Can Shading Affect Nitrogen Fixation Of Forage Legume Swards? An Assessment Of B-Value Through The 15N Natural Abundance Method

Tree-based intercropping systems are gaining pace as a land-use strategy to cope with climate change and provide environmental, economic, and social benefits. The integration of nitrogen-fixing crops between trees can be a solution to increase the land productivity and reduce the reliance on external inputs by increasing nitrogen (N) availability and then both tree and crop growth. Intercropping perennial legumes with trees can also reduce nitrogen losses, due to the higher amount of N accumulated in stable forms in the soil due to biological N₂-fixation and N root compartimentation. On the other hand tree competition for light, water and nutrients eventually could limit legume growth and N₂-fixation. The isotopic method based on ¹⁵N natural abundance is one of the most used methods to assess Biological Nitrogen Fixation (BNF). The B-value, that is defined as the δ¹⁵N value of a legume when completely dependent on N₂-fixation for satisfying its N demand, is of primary importance for BNF estimations. The B-value may vary with species, plant age at harvest and growing conditions, e.g. light availability. Therefore, the B-value found in literature could not be representative for all legumes and environments, in particular for legumes grown intercropped with trees and thus subject to shading conditions. In this pot experiment we assessed the B-value of several forage legumes, as affected by different levels of simulated shading and grown in N-free medium. A greenhouse pot experiment was established in March 2021 at the Department of Agriculture, Food and Environment (DAFE) of the University of Pisa to determine the B-value for ¹⁵N calculations about two forage legume species grown in a field trial located at the Center of Agri-Envirnomental Research “Enrico Avanzi” of the University of Pisa, San Piero a Grado (Pisa) (43°41'6.97"N 10°20'29.22"E), using the same shade treatments

Light reduction affected agronomic performance and nutritive value of temporary grassland swards in a Mediterranean rainfed plot trial

In Italy, traditional olive orchards are characterised by low tree density (100-300 ha-1) allowing the cultivation of forage and crops under the tree canopy (Paris et al., 2019). Eichhorn et al. (2006), reported that in Central Italy there are 20000 ha of farmland identified as a silvoarable olive orchard. The intercropping of perennial legumes and trees is a key strategy to improve nutrient cycle of silvoarable systems, due to the higher amount of nitrogen (N) accumulated in stable forms in soil due by biological nitrogen-fixation (Hernandez-Esteban et al., 2019; Sanna et al., 2019), leading to a request for reduction of inorganic N fertilisation. Perennial legumes can also provide a continuous soil cover during the entire year reducing soil loss risk (Vallebona et al., 2016). In the Mediterranean basin, the most important perennial legume is alfalfa (Medicago sativa L.). Previous studies reported that alfalfa nutritive value was not negatively affected by tree presence (Mantino et al., 2021), whereas legume production was reduced due the competition for resources such as water (Nasielski et al., 2015), nutrients (Isaac et al., 2014) and light (Mantino et al., 2021). In Tuscany, sulla (Hedysarum coronarium L.) an autochthonous biennial legume is appreciated for its rusticity, productivity, and quality and it is intercropped with Italian ryegrass (Lolium multiflorum Lam.) for a better utilisation as pasture. In 2019, a rainfed field plot trial was established to evaluate agronomic performance and nutritive value of different perennial forage species grown under different levels of light reduction, aiming to start a selection of shade tolerant forage crops. In October, the plot trial was established in Pisa, on a clay-loam soil with pH of 8.1 and 2.5 % w/w of organic matter content in the topsoil (0-0.3 m). Before sowing, 100 kg ha-1 of P2O5 were applied. The experimental layout complies with a two-factor randomized complete block design with four replicates (18 m2 sizing each plot). The first factor included five different swards: i) sulla cv. Silvan, (ii) ryegrass cv. Teanna, (iii) mix of sulla cv. Silvan and ryegrass, 50:50 (iv) mix of sulla cv. Silvan, sulla cv. Chiara Stella and sulla cv. Bellante 33:33:33 and (v) alfalfa cv. Messe. The second factor included three increasing shading levels: S0) the control representing full light availability, S25) and S50), corresponding to a reduction of potential light availability of 25 and 50% respectively. As previously tested by Varella et al. (2011), shading was provided by woody slats, N-S oriented, 2.0 m long and 0.10 m wide, with a distance between each slat of 0.10 m for S50 and 0.20 m for S25, covering a total surface of 4 m2. After sowing, slats were placed at 0.8 m above ground level. Yield and nutritive value of herbage mass and N2 fixation were evaluated for two consecutive years. Herbage biomass was not affected by the reduction of the 50% of light in ryegrass and ryegrass-sulla mixture while it was negatively affected in alfalfa and sulla. Conversely, the 25% of shade level had no effect on legume yield

Simulating the effect of climatic variations on the long-term performance of different agroforestry systems within field trials using virtual experiments

Agroforestry systems can reduce some of the adverse effects of climate change in agriculture by e.g. serving as a windbreak or shade provider to protect crops or grazing livestock and supporting beneficial species for pest control. The prediction of the long-term performance of different agroforestry options is however difficult to obtain through field quantify experiments due to the length of time trees grow for experiments. Numerical modelling can contribute to a better understanding of a system’s performance, since the effect of different climatic alterations can be tested using virtual experiments for different periods of time. Within the Horizon 2020 AGROMIX project, we are analysing the long-term performance of eight different agroforestry trials (Figure 1), using different modelling approaches. The trials are spread over three biogeographic regions (Mediterranean, Continental, and Atlantic) and are of varying age (4 to 33 years). In total, six silvoarable and five silvopastoral farming systems are maintained at the eight field trials. Through the use of different numerical models the effect of changes in temperature and precipitation patterns or the occurrence of extreme events such as droughts or late spring frost on the different agroforestry systems will be predicted. Additionally, experimental data on crop performance as well as animal behaviour and welfare, in particular under heat stress, are being obtained and will potentially be included in the model predictions. This poster aims to give an overview on the field trials and the numerical modelling approaches that are being applied to predict long-term system performance

Effetto combinato di colture di copertura, fertilizzazione azotata, e tecniche di lavorazione del terreno sulla fertilita chimico-fisica del suolo

l’impoverimento della fertilità dei terreni, l’inquinamento della maggior parte degli agroecosistemi, la riduzione della salubrità degli alimenti, e l’aumento delle emissioni di gas serra (GHG) responsabili del riscaldamento globale, negli ultimi 30 anni hanno causato una sensibilizzazione degli addetti al settore, della comunità scientifica e dell’opinione pubblica al riguardo. Questo ha portato allo sviluppo di sistemi agricoli più sostenibili per l’ambiente, che garantiscano delle rese produttive sufficienti, ma con l’obbiettivo principale, di aumentare la fertilità del suolo, considerata il bene principale da cui dipende il successo delle colture. Un esempio sono l’Agricoltura Biologica, che tra i suoi principi cardine ha il divieto di utilizzare composti chimici di sintesi, e l’Agricoltura Conservativa, che si basa sull’utilizzo ridotto di input esterni, soprattutto per quanto riguarda le lavorazioni del terreno. Entrambi i sistemi per aumentare la biodiversità, e la fertilità del terreno, danno un’elevata importanza all’utilizzo delle cover crops (colture di copertura), cioè, colture intercalari che si utilizzano tra due colture principali per mantenere il terreno coperto ed evitare la mineralizzazione spinta della sostanza organica (SOM, soil organic matter). Queste colture a fine ciclo vengono devitalizzate e lasciate sul terreno come pacciamatura morta (dead mulch), permettendo una migliore ritenzione idrica, minore erosione e mineralizzazione della SOM ecc., o vengono sovesciate (green manure) andando ad aumentare la SOM, il carbon-stock, la disponibilità di nutrienti, con effetto anche ammendante. Lo scopo della tesi è stato quello di osservare gli effetti dovuti al variare della coltura di copertura, della tecnica di lavorazione e della concimazione azotata sulla fertilità chimica e fisica del suolo, in una prova di lungo periodo della durata di 23 anni. L’ipotesi di partenza sulla base della letteratura consultata, è che l’applicazione ripetuta nel tempo della non lavorazione, coadiuvata all’apporto costante di biomassa vegetale, determini un incremento della SOM, influenzando a cascata anche altre caratteristiche del suolo, come ad esempio la struttura e la ritenzione idrica. Nel caso in cui venga utilizzata regolarmente l’aratura si ha un impoverimento spinto del suolo, soprattutto se non coadiuvata dall’interramento dei residui colturali. Inoltre si ipotizza che l’apporto di azoto minerale vada indirettamente ad influenzare in modo positivo la SOM e Ntot mediante un maggiore apporto di biomassa al suolo. La prova è stata effettuata andando a indagare non solo la porzione superficiale del suolo, ma arrivando a campionare fino a 60 cm di profondità, così da poter valutare gli effetti delle pratiche già citate, su strati del terreno sui quali è più difficile fare delle previsioni. La ricerca di lungo periodo è iniziata nel 1993 presso il Centro di Ricerche Agroambientali “Enrico Avanzi” dell’Università di Pisa, situato a San Piero a Grado (PI), e ad oggi è ancora in corso. Il disegno sperimentale è di tipo split-split-plot a quattro replicazioni, e non è mai stato modificato dall’inizio della prova: fattore principale-2 livelli di lavorazione; fattore secondario-4 livelli di fertilizzazione azotata; fattore terziario-4 livelli di cover crops. Data la natura particolarmente complessa del disegno sperimentale, le indagini si sono limitate ad un numero di tesi inferiore al totale (12 su 32), cioè quelle oggetto dei seguenti trattamenti: lavorazioni-CS (sistema convenzionale) e LIS (sistema low-input); fertilizzazione azotata-N0 e N2; colture di copertura-C (controllo, assenza di cover crops), Vv (Vicia villosa), e BJ (brassica juncea). Ogni parcella elementare ha una superficie di 210 m2 (21 × 11 m). In totale le parcelle campionate sono state 48. In ogni parcella è stato effettuato un campionamento a tre profondità (0-10 cm, 10-30 cm, 30-60 cm) in due subrepliche. In totale i campioni di terreno analizzati sono stati 288: 48 parcelle × 3 profondità × 2 subrepliche. L’indagine sperimentale ha interessato i seguenti parametri chimici e fisici del terreno: pH, SOM, Ntot (azoto totale), Pass (fosforo assimilabile), densità apparente. Il confronto dei dati ottenuti da questa analisi sperimentale con le serie storiche ha fornito un quadro d’insieme dell’influenza dei fattori agronomici sull’agroecosistema, così da poter individuare le combinazioni di tecniche colturali che risultano più efficaci per il mantenimento o il miglioramento dei principali parametri della fertilità chimica, fisica e biologica del terreno. Dopo avere analizzato i dati relativi al tipo di lavorazione, è stato osservato che la SOM% nello strato superficiale di terreno (0-10 cm) cresce in modo netto con LIS ed è stabile con CS. Negli ultimi 4 anni si è evidenziata una crescita della SOM% a favore di LIS anche nello strato 10-30 cm, così che complessivamente per l’intero strato 0-30 cm è risultato un netto vantaggio nell’utilizzo delle lavorazioni ridotte. Per quanto riguarda la dose di fertilizzante azotato, si è osservato un effetto meno marcato nell’aumento della SOM%, da mettersi in relazione con l’aumento della biomassa dei residui colturali e delle piante infestanti che ritornano al terreno. Rispetto al testimone privo di colture di copertura, le cover crops, in particolare la veccia, hanno contribuito ad aumentare la SOM% nello strato 0-10 cm in modo più evidente all’interno dei sistemi LIS e in assenza di concimazione minerale, anche se in misura ridotta rispetto agli anni precedenti. Complessivamente su tutto il profilo osservato (0-60 cm) tra LIS e CS c’è sempre un vantaggio da parte del LIS su tutti e tre i fattori considerati. Le differenze maggiori si hanno nello strato più superficiale (0-10 cm), più blande ma comunque evidenti nello strato 10-30 cm, e non significative nello strato 30-60 cm. In conclusione si conferma quanto evidenziato dalla letteratura, ma si osservano in aggiunta dei miglioramenti nella SOM% anche negli strati più profondi, nello specifico tra 10 e 30 cm, rivelando una stratificazione più estesa del C lungo il profilo. Inoltre, anche se a 30-60 cm non si notano differenze significative tra i due sistemi, se i dati vengono mediati sull’intero profilo, la SOM% ha comunque mostrato un livello maggiore nel LIS rispetto al CS, contrariamente a quanto riportato in letteratura da numerosi autori. Inoltre dall’analisi dei dati risulta che, a distanza di 23 anni, nel LIS la SOM% non ha ancora raggiunto un nuovo equilibrio, ma è ancora in crescita costante. Il raggiungimento dell’equilibrio si ipotizza in circa 30 anni, come riportato nella letteratura, rendendo possibili ulteriori margini di miglioramento della fertilità del terreno

Transition to agroecological management of forage-based cropping systems in the Mediterranean area

Agroforestry is considered an agroecological strategy with the potential to reduce nutrient leaching, conserve soils, increase diversity of the production system, and produce complementary wood for various uses. This practice is gaining pace as a land use strategy to cope with climate change and deliver important ecosystem services with an impact on crop productivity and reduction of agri-environmental risks. To achieve the goal of reducing the global warming potential of the agricultural sector, it is also of pivotal importance to reduce the reliance of agricultural systems on non-renewable external inputs, such as inorganic nitrogen (N) fertilizers. Agroforestry systems (AFS) including legume crops, and especially perennial forage legumes, can be considered a sustainable approach to enhance N cycling and use efficiency, thanks to the high amount of N supplied by biological N2-fixation and stored in stable forms in the soil. Moreover, perennial legumes can supply a permanent soil cover during the whole year, thus reducing soil erosion and nitrate leaching. Nevertheless, to design sustainable and productive agroforestry systems, net responses of crops to trees need to be clarified, especially in regions, like the Mediterranean area, where competitive interactions for water and nutrients usually prevail. This thesis reports results about the application of agroecological practices such as the (i) use of perennial forage legumes, (ii) forage crop mixtures, (iii) real and simulated agroforestry conditions with the purpose of identifying new key management strategies for farmers to approach the agroecological transition to AFS. In particular, this work focused on forage-based cropping systems under Mediterranean and rainfed conditions. The two field experiments object of this thesis were carried out at the Center for Agri-Environmental Research “Enrico Avanzi” of the University of Pisa, in a typical coastal plain area of Tuscany, Central Italy. The first field plot trial was carried out to assess the agronomic and qualitative performance of both, cool-season and warm-season perennial forage legumes and a cool-season grass sward, grown under diverse levels of artificial shade (i.e., 30%, moderate shade; 50%, intense shade). Regarding legume crops, specific analyses on biological N2-fixation (BNF) were conducted. Considering cool-season legume and grass species, i.e., sulla (Hedysarum coronarium L.), ryegrass (Lolium multiflorum Lam.) and their mixture, results showed that the mixture was more productive and able to maintain stable yields over time. Moreover, the production of the mixture was still the highest in comparison to the pure standing crops also under artificial shade conditions. We observed a detrimental effect of artificial shade on sulla and mixture especially in spring, when the cool season crop is more productive and light resulted to be a limiting factor. On the other hand, despite its low productivity in comparison to the other crops, ryegrass resulted not affected by shade. Considering the quality of the forage, the nutritive value of the mixture resulted averagely well balanced in comparison to sulla and ryegrass as pure stands. Shading affected the forage quality, showing a slight but not relevant increase in all parameters tested; among the different species evaluated the mixture maintained the best performance also under shading conditions. Despite the variable effects on the performance of the mixture components, these outcomes demonstrated the protective effect of legume-grass intercropping against potential negative effects of light availability reduction on quantitative and qualitative aspects of forage production. The warm-season crop tested under the same shading treatments was alfalfa (Medicago sativa L.). Although its productivity was sensibly affected by shade at each level of light reduction following a linear trend (more shade, less yield), cumulative data showed anyway an acceptable yield also under shading conditions, especially under moderate shading. Regarding the quality of the forage, we focused on crude protein, the pivotal parameter for alfalfa, and no effect of shade was observed. Overall, these results suggest that, if we consider only the aspect of light reduction, alfalfa can be introduced in real AFS, thanks to its high nutritive value and high yield, but especially under extensive AFS rather than intensive systems. Regarding the N2-fixation performance of both, sulla and alfalfa, the percentage of N derived from N2-fixation was higher in the shaded plots, while the N yield, which depends mainly on shoot biomass production, showed averagely higher values in not shaded plots. Thus, it is likely legumes in shaded plots might invest less resources in shoot biomass production while spending more energy in accumulating reserves in the roots, and rhizobial activity might benefit from this increased availability of resources. Further studies are needed to better understand the ecophysiological relations between symbiotic N2-fixation and shading in AFS, also considering the microclimate conditions, studying microbiological community, and testing these crops also in real AFS. The second field plot trial was conducted to assess: (i) the ability of trees during the first year after planting to reduce N leaching, (ii) the N-fixation of legume sward and (iii) its capability to transfer N-fixed to the trees. Additionally, we wanted also to test the agronomic performance of sulla and ryegrass when introduced in AFS with 1-year old poplars trees. Results showed a higher productivity of sulla in AF in comparison to ryegrass in AF and all the forages grown without trees, probably because sulla may be even less affected by competition with young trees thanks to BNF and the subsidiary production of N. N2-fixation in sulla resulted affected slightly by the tree presence, showing no clear trends, even if the amount of N fixed and accumulated in its biomass resulted higher in close proximity of the trees than far from them. For this reason, we supposed that in the tree-crop interface, sulla invests more energy in N2-fixation, likely due to the belowground competition for resources and soil N that are less available for sulla roots. When trees are still young, and light availability isn’t a limiting factor, this effect does not imply a significant yield depletion in the legume. In our case, it was possible to observe a N-transfer effect from sulla towards poplars, but this did not increase poplar growth. Even if non-fixing trees were intercropped with legume crops, the belowground competition for nutrient resources might have caused a delayed growth rate of trees. Finally, despite the very young age of poplars, a reduction of nitrate content from the center of the plots to the ditch was observed, especially in the tree-crop sampling area. We may think that in the deepest soil layers the roots of poplars could be a barrier to reduce the N loss already in the first year after planting. We can conclude that under Mediterranean rainfed conditions, the presence of the trees and the use of perennial legumes has demonstrated to be pivotal in supplying ecosystems services supporting acceptable and more stable forage productions from both, quantitative and qualitative points of view. Hence, a transition towards agroecology management of forage-based systems seems reasonably possible and could be crucial to increase productivity and land use efficiency, while mitigating environmental risks and soil degradation

N2 use in perennial swards intercropped with young poplars, clone I-214 (Populus euramericana (Dode) Guinier), in the Mediterranean area under rainfed conditions

Intercropping perennial legumes with trees can reduce Nitrogen (N) losses, due to the high amount of N accumulated in stable forms in the soil and permanent soil cover during the whole year. Although N cycling improvement in mature agroforestry systems (AFS) was well documented, there is a lack of knowledge regarding systems in transition to AF. In this work, we studied the association of two perennial forage crops, namely ryegrass (Lolium multiflorum Lam.) and sulla (Hedysarum coronarium L.), with 1-year old poplars, to evaluate: (i) the agronomic performance of sulla and ryegrass with vs. without intercropped poplar trees; (ii) the N-fixing ability of sulla in association with trees; (iii) the N transfer effect from sulla and growth promoting effect on poplar; and finally (iv) the nitrate leaching reduction due to the presence of poplar trees associated to forage crops. The layout was arranged in a two-factor randomized complete blocks design (RCB) with three replicates. The first factor tested (crop species) implied two different swards, namely sulla and ryegrass. The second factor (cropping system) included two different systems: PAST i.e., a pastoral system without trees, and SIPAST, i.e., a silvo-pastoral system with one poplar tree row beside the sward. Sulla resulted more productive than ryegrass when associated with trees (+35%). No clear trend was observed about the tree influence on N-fixation in sulla, but the amount of N fixed resulted higher in in sulla grown in the SIPAST near the trees (+35%). Poplar plants, even in the first year after planting, resulted effective yet in reducing the nitrate flux from the crops towards ditches. Further investigations are needed to study other swards in young AF and better understand the N dynamics; in particular, it could be worth to assess the nutrient flux in the soil solution

Evaluating rye and squarrose clover cover crops for no-till organic tomato production

The omission of tillage operations i.e., no-till, is part of conservation practices that have gained increasing popularity since the 1970s in conventional agriculture. No-till has been recently tested in organic farming as an agroecological way for soil management in combination with cover crops. The choice of cover crop is key to addressing the chal- lenges arising with this technique, often related to weed and nutrient management. A field plot trial was set up in 2019-2020 at the Centre for Agri-environmental Research “Enrico Avanzi” in Pisa (Italy) to evaluate the effects of three cover crops and their resi- dues management on weed suppression, soil N availability and tomato yield. Rye (Secale cereale L.) and squarrose clover (Trifolium squarrosum L.) pure stands and their mix- ture in half rates, were either turned into the soil or flattened via roller-crimper before tomato transplantation. Weedy plots with no cover crop preceding tomato served as a control. At termination time, rye and the mixture had equally the highest dry residues per unit area. The presence of a living cover crop decreased winter-spring weed abun- dance measured in dry biomass. Rye and the mixture controlled weeds better than squarrose clover. Weed control continued during the season till harvest with a notable performance by the mixture in no-till. Weed community composition seemed also to be influenced by tillage regime and cover crop choice. Tomato plant growth and yield meas- ured in fruits number and fresh weight were affected by the cover crop. Tomato plants following squarrose clover and the mixture produced more than the control, while prob- ably N immobilization from rye residues hindered tomato growth and yield. Our work showed that legume-cereal cover crop mixture such as rye-squarrose clover can be a good choice for no-till to be successful in Mediterranean organic vegetable systems

Simulating the effect of light availability reduction on grass and legume swards in a Mediterranean rainfed plot trial

Agroforestry (AF) is defined as the integrated management of woody species on croplands or grasslands and it is indicated as one of the farming systems with the greatest potential for climate change mitigation and adaptation (Kay et al. 2019). In Italy, agroforestry systems cover an area of 1.4 millions ha mainly based on silvoarable system with high value trees and agro-silvo-pastoral systems (Paris et al., 2019). In Tuscany, a typical silvoarable system consists in silvoarable olive grove intercropped with a low- productive natural pasture, usually not grazed, until the early-summer period when shallow tillage is performed in order to decrease water competition between herbaceous plants and trees (Mantino et al., 2016). Growing legumes, and in particular perennials legumes, under the canopy of tree crops could be a practice to improve sustainability of Mediterranean AF systems mainly by increasing the Nitrogen (N) content in the soil through symbiotic N2 fixation, thus reducing the reliance on mineral N fertilisers (Anglade et al., 2015; Hernandez-Esteban et al., 2019) and enhancing soil cover protection (Vallebona et al., 2016). The most important perennial legume crop in Mediterranean area is alfalfa (Medicago sativa L.). The effect of tree presence on legumes has been evaluated by several studies, reporting negative effects on yield, due to lower water availability (Nasielski et al., 2015), and reduced light availability (Gea- Izquierdo et al., 2009; Moreno et al., 2007), respect to an open field. Despite this, it was reported that the alfalfa nutritive value is not negatively affected by tree presence (Mantino et al., 2016). In Tuscany, the biennial legume Sulla (Hedysarum coronarium L.) could be interesting for its rusticity, productivity, and quality of the forage. Nevertheless, there is still a lack of knowledge on how the reduced light availability affects the development, the biomass accumulation and quality of forage species. Therefore, a rainfed plot trial was designed with the goal of investigating the effect of reduced light availability on Mediterranean legumes and grasses forage species. In October 2019, the plot trial was established at the Centre for Agro-Environmental Research "Enrico Avanzi" of the University of Pisa, San Piero a Grado (Pisa) (43°41'6.97"N 10°20'29.22"E), on a clay-loam soil with 2.5 % w/w of organic matter content in the topsoil (0 - 0.3 m) and 8.1 pH. Before sowing, performed on October 21st, 100 kg ha-1 of P2O5 were broadcast applied as triple superphosphate. The sowing was carried out on October 21th. The experimental layout complies with a two factor completely randomized block with four replicates (18 m2 sizing each plot). One factor includes five levels assigned to five different swards: i) sulla cv. Silvan, (ii) ryegrass (Lolium multiflorum L. cv. Teanna), (iii) mix of sulla cv. Silvan and ryegrass, 50:50 (iv) mix of sulla cv Silvan, sulla cv. Chiara Stella and sulla cv. Avorio 33:33:33 and (v) alfalfa cv. Messe. Second factor has three increasing shading levels: S0) the control representing full light availability, S25) and S50), corresponding to a reduction of potential light availability of 25 and 50% respectively. Shading was provided by woody slats, north-south oriented, 2.0 m long and 0.10 m wide, with a distance between each slats of 0.10 m for S50 and 0.20 m for S25, covering a total surface of 4 m2. Slats were placed at 80 cm above ground level after the sowing (Fig.1). Light availability over and under the swards canopy is monthly measured by means of the SunScan (Delta- T Devices Ltd, Cambridge, UK) multiprobe sensor. Preliminary data showed no significant effect of shading treatments on seedling emergence for all the evaluated swards. Data about yield and nutritive value of herbage biomass, below-ground biomass and N2 fixation will be evaluated for the next two years. This study received funding from the Tuscany Region Rural Development Plan, PINDARICO project - Measure 16.2 - 2017

An experimental dataset on yields of pulses across Europe

Abstract Future European agriculture should achieve high productivity while limiting its impact on the environment. Legume-supported crop rotations could contribute to these goals, as they request less nitrogen (N) fertilizer inputs, show high resource use efficiency and support biodiversity. However, legumes grown for their grain (pulses) are not widely cultivated in Europe. To further expand their cultivation, it remains crucial to better understand how different cropping and environmental features affect pulses production in Europe. To address this gap, we collected the grain yields of the most cultivated legumes across European countries, from both published scientific papers and unpublished experiments of the European projects LegValue and Legato. Data were integrated into an open-source, easily updatable dataset, including 5229 yield observations for five major pulses: chickpea (Cicer arietinum L.), faba bean (Vicia faba L.), field pea (Pisum sativum L.), lentil (Lens culinaris Medik.), and soybean (Glycine max (L.) Merr.). These data were collected in 177 field experiments across 21 countries, from 37° N (southern Italy) to 63° N (Finland) of latitude, and from ca. 8° W (western Spain) to 47° E (Turkey), between 1980 and 2020. Our dataset can be used to quantify the effects of the soil, climate, and agronomic factors affecting pulses yields in Europe and could contribute to identifying the most suitable cropping areas in Europe to grow pulses