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The aim of this communication is to present the landscape agronomy framework and how it addresses spatially explicit natural resource management in agriculture. Based on a summary of the scientific background and state of the art on how agriculture is addressed at the landscape level, the result is a conceptual model that provides a framework for observing, understanding, and supporting the actions of actors involved in the dynamics of agricultural landscapes and the design of agri-food systems. The landscape agronomy conceptual model was developed to integrate assessment and monitoring beyond the farm level and across multiple temporal and spatial scales. It was introduced in a seminal paper by Benoît and colleagues (Landscape Ecology, 27(10):2012), which highlighted the importance of an integrated approach to describing and understanding farming practices, natural resources, and landscape patterns. The landscape agronomy conceptual framework is intended to help understand what may be missing to achieve landscape agroecological transitions and to guide the design of research, education and training by raising awareness about the components and relationships of a system approach to agriculture., Projet n° ANR-22-CPJ1-0050-01 Chaire de Professeur Junior IRD en Géoagronomie

19thEuropean Weed Research Society Conference, Athens, Greece, 20-23 June 2022 This work raises the questions, is the relay intercropping of subsidiary legumes with durum wheat a sustainable intercropping practice from an economic point of view? Which subsidiary legume among Medicago sativa, Trifolium repens, Hedysarum coronarium, Medicago lupulina, Trifolium incarnatum, Trifolium resupinatum; Trifolium subterraneum, and Medicago polymorpha maximize the profitability of relay intecropping in a low-input cereal based Mediterranean cropping system? Therefore, an assessment was performed to evaluate the economic sustainability of several subsidiary legumes for relay intercropping with durum wheat, taking into account the impact of legumes on the co-cultivated wheat and to the subsequent forage sorghum. A 2-years plot experiment was carried out in Pisa (Tuscany) in a complete randomized block design with 4 replications. Legumes were sown in the already established wheat in late winter. After the wheat harvest legumes were maintained in the field until the subsequent spring and incorporated into the soil by plowing. Forage sorghum was sown for the evaluation of the residual effects of each legume on the subsequent crop. Gross Income (GI) was calculated for wheat and sorghum as the difference between the Gross Production Value (GPV) and the total production costs (C). The overall economic impact of relay intercropping in a wheat-sorghum rotation was estimated by the calculation of the cumulative GI. Results of this study reveal that relay intercropping reduces profitability of the co-cultivated durum wheat because the productive advantages do not cover the additional costs due to the inter-sowing operations. After the wheat harvest the presence of legumes in the field ensure a good weed control and potentially allows to reduce tillage and herbicides application with an estimated save of 195 €/ha compared to the conventional management. The gross income of sorghum preceded by these legumes is higher compared to the control and it can be up to 955 €/ha. According to the legume choice, relay intercropping of legumes demonstrated to satisfy nutritional requirements for the subsequent sorghum and allows to reduce the input costs up to 253 €/ha. H. coronarium and T. repens were identified as the best performing legumes from an economic point of view. For these legumes the costs due to the relay intercropping were balanced by the ecosystem services that they provide at crop rotation level.

The increased interest in sustainable agricultural systems has led to significant developments in cropping practices that allow to preserve crop productivity and reduce the reliance on herbicides and nitrogen fertilizers. Relay intercropping of legumes in wheat may represent a proficient practice to maintain crop productivity, improve soil fertility and support weed control at crop rotation level, if appropriate associated legumes are used. The objective of this study is to select suited legumes for relay intercropping with durum wheat in central Italy among a wide range of taxa (Medicago sativa, Medicago varia, Medicago lupulina, Trifolium repens, Hedysarum coronarium, Trifolium alexandrinum, Trifolium incarnatum, Trifolium resupinatum, Vicia villosa, Medicago polymorpha, Medicago rotata, Medicago scutellata, Medicago truncatula, and, 3 subsp. of Trifolium subterraneum). This study was carried out at the Centre for Agro-Environmental Research “Enrico Avanzi” in Pisa (Italy) in 2017/18 and repeated in the 2018/19 cropping season. According to the results obtained during 2017/18, legumes were reduced in 2018/19 excluding the least performing ones. The experiment was organized in a randomized complete block design with four replicates and the sole wheat crop as control. No pesticides or fertilizers were used. The evaluation was focused on i) legume establishment in the already developed wheat, ii) grain production and quality, iii) weed control before and after the wheat harvest, iv) legume persistence and growth after wheat harvest and, v) effects on the following crop. Legumes, indeed, were incorporated into the soil the following spring and forage sorghum was seeded. Results of this study showed that relay intercropped legumes preserved wheat production and reduced weed biomass up to the 70% in comparison with the control. After wheat harvest legumes persisted in the field, as dead mulch or cover crop according to the different life cycle of the tested legumes, until the sowing of sorghum. Dead mulch of annual legumes resulted unsuitable to contrast weeds while, perennial and annual self-seeding legumes as M.polymorpha and T.subterraneum, showed overall good weed control and biomass accumulation. Legume biomass at spring soil incorporation, was the most important factor related with sorghum production. Sorghum, preceded by T. subterranum, H. coronarium and T. repens, had a higher biomass production than the control and was comparable with the productive level that can be obtained under conventional systems. The overall assessment of legumes used in this study, allows to select the most suited ones for relay intercropping with durum wheat for the local environmental condition.

International audience

We would like to change the authors’ names and email addresses on page 195 of paper [1] from: John M. Holland 1,*, Philippe Jeanneret 2, Anna-Camilla Moonen 3, Wopke van der Werf 4, Walter A.H. Rossing 5, Daniele Antichi 6, Martin H. Entling 7, Brice Giffard 8, Herman Helsen 9, Mark Szalai 10, Carlo Rega 11, Caroline Gibert 12 and Eve Veromann 13 1 Farmland Ecology Unit, Game and Wildlife Conservation Trust, Fordingbridge SP6 1EF, UK 2 Agroecology and Environment, Agroscope, CH-8046 Zurich, Switzerland; philippe.jeanneret@agroscope.admin.ch 3 Scuola Superiore Sant’Anna, Agroecology Group, Institute of Life Sciences, Via Santa Cecilia 3, 56127 Pisa, Italy; moonen@sssup.it 4 Wageningen University & Research, Crop Systems Analysis, Droevendaalsesteeg 1, 6708PBWageningen, The Netherlands; wopke.vanderwerf@wur.nl.

The objective of this experiment is to screen perennial and annual self-reseeding legumes cover crops for investigating their potential role as permanent living mulch in organic vegetable systems. This study focuses on the screening of legumes based on their morphology, phenology and weed suppression capacity. This is the first phase of a trial in which 28 different legume cover crops are tested as sole crop in order to select the most interesting ones for the local environmental condition. A reduced number of selected legumes will then be tested as permanent living mulch in a vegetable cropping system. Both perennial and annual self-reseeding legumes may be suitable for the target system. Perennial legumes are expected to exert weed control all over the year as living mulch. Annual self-reseeding legumes are able to re-generate from the soil seed bank in autumn and therefore improve weed control during winter as living mulch, while during summer they act as dead mulch, hence limiting the potential water competition during this season. This preliminary experiment was necessary because one of the main challenges to establish successfully a permanent living mulch is the appropriate choice of legume species and/or varieties. Indeed, specific morphological, physiological and phenological traits are crucial in order to obtain the benefits of living mulch and avoid over-competition with the main crop (Ciaccia et al., 2017). Unfortunately, the availability of suitable legumes for this system seems limited, because the cultivars available on the market are normally selected for other uses, e.g. high biomass production and, hence, they are likely highly competitive with the main crop. A specific legume ideotype selection is therefore necessary.