS falls in between the strategies of many farmers; either the farmers relies completely on own experiences or advisory services or they considers the full crop rotation in their weed management. The latter is not supported by CPO-Weeds, which focus on a single season. The long term consequences of herbicide recommendations is only included in the need to limit input to soil seed bank. Another limiting factor for an increased practical use of CPO-Weeds is the need for field monitoring of weed populations, which can be a time consuming task and requires extensive weed recognising abilities of the farmer at the very early growth stages of weeds. The intention of CPO-Weeds was to provide recommendations for the full spraying season of a field, but experiences have shown that the system has several uses. Many farmers spray with a standard solution in the autumn in winter crops and then use the DSS for spring sprayings. The relatively simple input requirements also make the DSS suitable for teaching purposes and for farmers starting to grow new crops in their rotation as a learning tool.
... A slightly different approach is employed by Crop Protection Online (CPO), which is a DSS for optimal herbicide use developed in Denmark (Kudsk, 2008;Rydahl, 2003Rydahl, , 2004Sønderskov et al., 2014). CPO can aid the farmer in decision making concerning the need for weed control and the optimal herbicide combination and dose. ...
... The herbicide reductions obtained with DSSHerbicide in Germany and Poland were consistent with the previous experiences from Denmark with the existing CPO in practical weed management trials (Rydahl, 2004). In Danish winter cereals, the TFI has been observed to be approximately 30% lower compared to a treatment recommended with an earlier version of CPO, which had higher target efficacies (Rydahl, 2004). ...
... The herbicide reductions obtained with DSSHerbicide in Germany and Poland were consistent with the previous experiences from Denmark with the existing CPO in practical weed management trials (Rydahl, 2004). In Danish winter cereals, the TFI has been observed to be approximately 30% lower compared to a treatment recommended with an earlier version of CPO, which had higher target efficacies (Rydahl, 2004). In the present study, there were no differences between the Danish standard The boxes represent treatments with decreasing colour intensity in the order; Standard recommendation 1 (darkest grey), Standard recommendation 2, DSSHerbicide-high, DSSHerbicide-standard, DSSHerbicide-low (white). ...
... These methods require use of field reports on actual weed infestations, i.e. combinations of weed species and classes of density growth stages. Upon entering, the DSS will: 1) quantify needs for control on a weed species level, 2) identify single herbicides, which can meet identified needs for control, 3) select and optimize (for cost or various index) suitable 2-4 way herbicide tank-mixtures and 4) present options for treatment (Rydahl, 2004). ...
... Due to generic qualities in agro-biological modelling and IT basis, IPMW is currently being customized for professional use also in countries abroad, mainly Norway, Germany and Spain, and start-up activities are in progress in additional EU countries. In all countries involved so far, DSS has demonstrated sufficiently robust IWM, and potentials for reducing the use of herbicides in the range of 20-40% as compared to local 'best practice' programs Reduction (Rydahl, 2004;Tørresen et al., 2004;Sønderskov et al., 2014;Sønderskov et al., 2015;Montull, 2016). However, in all countries involved, a common recognized major bottleneck for a wider exploitation of reduction potentials has been identified in terms of reluctance among farmers to conduct manual field inspections (Jørgensen et al., 2007). ...
... When weeds are overlapping with other plants, systematic underestimations of weed density may be expected. However, according to design of DSS (CPO or IPMW) (Rydahl, 2004;Rydahl, 2016), only some such imperfections are important, while others may be automatically corrected for or just ignored, without jeopardizing requirements for agronomic robustness, according to the DSS design. Important is, however, not to completely overlook species, which cause serious economic losses, and/or which require special control measures. ...
Article
In order to exploit potentials of 20–40% reduction of herbicide use, as documented by use of Decision Support Systems (DSS), where requirements for manual field inspection constitute a major obstacle, large numbers of digital pictures of weed infestations have been collected and analysed manually by crop advisors. Results were transferred to: 1) DSS, which determined needs for control and connected, optimized options for control returned options for control and 2) convolutional, neural networks, which in this way were trained to enable automatic analysis of future pictures, which support both field- and site-specific integrated weed management.
... CPO-Weed works as a three step model (RYDAHL, 2004). Firstly, the need for weed control is assessed based on evaluation of the economic impact of each of the weed species recorded in the field. ...
... Field test of CPO-Weed have revealed a significant potential for reducing herbicide use compared to the current practice (JØRGENSEN and KUDSK, 2006). For more information on CPO-Weed see RYDAHL (2004) andSØNDERSKOV et al. (2013). ...
Article
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Applying herbicides at rates lower than the label recommendation has been the rule rather than the exception in Denmark since the late 1980’s. Justifications for reducing herbicide rates can be 1) that the dominant weed species in the field are very susceptible to the herbicide, i.e. even reduced rates will result in maximum effects, 2) that the conditions at and around the time of application, e.g. growth stage of weeds, crop vigour and climatic condition are optimum promoting the activity of the herbicide and thus allows for the use of reduced herbicides rates, or 3) that less than maximum effects are accepted because the weed flora is not considered to have a significant effect on crop yield. “Crop Protection Online-Weed” (CPO-Weed) is a web-based decision support system that was developed to support farmers in their choice of herbicide and herbicide rate. CPOWeed will, based on information on crop development and status and the composition of the weed flora, provide farmers with a list of herbicide solutions often recommending the use of reduced rates. The potential of CPO-Weed to reduced herbicide input has been proven in numerous validation trials. In recent years the use of reduced herbicide rates has been linked to the increasing number of cases of non-target resistance in outcrossing grass weed species like Alopecurus myosuroides and Lolium ssp. The underlying hypothesis is that the least susceptible individuals in the population will survive the use of reduced rates and that recombination will lead to a gradual increase in the resistance level in the weed population. This scenario is only valid if the use of reduced herbicide rates is prompted by acceptance of a lower effect but not if a high susceptibility of the weed species present in the field or optimum conditions are the reasons for reducing herbicide rates. This is an aspect that is often overlooked in the on-going discussion on herbicide rates and resistance. Large weed population increases the risk of selecting resistant weed biotypes because the likelihood that resistant plants are present in the population increases with population size. Preventing the build-up of large weed populations is a key objective in integrated pest management (IPM). If the use of herbicide is combined with non-chemical weed control methods the risk of resistance will be reduced further, i.e. in an IPM scenario the use of reduced herbicides rates will be less likely to promote herbicide resistance even if it is triggered by an acceptance of lower effects.
... To reduce the use of herbicides in agriculture, farmers must have knowledge of the condition of weeds in their field, in order to spray optimally, whilst minimizing the herbicide consumption. A compilation of the current top five factors for selecting herbicides and dosages lists "determination of weed species" and "determination of classes of weed growth stage" as Nos. 2 and 3 in importance [1]. Across major crops in Denmark, there is an unexploited potential to achieve a 20-40% reduction in herbicide use, whilst maintaining weed control, by targeting specific weeds, in situ [1]. ...
... A compilation of the current top five factors for selecting herbicides and dosages lists "determination of weed species" and "determination of classes of weed growth stage" as Nos. 2 and 3 in importance [1]. Across major crops in Denmark, there is an unexploited potential to achieve a 20-40% reduction in herbicide use, whilst maintaining weed control, by targeting specific weeds, in situ [1]. However, a sociological study has shown that Danish farmers are reluctant to conduct field scouting and that recognition of weeds (in various growth stages) is a major obstacle to targeted weed control [2]. ...
Article
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This study outlines a new method of automatically estimating weed species and growth stages (from cotyledon until eight leaves are visible) of in situ images covering 18 weed species or families. Images of weeds growing within a variety of crops were gathered across variable environmental conditions with regards to soil types, resolution and light settings. Then, 9649 of these images were used for training the computer, which automatically divided the weeds into nine growth classes. The performance of this proposed convolutional neural network approach was evaluated on a further set of 2516 images, which also varied in term of crop, soil type, image resolution and light conditions. The overall performance of this approach achieved a maximum accuracy of 78% for identifying Polygonum spp. and a minimum accuracy of 46% for blackgrass. In addition, it achieved an average 70% accuracy rate in estimating the number of leaves and 96% accuracy when accepting a deviation of two leaves. These results show that this new method of using deep convolutional neural networks has a relatively high ability to estimate early growth stages across a wide variety of weed species.
... Crop Protection Online (CPO) is a DSS developed and managed by Aarhus University, which was commercialised in 1991 (Rydahl, 2003(Rydahl, , 2004Kudsk, 2008a). CPOWeeds optimises herbicide combinations and dosages in relation to the actual crop and weed infestation either by lowest dose or lowest price. ...
... This was done by shifting the doseeresponse curve to the right. (Kudsk, 2008b) (Rydahl, 2004) (Rydahl, 2003) Some non-parameterized species were regarded equally susceptible to an herbicide as another species by local experts and similar doseeresponse curves were adopted in the system for those species. ...
Article
The Danish decision support system Crop Protection Online (CPO) optimises herbicide weed control. CPO recommends specific herbicide solutions to achieve a required level of control. The aim is to apply herbicides as little as possible but as much as necessary. CPOWeeds is a version of CPO adjusted to conditions in North-eastern Spain. The predicted efficacies and the yield obtained with CPOWeeds were validated in winter cereal field trials from 2010 to 2013. All CPOWeeds treatments were related to the efficacies obtained with standard herbicide treatments decided upon by local advisors. The predictions from CPOWeeds were compared to the actually achieved efficacies in the field trials for the nine weed species at different developmental stages and for 84.2% of the comparisons the obtained efficacies were equal to or higher than predicted. The average difference between predicted and observed efficacies was 2.35 percentage points. Yield was measured in three trials and the recommendations from CPOWeeds were maintaining yield. There were two situations where CPOWeeds were performing suboptimal. One is in the early weed growth stages, as the model is not yet prepared to account for water stress on root action herbicides applied at 10-11 BBCH. The second situation was in fields with a prior unidentified population of resistant Alopecurus myosuroides. For key species in winter cereals in Spain, such as Avena sterilis, Lolium rigidum and Papaver rhoeas, CPOWeeds achieved a satisfactory control level. It was concluded that the use of CPOWeeds allowed optimisation of the herbicide application with a very high robustness. The recommendations were satisfactorily for the conditions of the Northeast of Spain and have the potential to decrease the amount of applied herbicides by at least 30%. Therefore, it can be an important tool in Integrated Weed Management.
... Most DSS are devoted to typical annual weeds in wheat based rotations Doyle et al., 1986;Berti et al., 2003;Pannell et al., 2004;Parsons et al., 2009), but other crops, such as soybean and sugar beet, have also been modeled (Berti and Zanin, 1997;De Buck et al., 1999;Rydahl, 2004). Most systems were also designed in European countries Fernández-Quintanilla, 1991, 2004;Berti and Zanin, 1997;Falconer and Hodge, 2001;Berti et al., 2003;Colbach et al., 2007;Parsons et al., 2009;Torra et al., 2010). ...
... In this way, different possible scenarios can be tested and ranked according to their economic output. However, due to the combinatorial amount of feasible control options (chemical and non-chemical) on a long term time-horizon of several seasons, some DSS also implement numerical optimization algorithms to automate the search (Sells, 1995;De Buck et al., 1999;Falconer and Hodge, 2001;Mullen et al., 2003;Rydahl, 2004;Parsons et al., 2009). ...
... There has been a move towards conservation agriculture to improve sustainability without compromising land, and at the same time is an effective way of reducing soil erosion and maintaining soil water content [1,2,3,4]. However, conservation agriculture can lead to specific problems with weed control because without tillage farmers have no option but to rely on herbicides [5,6,7]. ...
... These results agree with those obtained by other author in similar conditions [7,27,54,25]. The continuous cereal systems, in northern Spain, are common and weed control in these soil non-inversion conservation techniques (minimum tillage and no-tillage systems), is difficult to achieve because of these systems are dependent on herbicides [5]. Also, tillage system variant applied is crucial to weed species control [55]. ...
... This is valuable to support decisions on supplementary control measures (Kempenaar, 2008). Originality in Da_CPOWeeds are the integration of different criteria to quantify the need for weed control, the use o dose-response functions to quantify herbicide efficacy in different conditions, the optimization of compositions of 2- 4 herbicides and the strategy to manage multiple herbicide treatments (Rydahl, 2004). ...
... However, most DSS's have only sparsely been validated for long-term aspects. For Da_CPOWeeds, however, level of residual weeds have been registered by routine in >1,500 field tests of different DSS-prototypes (Rydahl, 2004). For the presently distributed version, the Input of herbicides were reduced >40% in cereals. ...
... In the case of weed management, the designers do not systematically specify in their papers who the targeted users of the decision support systems are. Only a few studies actually involved users in the designing process (Parsons et al. 2009), transferred decision support systems to users (Munier-Jolain et al. 2004) or analysed the use of the decision support system (Rydahl and Boejer 2007). ...
Article
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The present major agricultural issues are to feed the world and reduce negative environmental impacts. To this end, organic farming appears as a promising solution. However organic farming has several drawbacks such as difficult weed management. Indeed weeds can reduce crop yields. Therefore there is a need for improved decision support tools for weed management in organic farming. An existing weed competition model actually predicts the effect of early multispecies weed density, both on organic wheat yield loss and on the weed density at flowering stage. However main existing models do not take into account the activity of end-users, e.g. farmers, during model design. Therefore we analysed weed information acquisition by farmers using the dynamic environment theory to design a decision support system that takes into account end-users. We interviewed eight French organic farmers. We analysed interview data using a coding scheme inspired by dynamic environment theory. Our results show that weed quantity was the information most frequently collected by organic farmers both for short- and long-term crop management. This information was compatible with early weed density, the main input of the previously developed models. Findings also show that procedures for gathering information and processing depended on farmer profiles. We also show that a conceptual model based on dynamic situations and a coding structure were appropriate for taking into account the information elaborated by end-users. Finally we propose further design of a decision support system for tactical organic weed management using a participatory approach.
... Subsequently, in 2004Subsequently, in , 2005Subsequently, in and 2006, A. spica-venti was controlled by post-emergence herbicide application, with treatments including three target levels: no control (i.e. no herbicide application); 70% control; and 90% control, based on the Danish Decision Support System for chemical weed management (Rydahl, 2004) (Table 3). Herbicides with no expected effect on A. spica-venti were likewise used to control broad-leaved weeds, with a target control level of 90%. ...
Article
Apera spica-venti is a winter annual grass and, increasingly, a severe weed problem in autumn-sown crops. Non-inversion tillage has become more common in Denmark in recent years, but may accentuate problems with A. spica-venti. These problems may be avoided, if selected preventive and cultural weed management practices are adopted. To this end, we conducted a 4-year field study investigating the effects of crop rotation, tillage method, location and limited herbicide input on A. spica-venti population dynamics and crop yield. Additionally, detailed studies were performed on the fate of A. spica-venti seeds when incorporated to different soil depths. The location with a lighter soil texture, cooler climate and higher rainfall favoured A. spica-venti growth and consequently crop yield loss, especially in the crop sequence comprised only of autumn-sown crops and with non-inversion tine tillage. Incorporating A. spica-venti seeds in the soil improved their survival, explaining the higher A. spica-venti proliferation seen with tine tillage as opposed to direct drilling. The rotations including an even mixture of spring- and autumn-sown crops did not lead to noteworthy changes in the A. spica-venti population, irrespective of tillage method. Thus, in many regions, management of A. spica-venti will require rotations that balance autumn- and spring-sown crops.
... De relevante organismer er i denne sammenhaeng: Bier (indikator 7), den mest følsomme af de to organismer der indgår i godkendelsesmaterialet i kategorien "andre leddyr" (indikator 8), samt planter (indikator 9). Fordi der ikke findes effektdata for vilde planter, er belastningstallet for denne delindikator baseret på de EC 50 -vaerdier, der findes for ukrudtplanter i Plantevaern Online (Rydahl, 2004). I Plantevaern Online er der for glyphosat kun vaerdier for en enkelt ukrudtsplante. ...
... Not only new data but also historical data have been valuable inputs developing threshold and forecasting models for diseases and pests. More details on the development of CPO can be found elsewhere (Rydahl 2003(Rydahl , 2004Rydahl et al. 2003;Hagelskjaer and Jørgensen 2003;Jørgensen et al. 2008). ...
In 1986 Denmark adopted, as the first country in Europe, a pesticide action plan calling for 50% reduction in pesticide use. The first pesticide action plan was later followed by three other pesticide action plans and recently the Danish government announced the fifth pesticide action plan covering the period 2013 to 2015. As a result of the long-standing public pressure to reduce pesticide use numerous research and advisory activities have been initiated to provide farmers with the knowledge and tools required to meet the goals. This chapter: (1) provides an overview of the content of the pesticide action plans; (2) presents the research and advisory activities supported by the pesticide action plans; (3) gives examples of the IPM tools that are available to Danish farmers; and (4) describes the most recent political initiatives including the new Pesticide Load Indicator that will replace the Treatment Frequency Index. © 2014 Springer Science+Business Media Dordrecht. All rights reserved.
... The 70% target control level against A. spica-venti was abandoned from autumn 2010, and hereafter all doses were raised to target 90% control of grass weeds due to increasing grass weed problems in the non-inverted tillage treatments. Herbicide choices and doses against broadleaved weeds and doses of the graminicides were based on the recommendations of Crop Protection Online, a Danish decision support system for chemical weed management (Rydahl, 2004). ...
... Therefore, dose flexibility is not as great as in some other weed DSSs 541 (e.g. Rydahl, 2004). An advantage of our method is that herbicide parameter updates are 542 straightforward, as they can be extracted from labels. ...
Article
The ‘within-season’ module of the Weed Manager decision support system (DSS) predicts the effect of twelve UK arable weeds on winter wheat yields and profitability. The model and decision algorithm that underpin the DSS are described and their performance discussed. The model comprises: (i) seedling germination and emergence, (ii) early growth, (iii) phenological development, (iv) herbicide and cultivation effects and (v) crop yield loss. Crop and weed emergence are predicted from the timing and method of cultivation, species biology, and the weather. Wheat and weeds compete for resources, and yield losses are predicted from their relative leaf area at canopy closure. Herbicides and cultural control methods reduce weed green area index, improving crop yield. A decision algorithm identifies economically successful weed management strategies based on model output. The output of the Weed Manager model and decision algorithm was extensively validated by experts, who confirmed the predicted responses to herbicide application were sufficiently accurate for practical use. Limited independent data were also used in the validation. The development of the module required integrating novel and existing approaches for simulating weed seedling establishment, plant development and decision algorithm design. Combining these within Weed Manager created a framework suitable for commercial use.
... An effective way to reduce the side effects of the herbicides, according to the Integrated Weed Management 2 weed species" combinations (Dogan & Boz, 2005;Kudsk 2008;Pannacci et al., 2010). Furthermore, the knowledge of MDRE is one of the main factors in the implementation of the Decision Support Systems for Integrated Weed Management (Rydahl, 2004;Sønderskov et al., 2015), with the aim to decrease the dependence on herbicides that has become a distinct objective within the EU with the directive 2009/128/EC. The determination of MDRE requires dose-response studies for each "herbicide-weed species" under various environmental conditions (Kudsk & Kristensen, 1992;Pannacci & Covarelli, 2009). ...
Article
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Four field experiments were carried out from 2011 to 2014 in order to evaluate the effects of foramsulfuron, applied at the recommended (60.8 g a.i./ha) and reduced doses (1/3 and 2/3), on the efficacy against several of the most important weeds in maize. For each “year-weed” combination, dose-response curves were applied to estimate the dose of foramsulfuron required to obtain 90% and 95% weed control (ED90 and ED95). Foramsulfuron phytotoxicity on maize and crop yield were assessed. Foramsulfuron at 1/3 of the recommended dose (20.3 g a.i./ha) provided 95% efficacy against redroot pigweed (Amaranthus retroflexus L.), green foxtail (Setaria viridis (L.) Beauv.), wild mustard (Sinapis arvensis L.) and black nightshade (Solanum nigrum L.). Velvetleaf (Abutilon theophrasti Medik.), common lambsquarters (Chenopodium album L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv.) were satisfactorily controlled (95% weed efficacy) with ED95 ranged from 20 to 50 g/ha of foramsulfuron (about from 1/3 to 5/6 of the recommended dose) depending on growth stage. The recommended dose was effective against pale smartweed (Polygonum lapathifolium L.) at 2-4 true leaves (12-14 BBCH scale), but this dose did not kill plants larger than 2-4 true leaves. The ranking among weed species based on their susceptibility to foramsulfuron was: redroot pigweed = green foxtail = wild mustard = black nightshade > velvetleaf = common lambsquarters = barnyardgrass > pale smartweed. Dose of foramsulfuron can be reduced below recommended dose depending on weed species and growth stage. Foramsulfuron showed a good crop selectivity and had no negative effect on maize yield.
... The target fertilizer applications (NH 4 -N in slurry plus N in mineral fertilizer) were winter wheat (Triticum aestivum L.)165, winter rape (Brassica napus L.) 171, winter barley (Hordeum vulgare L.) 139, spring barley (Hordeum vulgare L.) 117, and oat (Avena fatua L.) 92 kg N ha -1 . Weeds and pests were controlled using pesticides based on the recommendations of Crop Protection Online, a Danish decision support system (Rydahl, 2004). More details on crop management have been reported by Hansen et al. (2010Hansen et al. ( , 2015. ...
Article
Conservation agriculture (CA) has been suggested as a means of making intensification of agriculture sustainable. The purpose of this study was to understand and quantify long-term individual and combined effects of key conservation practices on soil physical properties and topsoil carbon content. Field experiments were conducted in 11- to 12-year-old experiments on two Danish sandy loams at Foulum and Flakkebjerg. Three crop rotations/residue management treatments were compared and tillage was included as a split-plot factor. The tillage systems were moldboard plowing to a depth of 20 cm (MP), direct drilling (D) and harrowing to a depth of 8-10 cm (H). Soil sampling and in-field measurements were carried out in autumn 2013 and spring 2014. In the field, soil structure was visually evaluated and penetration resistance measured. Soil carbon, wet stability (clay dispersion and wet aggregate stability), and soil strength were determined in the laboratory. The MP soil had a uniform soil organic carbon (SOC) content in the 0- to 20-cm topsoil, whereas H and D resulted in SOC accumulation near the soil surface. Plowing resulted in the best visually-assessed topsoil structure and had the lowest penetration resistance. However, H and D in combination with residue retention gave the best structural stability. Residue retention alleviated negative effects of reduced tillage on penetration resistance and improved wet stability in the MP treatment at the Foulum site. Clay and SOC correlated well with soil physical parameters, confirming their important role in soil structure formation and stabilization. Our study showed benefits of combining key CA elements, although longer-term studies are most likely needed to reveal the full potential. Keywords: rotation, conservation tillage, residue retention, soil quality, soil structure
... These data can be used to derive risk factors for weeds and to determine how effective weed control measures are. Several model-based decisionsupport systems for weed management in arable crops are already available, taking advantage of the tank of Big Data (Berti et al., 2003;Rydahl, 2004;Parsons et al., 2009). ...
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p>Farmers have access to many data-intensive technologies to help them monitor and control weeds and pests. Data collection, data modelling and analysis, and data sharing have become core challenges in weed control and crop protection. We review the challenges and opportunities of Big Data in agriculture: the nature of data collected, Big Data analytics and tools to present the analyses that allow improved crop management decisions for weed control and crop protection. Big Data storage and querying incurs significant challenges, due to the need to distribute data across several machines, as well as due to constantly growing and evolving data from different sources. Semantic technologies are helpful when data from several sources are combined, which involves the challenge of detecting interactions of potential agronomic importance and establishing relationships between data items in terms of meanings and units. Data ownership is analysed using the ethical matrix method to identify the concerns of farmers, agribusiness owners, consumers and the environment. Big Data analytics models are outlined, together with numerical algorithms for training them. Advances and tools to present processed Big Data in the form of actionable information to farmers are reviewed, and a success story from the Netherlands is highlighted. Finally, it is argued that the potential utility of Big Data for weed control is large, especially for invasive, parasitic and herbicide-resistant weeds. This potential can only be realised when agricultural scientists collaborate with data scientists and when organisational, ethical and legal arrangements of data sharing are established.</p
... However, the area in which the cumulative emergence was assessed (rings) was not sprayed. Herbicide choices and doses against broad-leaved weeds and doses of the graminicides were based on recommendations provided by Crop Protection Online (Rydahl, 2004). ...
Article
Annual grass weeds such as Apera spica-venti and Vulpia myuros are promoted in non-inversion tillage systems and winter cereal-based crop rotations. Unsatisfactory weed control in these conditions is often associated with a poor understanding of the emergence pattern of these weed species. The aim of this study was to investigate, understand and model the cumulative emergence patterns of A. spica-venti, V. myuros and Poa annua in winter cereals grown in three primary tillage regimes: (i) mouldboard ploughing, (ii) pre-sowing tine cultivation to 8–10 cm soil depth and (iii) direct drilling. Direct drilling delayed the cumulative emergence of A. spica-venti and V. myuros (counted together) in contrast with ploughing, while the emergence pattern of P. annua was unaffected by the type of tillage system. The total density of emerged weed seedlings varied between the tillage systems and years with a higher total emergence seen under direct drilling, followed by pre-sowing tine cultivation and ploughing. The emergence patterns of all species were differently influenced by the tillage systems, suggesting that under direct drilling, in which these species occur simultaneously, management interventions should first and foremost consider that A. spica-venti and V. myuros emerge over a longer period to avoid control failures.
... PA can also be used to make actions temporally precise. In this mode, a decision is made when (if at all) to perform an operation, for example to control weeds [16,17], to control late blight [18], or to control plant parasitic nematodes [9]. ...
Article
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For farmers, the application of Precision Agriculture (PA) technology is expected to lead to an increase in profitability. For society, PA is expected to lead to increased sustainability.The objective of this paper is to determine for a number of common PA practices how much they increase profitability and sustainability. For potato production in The Netherlands, we considered variable rate application (VRA) of soil herbicide, fungicide for late blight control, sidedress N, and haulm killing herbicide. For olive production in Greece, we considered spatially variable application of P and K fertilizer and lime. For each of the above scenarios, we quantified the value of outputs, the cost of inputs, and the environmental costs. This allowed us to calculate profit as well as social profit, where the latter is defined as revenues minus conventional costs minus the external costs of production. Social profit can be considered an overall measure of sustainability. Our calculations show that PA in potatoes increases profit by 21% (420 € ha⁻¹) and social profit by 26%. In olives, VRA application of P, K, and lime leads to a strong reduction in nutrient use and although this leads to an increase in sustainability, it has only a small effect on profit and on social profit. In conclusion, PA increases sustainability in olives and both profitability and sustainability in potatoes.
... Weed control in these non-inversion tillage systems is very difficult to achieve with only herbicides as a resource (Rydahl 2004), and it will depend to a high extent on the tillage system variant put into practice (Dorado and López-Fando 2006). Also, the specific weeds in the area and the crop selection on the land are considered worthy of being analysed, because weeds germination can take advantage over crops due to, among other factors, the weather variability, which complicates the choice of agricultural practices and causes serious economic losses, and (or) which requires special control measures. ...
Article
In barley cropping systems of northern Spain, agronomic practices and weather conditions are key components of weed control efficacy. We compared the short-term effects of conventional tillage (CT) with minimum tillage (MT) and zero-tillage (ZT), in barley monoculture and barley rotation systems. Weed density and weed species number were measured at tillering and flowering barley stages. We found that tillage system can influence weed density and weed species establishment due to, in part, the available light for weed seeds. The results obtained led us to believe that MT system facilitate the prevalence of the grass weed Bromus diandrus Roth (50.37%) and the annuals dicots Galium aparine (L.) and Lithospermun arvense (L.) abundant were high in MT system too, 43.71% and 43.97% respectively. The germination of these species showed high dependence of light availability. We saw that barley-monoculture plots had a great infestation of Bromus (71.29%) and barley-rotated plots presented more infestation of Galium and Lithospermun (74.36% and 84.4%). After herbicide application, weed infestation in conservation systems was reduced in barley-rotated plots compared to barley-monoculture. If conservation systems avoided the presence of dominant weeds, the weight of each weed species was balanced within competitive relationships of the cropping systems. Our results confirmed that MT and ZT systems favour different weed species emergences in barley-rotated plots. The combination of MT and barley rotated cropping system resulted in terms of greater weed diversity and lower total weed density.
... Subsequently, in 2004Subsequently, in , 2005Subsequently, in and 2006, A. spica-venti was controlled by post-emergence herbicide application, with treatments including three target levels: no control (i.e. no herbicide application, referred to as 'AU'); 70% control (A 70%); and 90% control (A 90%), based on the Danish Decision Support System for chemical weed management (Rydahl, 2004). Herbicides with no expected effect on A. spica-venti were likewise used to control broadleaved weeds, with a target control level of 90%. ...
Article
On the basis of one 12-year lasting experiment in Germany and one 4-year lasting experiment in Denmark, different crop rotations, soil tillage intensities, and strategies of pesticide use were investigated with regard to yield, humus replacement, nitrogen (N) balance, energy use efficiency as well as acute and chronic risk potentials for aquatic and terrestrial organisms due to pesticide application. The investigation of the Danish experiment concerned two crop rotations (continuous winter wheat cropping, ‘FR 1’; winter oilseed rape–winter wheat–winter wheat–winter barley, ‘FR 2’), three intensities of soil tillage (ploughing, ‘P’; tine tillage ‘H8–10’; direct drilling, ‘D’) and three target control levels against Apera spica-venti (untreated, ‘AU’; 70% control, ‘A 70%’; and 90% control, ‘A 90%’), whilst the German experiment comprised one arable crop rotation (winter oilseed rape–winter wheat–winter rye–peas–winter wheat–winter barley, ‘DR 1’) and one fodder crop rotation (winter oilseed rape–winter barley–alfalfa/clover/grass-mixture–winter rye–silage maize–winter wheat, ‘DR 2’) each crop with situation-related pesticide use (100% HF) or application rates reduced by 50% (50% HF). At both sites, rotations and treatments were located on the same plots in each year. The study comprises the harvest years 2003–2006.
Article
Persistence of seeds of the four winter annual grass species, Alopecurus myosuroides, Bromus sterilis, Bromus hordeaceus and Vulpia myuros, were studied under field conditions. The studies also included the two dicotyledon species, Tripleurospermum inodorum and Galium aparine. Seed samples were stored in the field at different depths in the plough layer for a year. Following germination, seedling emergence was taken as an indicator of field persistence. In a supplementary investigation, seed samples were placed on the soil surface or buried at 2 cm for a month and then tested for viability. Persistence of the two Bromus species was very short, irrespective of depth and duration of burial. Persistence of the other species was positively correlated with incorporation of seeds to a few centimetres depth. Increasing the depth of incorporation below 2 cm had a variable influence on persistence. Persistence of seeds placed directly on the soil surface was short, whether they were left there for a year or a month. Whether seeds at the soil surface were left uncovered or covered with chopped straw had limited influence on seed persistence. However, straw cover significantly increased persistence of A. myosuroides seeds and there was the same tendency with T. inodorum.
Article
Full-text available
A survey has been conducted of decisions support systems (DSS's) for weed control in Europe. 9 DSS's representing 7 countries were studied. These were all targeted at farmers, but they differed in decisions supported, in number of crops covered and in demonstrated impact. At a workshop in Denmark in March 2008, a set of 'best parts' / 'building blocks' from these DSS's suitable for unification of a European level was identified. These could form the basis for building and validating DSS's on a European level that meets requirements for robustness in production lines and which hold some potential for reducing dependency and / or use of herbicides. When some robust and potent DSS concepts have been identified, the production and exchange of data that support integrated decision algorithms and calculation models of such DSS should be co-ordinated on a European level.
Chapter
For precision weed management decision rules are needed that take into account spatial and temporal variability of weed populations and weed-crop interactions. The following chapter describes different decision rules for online and offline site-specific weed management. Those decision rules use crop-weed competition models, dose-response functions, weed population models and cost functions to calculate the best intensity of weed control for each field section. It is shown that herbicide input and weed control costs can be significantly reduced when farmers use those models in combination with modern sensor and application technologies.
Article
Annual grasses constitute a major weed problem in winter annual crops in Northern Europe and especially in cropping systems where ploughing is omitted. At the optimum growth stage for control with POST herbicides, grasses have a predominantly vertical leaf orientation. This represents a very difficult spray target using the standard technique where nozzles are mounted more or less vertically downward. In this study, efficacy of the foliar-acting herbicide, haloxyfop, on perennial ryegrass at the two- to three-leaf stage was investigated in field experiments using some alternative configurations of nozzle mounting on the sprayer. Angling the spray either forward or backward relative to the direction of travel increased herbicide efficacy using standard commercially available flat-fan and pre-orifice nozzles. Efficacy increased generally with increasing angling relative to vertically downward and the forward-angled spray improved efficacy most. The largest improvement in efficacy was obtained using a 60° forward-angled spray in combination with a reduced boom height. Using this configuration, herbicide dose could be reduced by approximately 30% without loss of efficacy in comparison with the standard vertical mounting of nozzles. There was no advantage of using combinations of forward- and backward-angled nozzles. Nomenclature: Haloxyfop; perennial ryegrass, Lolium perenne L. LOLPE.
Article
The developments of information and automation technologies have opened a new era for weed management to fit physical and chemical control treatments to the spatial and temporal heterogeneity of weed distributions in agricultural fields. This review describes the technologies of site‐specific weed management (SSWM) systems, evaluates their ecological and economic benefits and gives a perspective for the implementation in practical farming. Sensor technologies including 3D cameras, multispectral imaging and Artificial Intelligence (AI) for weed classification and computer‐based decision algorithms are described in combination with precise spraying and hoeing operations. Those treatments are targeted for patches of weeds or individual weed plants. Cameras can also guide inter‐row hoes precisely in the centre between two crop rows at much higher driving speed. Camera‐guided hoeing increased selectivity and weed control efficacy compared with manual steered hoeing. Robots combine those guiding systems with in‐row hoeing or spot spraying systems that can selectively control individual weeds within crop rows. Results with patch spraying show at least 50% saving of herbicides in various crops without causing additional costs for weed control in the following years. A challenge with these technologies is the interoperability of sensing and controllers. Most of the current SSWM technologies use their own IT protocols that do not allow connecting different sensors and implements. Plug & play standards for linking detection, decision making and weeding would improve the adoption of new SSWM technologies and reduce operational costs. An important impact of SSWM is the potential contribution to the EU‐Green Deal targets to reduce pesticide use and increase biodiversity. However, further on‐farm research is needed for integrating those technologies into agricultural practice.
Article
A camera sensor for precision weed control in arable fields has been developed at the Leibniz Institute for Agricultural Engineering. For herbicide spraying in carrots, the sensor was positioned at the front three-point linkage of a tractor and was operated between carrot rows. In field trials in 2 years, real-time (online) technology in which sensing and spraying were performed in one step was evaluated in comparison with a conventional uniform spraying application. The spray volume was linearly adjusted to the camera-detected weed coverage level from a minimum of 200 L ha−1 if no weeds were present to a maximum of 400 L ha−1. The herbicide savings were 30% in 2007 and 34%, 43% and 36% for each of three applications in 2010. There were no significant differences between the camera-based and conventional spraying approaches with regard to yield parameters, total carrot weight and weight of marketable carrots. Regarding the weed control efficiency of the camera-based spraying procedure in the 2010 experiment, no trend was observed between the weed coverage and the application rate of the previous spraying.
Article
To reduce reliance on fungicides for disease control on oilseed rape, Decision Support Systems (DSS) are being developed to guide fungicide applications as part of an integrated pest and disease management strategy. This paper reports the development and uptake of an empirical model for prediction of risk of severe light leaf spot using disease survey and meteorological data to produce autumn regional and crop-specific prediction of epidemic risk for the following spring. Following initial delivery of the light leaf spot forecast via the farming press, an Internet-based interactive website was developed to provide crop-specific predictions. Uptake by growers, advisors and other members of the arable industry has been encouraging. There is evidence to suggest that growers and their advisors visit the website for an up-to-date prediction at the time when they are making fungicide application decisions.
Article
Weeds cause crop yield loss due to competition, interfere with agricultural activities and reduce grain quality due to seed contamination. Among the numerous methods for weed control, the use of herbicides is the most common practice. Nowadays, the optimization of herbicide application is pursued to reduce the environmental impact, delay the appearance of herbicide-resistant weed populations, and improve the cost/benefit ratio of the agronomic business. This work proposes an operational planning model, aimed at calculating the optimal application times of herbicides in no-tillage systems within a growing season in order to maximize the economic benefit of the activity while rationalizing the intensity of the applications with respect to expert-knowledge-based recommendations. The model can decide on herbicide applications on a daily basis, consistent with timing of agricultural activities, and provides an explicit quantification of the environmental impact as an external cost. The proposed approach was tested on a winter wheat (Triticum aestivum)–wild oat (Avena fatua) system, typical of the semiarid region of Argentina. In all the studied scenarios at least two pre-sowing applications of non-selective herbicides were required to effectively control early emerging weed seedlings. Additional pre-sowing and post-emergence applications were also advised in cases when competitive pressure was significant.
Article
Abstract Conservation agriculture (CA) has been suggested as a means of making intensification of agriculture sustainable. The purpose of this study was to understand and quantify long-term individual and combined effects of key conservation practices on soil physical properties and topsoil carbon content. Field experiments were conducted in 11- to 12-year-old experiments on two Danish sandy loams at Foulum and Flakkebjerg. Three crop rotations/residue management treatments were compared and tillage was included as a split-plot factor. The tillage systems were moldboard plowing to a depth of 20 cm (MP), direct drilling (D) and harrowing to a depth of 8-10 cm (H). Soil sampling and in-field measurements were carried out in autumn 2013 and spring 2014. In the field, soil structure was visually evaluated and penetration resistance measured. Soil carbon, wet stability (clay dispersion and wet aggregate stability), and soil strength were determined in the laboratory. The MP soil had a uniform soil organic carbon (SOC) content in the 0- to 20-cm topsoil, whereas H and D resulted in SOC accumulation near the soil surface. Plowing resulted in the best visually-assessed topsoil structure and had the lowest penetration resistance. However, H and D in combination with residue retention gave the best structural stability. Residue retention alleviated negative effects of reduced tillage on penetration resistance and improved wet stability in the MP treatment at the Foulum site. Clay and SOC correlated well with soil physical parameters, confirming their important role in soil structure formation and stabilization. Our study showed benefits of combining key CA elements, although longer-term studies are most likely needed to reveal the full potential. Keywords: rotation, conservation tillage, residue retention, soil quality, soil structure
Chapter
This chapter provides an up-to-date summary of the parameters influencing herbicide performance. It addresses the interaction between soil moisture and the performance of foliage-applied herbicides. Herbicides can be grouped according to different characteristics such as mode of action, site of uptake and mobility in the plants. Herbicides can be classified as either soil-applied or foliage-applied herbicides, reflecting whether the below-ground plant parts, that is, roots and the emerging shoot, or the above-ground plant parts such as leaves and stems are the main site of uptake. When studying the influence of biotic and abiotic factors on herbicide performance, the size of the displacement of the dose response curve provides more information and is of much more relevance than the difference in effect at a specific rate, and sub-lethal rates should therefore always be included in such studies.
Thesis
Full-text available
In recent years, precision agriculture and precision weed control have been developed aiming at optimising yield and cost while minimising environmental impact. Such solutions include robots for precise hoeing or spraying. The commercial success of robots and other precision weed control techniques has, however, been limited, partly due to a combination of a high acquisition price and low capacity compared to conventional spray booms, limiting the usage of precision weeding to high-value crops. Nonetheless, conventional spray booms are rarely used optimally. A study by Jørgensen et al. (2007) has shown that selecting the right herbicides can lead to savings by more than 40 percent in cereal fields without decreasing the crop yield when using conventional sprayers. Therefore, in order to utilise conventional spray booms optimally, a preliminary analysis of the field is necessary. This analysis should determine which weeds are present in the field and the density of those weeds so that herbicides targeting those weeds may be selected. Researchers have sought to detect and classify weeds and crops in images, but studies are limited regarding the number of plant species that can be discriminated and the flexibility of the camera setup. In the present PhD thesis, requirements for the camera set-up are loosened, allowing the use of consumer grade cameras or even cell phones for weed species localisation and identification in images from conventionally grown fields. In total 4 537 images have been collected over three growth seasons from Danish fields. In these images 31397 plants are annotated with names, from which the 17 most frequent species are selected for automated classifiiiication. The automated classification consists of two steps: Initially, weeds are located in images after which, the weeds are classified. Three types of weed localisation approaches are tested: Two approaches that perform a pixel-wise segmentation of plants, and one approach, that detects regions in images containing weeds. Common for all three approaches is that they aim at overcoming some of the challenges when working with images from fields: Namely changes in lighting, soil types, and plant stress due to lack of nutrition. The first of the suggested approaches segments plant material from the soil by using fuzzy C -means clustering combined with a threshold value for each pixel, which depends on the neighbourhood pixels, which helps to detect non-green stem regions. The second approach uses a fully convolutional neural network for segmenting pixels in three categories: Soil, weeds, and crops. The Neural Network is trained solely on modelled images but can segment weeds from maize with an intersection-over-union of between 0.69 and 0.93 for weeds and maize. Rather than segmenting images, the third approach produces region proposals that indicate weed locations in images. This method also uses a fully convolutional neural network, that enables it to detect weed instances in wheat fields despite occluding leaves. The three methods for weed segmentation and localisation solve four problems in the field of camera based weed detection: handling of changing environments, handling of non-green plant stems, segmentation of weeds and crops that are overlapping, and instance detection in cereal fields with occluding leaves. Following the detection of the weeds, the weed species are to be determined. For solving this problem, a convolutional neural network is used, which classifies the weeds with an overall accuracy of 87 percent for 17 species despite a severe degree of leaf occlusion. Because of the ability to handle weed detection and classification in natural environments, these methods can potentially reduce the investment of farmers, and thus lead to a higher adoption rate than existing precision weed control techniques, resulting in huge potential savings regarding herbicide consumption.
Article
Weed emergence time and the longevity of weed seeds within the soil play an important role in implementing a timely and effective weed control program. In this study, the seed longevity and emergence pattern of wild oat ( Avena fatua L.) and sterile oat [ Avena sterilis ssp. ludoviciana (Durieu) Gillet & Magne] were monitored in field conditions. Fresh seeds of A. fatua and A. ludoviciana were placed into nylon bags (50 seeds per bag in three replications for three locations in Southeast Australia: Gatton, Narrabri, and St. George) and buried at depths of 0, 2, and 10 cm in November 2017. Bags were exhumed at 6-mo intervals over 30-mo to evaluate seed germination, viability, and decay components. The seed decay component of A. fatua and A. ludoviciana followed an exponential pattern. On both the surface and at the 10 cm burial depth, 50% of the seeds of A. fatua and A. ludoviciana had decayed by 6-mo. The seeds of A. fatua persisted longer at 2 cm depth than at other depths, particularly at St. George where 90% of the seeds decayed after the 30-mo study. However, at Gatton and Narrabri, 90% of the seeds of A. fatua at this depth had decayed after 18-mo of seed placement in the soil. In the emergence pattern experiment, the emergence of A. fatua and A. ludoviciana from different burial depths was also studied (2017-2019). The emergence of A. fatua and A. ludoviciana was greater from 2 cm (29-36%) and 5 cm (18-43%) soil depths compared to the surface (5-10%) and 10 cm (3-9%) soil depth. A. ludoviciana emerged earlier (2253 growing degree days, GDD; March 14, 2018) than A. fatua (3364 GDD; May 23, 2018). Both species exhibited high emergence between May to June 2018, and the last cohort of each species was observed in October 2018. The highest seedlings emergence occurred at the start of the winter season (May), which emphasizes the need for early PRE weed control such as tillage, herbicide application, and cover crops to ensure crops are planted in a clean seedbed. The continued emergence of these weeds into the spring season (October) emphasizes the need for extended periods of A. fatua and A. ludoviciana management. The results also suggest that management strategies that can control all emerged seedlings over two years and restrict seed rain in the field could lead to complete control of Avena spp. in the field.
Article
The possibility of combining novel monitoring techniques and precision spraying for crop protection in the future is discussed. A generic model for an innovative crop protection system has been used as a framework. This system will be able to monitor the entire cropping system and identify the presence of relevant pests, diseases and weeds online, and will be location specific. The system will offer prevention, monitoring, interpretation and action which will be performed in a continuous way. The monitoring is divided into several parts. Planting material, seeds and soil should be monitored for prevention purposes before the growing period to avoid, for example, the introduction of disease into the field and to ensure optimal growth conditions. Data from previous growing seasons, such as the location of weeds and previous diseases, should also be included. During the growing season, the crop will be monitored at a macroscale level until a location that needs special attention is identified. If relevant, this area will be monitored more intensively at a microscale level. A decision engine will analyse the data and offer advice on how to control the detected diseases, pests and weeds, using precision spray techniques or alternative measures. The goal is to provide tools that are able to produce high-quality products with the minimal use of conventional plant protection products. This review describes the technologies that can be used or that need further development in order to achieve this goal.
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