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There is an increasing need for more sustainable and diversified cropping systems while guaranteeing adequate crop yields and economic viability for European farms. The intercropping of lentils with wheat can be a valuable agroecological practice for stabilizing crop yields and improving weed control; however, this requires better knowledge about the technical viability, suitable varieties, sowing density, management practices for different conditions, and the feasibility of these solutions for farmers. In this paper, we present a three-stage participatory approach aimed at involving farmers in the evaluation and design of knowledgeintensive agroecological cropping systems and apply it to the case of wheat-lentil intercropping. The proposed approach is articulated into three connected stages involving experiments at different scales (plot, field, and farm) and with different grades of interactions among farmers and researchers regarding the design of experiments and the evaluation of the results. In the first stage, we set up controlled plot experiments at an experimental station allowing all interested farmers to observe and comment on the various treatments that were investigated during dedicated events. This stage tested the potential of intercropping to improve the sustainability of the local farming system and provide a solid scientific background to the ecosystem services provided by wheatlentil intercropping, such as crop production, yield stability, and weed control. While being agronomically beneficial, the technical feasibility and economic benefits of wheat-lentil intercropping have yet to be proven. Therefore, based on the results obtained from the first stage and the feedback of local farmers on the opportunities and weaknesses of the on-station application of wheatlentil intercropping, a second experiment was carried out using commercial agriculture machines to test the technical viability of intercropping at a larger scale. In the final third stage, we set up a co-designed on-farm experiment aimed at supporting a farmer in establishing lentil-wheat intercropping adapted to the farm conditions. This approach demonstrated that gradually involving farmers in the experimental process, starting from evaluating the most promising agroecological solutions on station to implementing them on farms, supports a successful agroecological transition of farms towards more diversified cropping systems. [ABSTRACT FROM AUTHOR]

Cultivar mixtures are a useful tool to enhance cultivated biodiversity to buffer crop biotic and abiotic stresses. There are multiple pieces of evidence of mixture advantages in terms of pathogen control and increase in yield amount, stability and quality. Lentil represents a founder crop in the Mediterranean, yet it experiences strong yield fluctuations in the face of abiotic stresses. The present study aims to assess the mixing ability of four Italian commercial lentil lines in terms of yield amount and stability, nodule number, total lentil biomass and sensitivity to weeds. Since there is very limited information on lentil genotype traits, two-, three- and four-cultivar mixtures were designed with a trait-blind approach and compared to sole cultivars. The nodule number was mainly influenced by cultivar and weather; no interaction between cultivars was observed. Treatments were differently sensitive to weeds, but the effect of spatial heterogeneity prevailed over that of the cultivar. The average yield stability of all mixtures was significantly higher than pure stands, but in terms of yield amount, individual mixtures either outperformed or were outperformed by pure stands. Against our expectations, cultivar mixtures showed the most advantages in the most productive year: likely, the reason lies in the supposed low genetic diversity of commercial lentil lines in Italy. We encourage further research, taking into account the diversity of Italian lentil landraces, in order to gain a broader genetic base for the implementation of a trait-based approach, which may lead to better-performing mixtures. [ABSTRACT FROM AUTHOR]

Band steaming is a non‐chemical weed control method of increasing interest for highly remunerative, low competitive crops. This study aimed to test the field application of a new prototype of band‐steaming machine in three organic fields under contrasting Mediterranean environmental conditions. Trials were conducted in carrot under real‐field conditions to investigate the effects of three steaming doses and one control (no steaming) on weed vegetation and crop yield. Soil temperature at steaming application, weed density at species level during carrot crop growth, and weed and carrot biomass at harvest were sampled at each site. Band steaming significantly affected total weed density: when comparing the untreated control with the highest steam dose, weed density reduction ranged from 62% (−492 plants m−2) at site II to 94% (−146 plants m−2) at site III. Generally, diversity of weed communities decreased with increasing steaming dose, indicating a progressive species filtering effect: Fumaria officinalis L. and Sonchus oleraceus L. were filtered by steaming application at site I, while Polygonum lapathifolium L. and Portulaca oleracea L. were filtered at sites II and III. Weed community composition was affected by steaming dose at two sites out of three. Small seeded species (seed mass <1.5 mg) were less tolerant of steaming than species with large seeds. Through reduction in weed density, steam application gave carrot a competitive advantage, increasing fresh yield from 47% at site III (+3,646 g m‐2) to 92% at site II (+1,866 g m‐2), compared with yields at non‐steamed plots. [ABSTRACT FROM AUTHOR]

Green manure and compost-enriched in phosphorus can promote the sustainability of cropping systems by increasing soil fertility over the long term. They can also be used to manage crop/weed interactions, a key element in guaranteeing an appropriate level of satisfactory crop yields. We studied how green manuring with hairy vetch (Vicia villosa Roth.) and the application of different types of phosphorous-enriched compost affect weed/maize (Zea mays L.) interactions in an organic stockless Mediterranean agroecosystem for two consecutive dry years. Green manure stimulated the expression of maize traits related to a higher competitive ability against weeds, such as early growth, height and leaf area index, while the effect of compost was less clear. Regarding crop/weed competition, both green manuring and a phosphorus-enriched compost application gave a significant advantage to maize. Neither green manure nor compost increased total weed density and biomass compared to the control. Green manuring significantly affected the weed community composition. The relative density of ruderal and competitive-ruderal species (according to Grime's classification) was higher in plots where the green manure was applied. The use of green manure, together with novel composting techniques, significantly affected crop/weed competitive interactions, favoring maize, but also creating favorable conditions for unwanted weed species such as competitive-ruderals. Increasing nitrogen availability in the early growth stages of maize through green manuring can increase crop competitive ability. However, this may not suffice to preserve the system from future weed problems, should potentially detrimental species be selected. Dedicated strategies for the control of emerging weed species may thus be needed. [ABSTRACT FROM AUTHOR]

Relay intercropping is considered a valuable agroecological practice to increase and stabilize crop yields while ensuring the provision of several ecosystem services as well as sustainability and resilience to changing climatic conditions. However, farmers are still reluctant in the use of intercropping practices since there is a huge knowledge gap regarding the time of sowing, sowing ratio, crop stand density, and cultivar choice. In this study, we carried out a 3-year field experiment in Central Italy to assess the effect of relay intercropping on the agronomic performance and competitiveness of winter durum wheat (Triticum durum Desf. cv. Minosse) and spring lentil (Lens culinaris Medik. cv. Elsa) under a low-input management system, comparing different crop stand types (monocrop vs. intercrop) and target plant densities (350 plants m2—full dose vs. 116 plants m2—1/3 dose). The results revealed that intercropping increased grain yield compared to monocropping: significantly (p < 0.0001) against both monocrops in 2021 and non-significantly against durum wheat in 2019 and 2020. Yield advantage in both intercropping systems ranged between 164 and 648%. Durum wheat competitiveness was stronger in 2019 and 2021, while lentil was the most competitive component in 2020. Intercropping favored P accumulation in durum wheat shoots. There was no difference in grain yield of both crops between the highly- and lowly-dense system in 2020 and 2021. Both intercropping strategies were as effective as mechanical hoeing in controlling weeds and proved beneficial in stabilizing lentil productivity. Further economic analysis capturing the additional costs incurred in intercropping and mechanical weeding would highlight the magnitude of profitability of these systems. [ABSTRACT FROM AUTHOR]

Vineyards are among the land uses with the highest soil degradation rate in Mediterranean Europe, mainly due to intensive tillage management. Therefore, practices able to foster soil health are critical to promote sustainable wine production. We studied the following treatments in two organic farms in Chianti Classico (Italy): conventional tillage, spontaneous vegetation, pigeon bean (Vicia faba var. minor) incorporated in spring and a mixture of barley (Hordeum vulgare) and squarrosum clover (Trifolium squarrosum), both incorporated and left as mulch. An innovative approach, based on gamma-ray and apparent electrical conductivity, was used to account for the fine-scale soil variability that was included in the statistical model. Mulched groundcovers were associated with higher soil organic matter compared to tillage, already after two years. An increased N availability was found under all groundcovers compared with tillage. The effect of soil management practices on P2O5 strongly varied across farms and years, while it was not statistically significant on K availability. Spontaneous vegetation positively influenced the soil structure index, soil penetration resistance and soil biological health. The results show that mulched groundcovers can improve soil health already in the short term, thereby potentially increasing the sustainability of the wine sector. [ABSTRACT FROM AUTHOR]

Weed control in organic conservative vegetable systems is extremely challenging and the use of legume permanent living mulches (pLM) presents an interesting opportunity. The successful use of pLM is largely determined by the choice of appropriate legumes which are able to combine adequate weed control with a marginal competitive effect on the cash crop(s). However, the availability of legumes for such systems is limited and their characterization based on growth traits can support the selection of suitable legumes for conservation organic vegetable systems. The current study investigated weed control capacity and variability in morphological and phenological traits relevant in inter-plant competition among a range of 11 commercial cultivars of legumes and seven ecotypes of Medicago polymorpha (bur medic). For commercial cultivars, Lotus corniculatus (bird's-foot trefoil) and Trifolium repens (white clover) showed the best weed control capacity, while Trifolium subterraneum (subterranean clover) and Medicago polymopha had more suitable characteristics for a rapid and complete establishment of the pLM. Overall, legume mulches appear more effective in dicotyledonous than in monocotyledonous weed control. Trifolium subterraneum cv. Antas and T. repens cv. Haifa were identified as the potentially most suitable legumes for use as pLM and their use in mixtures could be a promising solution. In addition, the ecotypes of Medicago polymorpha Manciano and Talamone proved to be well adapted for local environmental conditions and they showed a better weed suppression than the commercial cultivars of Medicago polymorpha. [ABSTRACT FROM AUTHOR]

The study of weed germination can improve knowledge on their seasonal dynamics in fields and facilitate the design of ecologically sustainable management. An experiment was conducted to evaluate the effect of a range of constant and alternate temperatures on the germination of Chloris barbata, Cynodon dactylon, and Cyperus rotundus collected in Angola. Interesting differences were observed between the germination responses of the three species. No germination was observed for any species at 10 or 15–5 °C. Chloris barbata quickly germinated at most constant and alternate incubation temperatures, showing low primary dormancy and high germinability. Fast and high germination was observed for Cynodon dactylon at most alternate temperatures, while lower germination percentages were achieved at constant temperatures, especially the highest ones. Cyperus rotundus achieved good germination percentage at alternate temperatures, even if with slower and more extended germination dynamics than the other species, while almost no seeds germinated at constant temperatures. This study improves our knowledge of germination ecology for these species and allows some control tools to be identified, such as soil tillage, cover crops, and living or dead mulches, which can contribute to their ecologically sustainable management. [ABSTRACT FROM AUTHOR]

Relay intercropping of service legumes (living mulch) is a valuable agroecological practice to support nutrient availability, yield and non-chemical weed control in a crops sequence, if suitable legumes are chosen. This study tested the suitability of eight legume living mulches for relay intercropping in durum wheat (Triticum durum Desf.) evaluating their effects on the subsequent forage sorghum (Sorghum bicolor L. Moench) in a Mediterranean low-input cereal-based cropping system. Legumes include perennial (Medicago sativa , Medicago lupulina , Trifolium repens , Hedysarum coronarium), annual (Trifolium incarnatum , Trifolium resupinatum) and annual self-seeding (Trifolium subterraneum , Medicago polymorpha) species. A plot experiment repeating two times a wheat-sorghum crop sequence, was carried out in Central Italy to assess the effects of relay intercropping of legumes on agronomical and economic performance of the associated wheat and subsequent sorghum. The legumes were undersown in the already developed durum wheat in late winter. They were maintained after wheat harvest and used as green manure by biomass chopping and plowing in the following spring at sorghum sowing time. None of the intercropped legumes affected N uptake or grain protein content of the companion wheat with respect to the control (wheat sole crop). In the spring before sorghum sowing, N input from legume biomass residues was assessed and it sensibly changed according to legume species, ranging from 1.2 (T. incarnatum) to 182 kg ha−1 (H. coronarium). The legume treatments significantly affected the N uptake in the subsequent sorghum and it ranged from 20.2 to 172.6 kg ha−1. Without the use of additional external nitrogen input, average sorghum dry biomass production preceded by H. coronarium (13.3 t ha−1), T. repens (11.8 t ha−1), T. subterraneum (11.0 t ha−1) and M. sativa (9.3 t ha−1) was in line with the productive level under conventional conditions. Biomass residues of M. sativa significantly reduced the total weed biomass in sorghum by 65% compared with the control. In sorghum, preceding legumes such as T. resupinatum and T. incarnatum promoted dicotyledonous weed growth. Hedysarum coronarium and T. repens were the best legumes for relay intercropping in the low-input wheat-sorghum crop sequence under Mediterranean conditions of this study according to agronomic and economic evaluation. These legumes were able to increase soil nitrogen content allowing to significantly reduce external nitrogen fertilization while optimizing sorghum production. When gross income is calculated at cropping system level, most legumes provide a positive economic balance. • Legume living mulches do not affect nitrogen (N) uptake of the co-cultivated wheat. • Suitable legumes can provide up to 182 kg N ha−1 in a wheat-sorghum crops sequence. • Suitable legume mulches support the sorghum yield without the need for fertilizers. • Living mulches maximized overall economic income in a wheat-sorghum crop sequence. • Hedysarum coronarium and T. repens provided the best agro-economic performance. [ABSTRACT FROM AUTHOR]

Little is known about the long-term contribution of cover crops to weed management in tillage- and herbicide-based systems. Do cover crops mainly filter weed species capable of setting seeds during the fallow period? Can cover crop biomass productivity explain differences in weed suppression among cover crop species? Does reduced weed seedbank density translate into lower weed biomass and higher crop productivity? Soil samples (0–15 cm) were collected in 2018 after cover crop termination and used in a greenhouse seedling emergence assay to assess the topsoil weed seedbank capable of germinating 25 years after the beginning of a split-plot experiment on tillage systems (conventional vs. reduced) and cover crops (bare soil control, Brassica juncea (brown mustard), and Vicia villosa (hairy vetch)). Total density and density of the 10 most abundant weed species in the topsoil seedbank were related to observations of weed species visual soil cover, total weed biomass, cover crop biomass, and cash crop grain yield made during the six years which preceded the weed seedbank assessment. Weed seedling density was also used to compute community weighted mean of germination and flowering period. In comparison with the bare soil control, hairy vetch suppressed total weed seedling density by 40%, whereas brown mustard showed no effect. In comparison with the bare soil control, hairy vetch suppressed weed seedling density of Cerastium glomeratum (−87%), Veronica persica (−86%), Capsella bursa-pastoris (−57%) and Poa annua (−42%), whereas brown mustard only suppressed C. bursa-pastoris (−65%) and V. persica (−49%). The suppressive effect of hairy vetch on these four species translated into a significant reduction of community weighted mean of autumn/winter germination period and March to July flowering period. The contrasted suppressive effect of brown mustard and hairy vetch on weed seedling density of these four species was related to contrasted competitive interactions during the four previous cover crop seasons. However, differences in weed suppression between hairy vetch and brown mustard could not be fully explained by differences in biomass productivity. Management intensity (e.g. herbicides and tillage) potentially smoothed out differences in weed suppression between cover crop treatments because no effect of cover crops were observed on total weed biomass or gain yield of the subsequent crops over the 2012–2017 period. Cover crops contribute little to weed management in herbicide and tillage-based cropping systems. The weed suppressive effect of cover crops should be further explored in cropping systems which minimise herbicide use and tillage intensity. • The contribution of cover crops to weed management in tillage-based systems is unclear. • Cover crops can reduce seed set of short-cycled weeds during the winter fallow. • Cover crop biomass could not fully explain the level of weed suppression. • Management intensity homogenized initial differences among cover crop treatments. [ABSTRACT FROM AUTHOR]