Indicators of weed competition on Organic Winter Wheat

Organic winter wheat production is limited by climatic and agronomic factors, including weed competition. The incidence of weeds on yield limitation can be characterized through various early indicators to predict weed occurrence and competition. A network of 10 fields of organic winter wheat was implemented in the South East of France in 2005-2006. Results showed that weed density, dynamics and diversity are good indicators for weed occurrence and competition

Improvement of the soil-crop model AZODYN under conventional, low-input and organic conditions

The use of mechanistic crop modelling, simulating the dynamics of crop N requirements and nitrogen supply from the soil and fertilizers, can provide sound advice to users. This paper describes a methodological way to improve soil-crop modeling used for N management of conventional and organic wheat

Effects of crop management and surrounding field environment on insect incidence in organic winter oilseed rape (Brassica napus L.)

Many organic farmers hesitate to grow winter oilseed rape (WOSR), despite its usefulness for crop rotations and animal fodder, because it is attacked by many insects, which are difficult to control without chemical treatments. In a geographically broad network of farmer’s fields, we analysed the effect of various crop management factors and of the surrounding field environment on a large range of insects known to damage WOSR: root maggot (Delia radicum L.), cabbage stem flea beetle (Psylliodes chrysocephala L.), rape stem weevil (Ceuthorhynchus napi Gyl) and pollen beetle (Meligethes aeneus F.). Our results confirm the effect of sowing date, plant density and soil tillage regime on root maggot attacks and cabbage stem flea beetle larva infestation. Early sowing tended to increase root maggot damage whereas it was associated with a lower level of attack of cabbage stem flea beetle. High plant density tended to decrease the damage or the attack of all insects. We show that nitrogen availability in the soil affect cabbage stem flea beetle, stem weevil levels and pollen beetle damage: the negative effect of soil nitrogen content on pollen beetle damage may be related to the significant effect of nitrogen on plant vigour and, therefore, to the compensation of pollen beetle damage on new racemes. If all insects were considered together, the proportion of land under WOSR in the region and the surrounding environment had a significant effect on pest occurrence. In regions with a high proportion of land under WOSR, the proportion of plants attacked by root maggot and pollen beetle tended to increase. Conversely, regions with high proportions of land under WOSR tended to have a smaller proportion of plants with cabbage stem flea beetle larvae or damage, whatever the environment surrounding the field. For almost all the pests considered, the fields displaying the most severe pest attacks in regions with more than 1.2% WOSR were bounded by trees, hedges and bushes. Conversely, in regions with a lower percentage of land under WOSR, woodland around the field reduced the occurrence of pest attack

How farmers perceive perennial weeds in Northern France and Eastern Germany

European farmers are required to follow the transition towards sustainable agriculture and food systems. Perennial weed management without chemical herbicides and inversion tillage is challenging farmers. Questions arise to cope with these spreading weeds. Our study focuses on farmers’ perceptions and experiences of perennial weeds and their control in Northern France and Eastern Germany. A survey was developed to explore the situation regarding present concerns and future problems for perennial weed control. The survey conducted from winter 2020/21 to spring 2021 targeted conventional, conservation and organic farms. We found a high level of awareness for perennial weeds. On average, 80.0% of Northern French farmers and 65.9% of Eastern German farmers revealed present concerns about perennial weeds. Both, Northern French and Eastern German farmers perceived perennial weeds are more damaging to crop production than other pests. In both regions, the farmers considered Cirsium arvense (L.) Scop. as the most important perennial weed. While the majority of the Eastern German farmers observed field infestations of Elymus repens (L.) Gould, Northern French farmers more often reported Sonchus arvensis L. infestations. More than 50% of the farmers stated Rumex spp. infestations in Northern France and Eastern Germany. Interestingly, Eastern German farmers are more concerned about future perennial weed problems than Northern French farmers. The reasons for farmer’s future concerns are probably connected to the farming system. In both regions, conservation and conventional farmers heavily rely on herbicides for perennial weed control, however, more farms used the active ingredient glyphosate in Eastern Germany. Nonetheless, perennial weed control is a major concern for organic farmers in both regions. We conclude that optimizing and integrating non-chemical alternatives is promising in all farming systems. Research activities are required to provide farmers and extension services with novel and profitable perennial weed management practices

Future management of arable perennials - an introduction to the project AC/DC-weeds

Mehrjährige Wurzelunkräuter beeinträchtigen die ackerbauliche Produktion. Verbreitete Bekämpfungspraktiken sind intensive wendende Bodenbearbeitung und chemisch-synthetische Herbizide. Diese gebräuchlichen Methoden haben allerdings unerwünschte Effekte auf Nicht-Ziel-Organismen und die Umwelt. Ziel des SusCrop-ERA-NET geförderten Europäischen Projekts ‘AC/DC-weeds’ ist es, agrarökologisch basiertes Management von mehrjährigen Wurzelunkräutern zu etablieren. Beiträge zur Reduktion von wendender Bodenbearbeitung in ökologischen und konventionellen Ackerbau und dem Ersatz von Glyphosat in letzterem zu liefern, sind die übergeordneten Aufgaben. Getragen von sieben Partnern aus fünf europäischen Ländern läuft das Projekt von 2019 bis 2022. Drei wichtige mehrjährige Arten in Nord- und Zentral-Europa werden fokussiert (Sonchus arvensis, Cirsium arvense und Elymus repens). Zu diesen Arten erfasst AC/DC-weeds Ökologie und Wirkungen des agronomischen Managements mit Experimenten und einer systematischen Literatur-Recherche. Neues agrar-ökologisches Managements der Arten wird in Feldversuchen und Semi-Feld Versuchen untersucht. Für die Erfassung werden innovative Technologien eingesetzt, um der nesterweisen Verteilung im Feld gerecht zu werden. Qualitative Modelle nutzen Wissen zu den Einflussfaktoren auf das Vorkommen von mehrjährigen Unkräutern, um sie für Entscheidungen nutzbar zu machen. Das Wachstum der Arten und die Effekte des Managements werden einfach und grafisch in einer Web-Anwendung visualisiert. Die Versuche und Modellierungen werden begleitet durch eine Umweltbewertung- und ökonomische Kalkulationen.Creeping perennial weeds have strong negative impacts on arable production. The common control practices are intensive inversion tillage and chemical herbicides. However, these traditional methods negatively affect non-target species and the environment. The objective of the SusCrop-ERA-NET funded European project ‘AC/DC-weeds’ is to implement agro-ecological management for creeping perennials in arable farming. The overall aim of this project is to reduce plough-tillage in organic and conventional farming, and to replace glyphosate in the latter system. From 2019 to 2022, this project involves seven partners from five European countries. Focusing on three important perennial species in central and northern Europe (Sonchus arvensis, Cirsium arvense and Elymus repens), AC/DC-weeds will thoroughly study the ecology and agronomical management of these species through systematic literature reviews and experiments. Novel agro-ecological management of these species is examined in field experiments and semi-field approaches. Innovative technology will be used to identify and monitor the distribution of these weeds on fields. Qualitative models are developed to make use of existing knowledge and expertise of the influences on perennial infestations in management decisions. A graphic web tool will enable visualization of the growth of the species and the effects of weed management. Environmental and economic evaluations on different weed management accompany the experimental and modelling work

Multi-scale studies of the relationships between cropping structure and pest and disease regulation services

International audienceThe early detection of DNA mutations such as DNA mismatches is of major interest. Indeed, the accumulation of mismatches into the genome arises from deficiencies of the cellular mismatch repair machinery that is often associated with several types of cancers being resistant to classic chemotherapeutics. In this context, ruthenium(II) compounds bearing a planar extended ligand appear to be excellent candidates as DNA photoprobes since they exhibit high affinity for DNA as well as tuneable luminescence properties. Herein, we report on the synthesis of a novel dissymmetric acridine based Ru(II) complex, [Ru (bpy) 2 napp] 2+ , along with the study of its ability to photodetect DNA mismatches. We also investigated the origin of the ability of the complex to photodetect mismatches via CD-melting assays and bio-layer interferometry. Interestingly, this behaviour may be attributed to a better protection of the excited state of the complex from non-radiative deexcitation sources (e.g., collisions with the solvent, oxygen photosensi-tization, etc.) when intercalated into well-matched compared to mismatched DNA

Lokalmeteorologiska förhållanden i Västra Ängby, Knivsta : förstudie /

<p>Variation of pollen beetle abundance along within-field (A) and between-field (B) transects as a function of distance (km) to woodland edges. (A) Number of pollen beetles per sampling point within two different OSR fields (fields in complex site, C). (B) Mean number of pollen beetles per field in three transects (in zones S, for simple landscape, and HC, for highly complex landscape). Abundance were measured on 10 OSR plants at each sampling point during three (A) or four (B) consecutive weeks (dates 1 to 4). Trans: Transect.</p

Agroecosystem management and biotic interactions: a review

Increasing the use of synthetic fertilisers and pesticides in agroecosystems has led to higher crop yields, accompanied by a decline in biodiversity at the levels of field, cropping system and farm. Biodiversity decline has been favoured by changes at landscape level such as regional farm specialisation, increases in field size, and the removal of hedgerows and woodlots. The loss of biodiversity in agroecosystems has increased the need for external inputs because beneficial functions are no longer provided by beneficial species as natural enemies of crop pests and ecosystem engineers. This trend has led to a strong reliance on petrochemicals in agroecosystems. However, many scientists have been arguing for more than two decades that this reliance on petrochemicals could be considerably reduced by a better use of biotic interactions. This article reviewsoptions to increase beneficial biotic interactions in agroecosystems and to improve pest management and crop nutrition whilst decreasing petrochemical use. Four agronomic options are presented. First, it has been shown that the choice of cultivar, the sowing date and nitrogen fertilisation practices can be manipulated to prevent interactions between pests and crop, in either time or space. Nevertheless, the efficacy of these manipulations may be limited by pest adaptation. Second, beneficial biotic interactions may result from appropriate changes to the habitats of natural enemies and ecosystem engineers, mediated by soil and weed management. Here, knowledge is scarce, and indirect and complex effects are poorly understood. Third, changes achieved by crop diversification and, fourth, by landscape adaptation are promising. However, these practices also present drawbacks that may not necessarily be outweighed by beneficial effects. Overall, these four management approaches provide a powerful framework to develop sustainable agronomic practices

Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies