Is agroecology the most sustainable approach for all organic farming systems?

Analysis of very diverse Italian organic production systems through dedicated research projects revealed that all of them have ample margins of improvement in sustainability. The ‘multifunctional organic system’ (small-scale farms, produce sold on local or regional markets, agroecologically-based management) must seek optimisation of production, cost reduction, and a better access/distribution of labour in peak times. The ‘specialised organic system’ (medium-large farms, produce sold on supermarkets or abroad, input substitution-based management) should seek viable, more ecologically-based alternatives to input substitution to mitigate its high environmental impact. Literature suggests that this divergence between organic production systems is occurring in many countries. National and international organic standards should not only be more aligned towards their claimed sustainability objectives but also clearly distinguish from future integrated production standards. Incorporation of more agroecologically-based management options (e.g. functional biodiversity) should help keep organic farming duly identifiable by people, but practical solutions would need to be tailored to the specific production system

A FUNCTIONAL AGROBIODIVERSITY APPROACH TO IMPROVE ORGANIC WHEAT PRODUCTION

Crop agrobiodiversity is an asset to improve organic and low-input wheat production, but a clear framework is necessary to translate scientific evidences into practice. Here we present results from a field experiment on common wheat, focusing of cultivar identity, genetic heterogeneity and on the inclusion of a legume living mulch. This experiment provided us insights on how to improve yield, yield stability and weed reduction through adequate cultivar choice and diversification of the crop stand

SIMBIO-VEG: an interdisciplinary project for improvement of organic systems and meth-ods in arable and vegetable cropping

SIMBIO-VEG is the first large interdisciplinary research project on organic farming ever being funded in Italy. The project partnership is composed of eight Working Units including Universities as well as public and private research centres and associa-tions, with a high degree of interaction among them. SIMBIO-VEG aims to acquire knowledge on the func-tioning of organic arable and vegetable cropping systems, as to (1) optimise systems management and the cultural practices (methods) therein, and improve the understanding of how organic systems and meth-ods influence produce quality and environmental impact. SIMBIO-VEG activities are structured in four strongly integrated research lines. Line 1 aims to understand the functioning of organically-managed agroecosystems and evaluate the technical and agro-nomic feasibility of crop production methods applied therein. Line 2 aims to evaluate the effects of organic systems and methods on overall produce quality, including both standard and innovative methods. Line 3 aims to evaluate the sustainability of organic sys-tems and methods through assessment of parameters and indicators related to soil quality, environmental impact, and economic viability. Lastly, line 4 is aimed to favour diffusion of results and innovation transfer through a comprehensive set of activities

Mixtures of Commercial Lentil Cultivars Show Inconsistent Results on Agronomic Parameters but Positive Effects on Yield Stability

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

Targeted timing of hairy vetch cover crop termination with roller crimper can eliminate glyphosate requirements in no-till sunflower

No-till cropping systems with cover crops can improve soil health, but often rely on glyphosate, which is a contentious herbicide. In this study, we investigated whether a system based on the direct sowing of sunflower (Helianthus annuus) in the dead mulch of a roller-crimped hairy vetch (Vicia villosa) could be competitive with a system where glyphosate is also sprayed to terminate the cover crop and to control weeds. We hypothesized that optimum timing of roller-crimping would be key to eliminate glyphosate requirements while maintaining sunflower performance. In a 3-year on-farm experiment, we compared three vetch termination stages (early: pre-flowering; Intermediate: beginning of flowering; late: 70% flowering) and three glyphosate rates (Nil, half and full, i.e. 1440 g of active ingredient per hectare). Vetch biomass increased progressively from early to late termination stages, and ranged between 414 and 658 g m−2. Higher vetch biomass was correlated with lower weed biomass. Treatments had inconsistent effects on weed diversity and composition, largely determined by the interactions between treatments and seasonal (different years) or local factors (different fields). Glyphosate-based treatments seemed to select for aggressive weed species, but no clear species filtering effect based on ecological or functional traits was detected. Shannon H’ was positively correlated with sunflower grain yield below a weed dry biomass threshold of 150 g m−2. Crop yield with early termination stage was a failure without glyphosate application. However, crop yield with late vetch termination was acceptable, being at par or 15% higher (mean of first and second years) in no-glyphosate compared with glyphosate-based treatments. Crop gross margins showed the same trend (+33% for no-glyphosate compared with glyphosate-based treatments). This study, for the first time, shows that targeted timing of roller-crimped hairy vetch in no-till sunflower can result in equal agronomic and economic performances as addition of glyphosate

Designing cover crop mixtures to enhance potential weed suppression in organic no-till vegetable systems.

Introduction No-tillage in vegetable systems can provide several benefits, but it can only be implemented if there is a powerful strategy to control weeds (Morse, 1999). Cover crops are an essential part of an integrated weed management strategy in no-till organic and low input vegetable systems (Altieri et al., 2011). However, few studies focus on no-tillage practices in organic vegetable systems in European environments, particularly in Mediterranean contexts (Isik et al., 2009). Cover crop effectiveness in weed control, depend on crop traits linked with weed suppressive ability. Mixtures have been used to improve effectiveness of cover crops (Wortman et al., 2012; Smith et al., 2014, Finney et al., 2016). Nonetheless, to our knowledge, this is the first study adopting a functional approach to the design of cover crop mixtures. Our objective was to investigate the effect of functional diversity and composition of cover crops in controlling weeds before transplanting aubergine (Solanum melongena L.), highlighting the relationship between functional traits and weed suppression. Materials and Methods A field trial was performed in an organic field located at CIRAA, University of Pisa, Italy, using a randomized complete block design with 3 replicates and 18 treatments. We selected 8 cover crop species clustered into 4 functional groups as follows: i) large seeded legumes (Pisum sativum L., Vicia sativa L.) characterized by a major development in height; ii) small seeded legumes (Trifolium incarnatum L., T. squarrosum L.) that tend to rapidly cover the soil; iii) grasses (Hordeum vulgare L., Avena sativa L.) characterized by a strong competitive ability and iv) crucifers (Raphanus sativus L., Brassica nigra L.) with allelopathic potential. We designed the mixtures to create a gradient of functional diversity. We included 8 monocrop treatments, 4 two-species mixtures; 4 four-species mixtures including co-presence of 2, 3 and 4 functional groups; an eight-species mixture characterized by the highest level of species and functional diversity, and a no cover crop control. Cover crop plots (3 × 12 m) were broadcast on 27th October 2014 and devitalized on 6th May 2015 with a roller crimper followed by flame weeding. Throughout the experiment, density and height of component cover crop species was regularly recorded. Organically certified aubergine plants (cv “Dalia F1”) were transplanted 5 days after cover crop devitalization. Before devitalization, three above-ground biomass samples of 0.5 m2 per plot were collected. We separated cover crop from weed biomass, and cover crop biomass in the mixtures was further partitioned into component species. Results and Discussion We found no strong correlation between cover crop height and biomass at the time of devitalization. Instead, we found a significant negative relationship between cover crop biomass and weed biomass. This relationship was significantly influenced by treatments. The highest weed biomass was recorded for vetch, although it was significantly lower than in the control. The effect of cover crop biomass on weeds was significant for the small seeded legumes and for pea within the large seeded legumes functional group. We found no significant effect for vetch, as its development was particularly low due to poor establishment in 2014. As for grasses, the effect of cover crop biomass over weeds was not significant. In this functional group, alternative mechanisms, such as allelopathy, might have overcome the biomass effect on weeds. A clear functional differentiation between cover crop species emerges. Conclusions Cover crop mixtures showed a strong potential for weed infestation reduction, given the high amount of biomass produced (Teasdale & Abdul-Baki, 1998). As pointed out by previous research (Mirsky et al., 2013; Mohler & Teasdale 1993), a high quantity of cover crop biomass will ensure good weed suppression during subsequent cash crop cultivation. However, choice and combination of different cover crop functional groups can provide a stronger effect on weeds suppression, through mechanisms not necessarily related to higher biomass production. Our results show that functional characterization of cover crop species and the use of mixtures can be powerful tools in an integrated weed management strategy in organic or low input no-till vegetable systems

Grain yield and competitive ability against weeds in modern and heritage common wheat cultivars are differently influenced by sowing density

Sowing density can have a strong impact on crop stand development during wheat growing cycle. In organic and low-input agriculture, and therefore with minimum or nil use of chemical herbicides, increased sowing density is expected to affect not only grain yield but also weed suppression. In this study we tested, under Mediterranean conditions, six common wheat cultivars (three modern and three heritage) and two three-component mixtures (arranged by combining the three modern or the three heritage cultivars). The different crop stands were tested at sowing densities of 250 (low) and 400 (high, similar to standard sowing density used by local farmers) viable seeds m-2 for two growing seasons. We did not detect a significant effect of crop stand diversity (single cultivars vs mixtures) on grain yield and weed suppression. Differences were ascribed to type of cultivars used (heritage vs modern). Compared to high sowing density, in modern cultivars grain yield did not decrease significantly with low sowing density whereas in heritage cultivars it increased by 15.6%, possibly also because of 21.5% lower plant lodging. Weed biomass increased with low sowing density both in heritage and modern cultivar crop stand types. However, heritage crop stands had, on average, a lower weed biomass (56%) than modern crop stands. Moreover, weed biomass in heritage crop stands at low density (6.82 ± 1.50 g m-2) was lower than that of modern cultivars at the same sowing density (15.54 ± 3.35 g m-2), confirming the higher suppressive potential of the former. We can conclude that lower sowing density can be advisable when using heritage crop stands as it keeps productivity while decreasing plant lodging and maintaining weeds under control

Soil arthropod diversity in organic, integrated and conventional olive orchards in Crete

Soil fauna biodiversity and its functional counterpart were monitored in 24 olive orchards under conventional, organic and integrated management located in eight different locations for a year in Messara valley, in southern Crete. In each location three neighbouring orchards under different management were monitored. Pitfall traps were used as trapping method and fixed data collection points were used in each olive orchard for arthropod fauna monitoring. Counter groups of functional taxa were defined, with respect to services of biological pest control and of nutrient cycling in the olive agroecosystem, Monitoring took place weekly for 5 weeks per season, all year around. Comparison of the different management systems in terms of abundance and diversity of soil arthropods and functional groups was performed. Formicidae, Coleopteran family of Tenebrionidae, Araneae, Colembola and Opiliones were the most abundant taxa found in the olive orchards. A trend of higher total abundance and richness was found in the organic olive orchards, however not statistically significant. Functional arthropod abundance followed a similar trend. Diversity indices did not show a constant pattern in terms of management system comparison; however a trend of higher diversity appeared in the less-intensified organic orchards

Exploiting Plant Functional Diversity in Durum Wheat???Lentil Relay Intercropping to Stabilize Crop Yields under Contrasting Climatic Conditions

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

Changes in Knowledge Management Strategies Can Support Emerging Innovative Actors in Organic Agriculture: The Case of Participatory Plant Breeding in Europe

The “transfer of technology”, typical of a top-down linear process of innovation cannot be used in the new contexts of sustainability, characterised by uncertainty and complexity. There is a need to redefine categories and concepts around which innovation and agricultural policies are built, as those currently in use provide only a partial representation of reality. Innovation paradigms underpinning technological development and public policies design will have a direct impact on decisions regarding which agricultural models will ultimately be supported. Looking at local learning capacity and systems of relations can help to understand the potential to develop innovation within a specific context. This work contributes to the definition of new actors who are developing innovation for sustainability in rural areas. The study focuses on the knowledge systems of farmers who are applying alternative breeding strategies: it uses a network approach to explore the knowledge system in which individual farmers are embedded in order to understand their specific relational features. Three main conclusions emerge from the study: for enhancing the agro-ecological innovation paradigm there is a need to define the ‘innovation broker’, to revise the evaluation system of public research and to integrate innovation and agricultural policies