Kvävefixering och kvävecirkulering i sort- och artblandningar av åkerböna och vårvete i ett ekologiskt odlingssystem

This study was undertaken to evaluate the effect of varietal and species diversity of faba bean and spring wheat on N2 fixation and N cycling in an organic system. The field experiment was carried out at SLU Alnarp to quantify biological N2 fixation using 15N natural abundance method. The measurements were taken at two physiological stages of faba bean, at pod filling and at full maturity. In general N2 fixation, shoot N yield and soil N uptake increased at maturity while the proportion of N derived from fixation, %Ndfa and biomass yield decreased. No significant effect of diversity was found on N2 fixation but significant effect of diversity on %Ndfa was recorded at full maturity. Significantly positive correlation was found between the amount of N2 fixed and biomass yield, %Ndfa and N concentration. Soil N uptake positively correlated with shoot N yield but negatively with N2 fixation. The calculated biomass yield and N2 fixation per sown faba bean plant showed the increased advantage of varietal mixture and intercropping. The advantages also occurred in residual Nitrogen, Crop Harvest Index, Nitrogen Harvest Index, Nitrogen Balance and Nitrogen Utilization Efficiency. Significantly higher Nitrogen Utilization Efficiency was found in mixture of Alexia, Gloria and Wheat. Highest N balance was found in mixture of Alexia and Gloria. Crop Harvest Index was highest in mixture of faba bean varieties with spring wheat but the growth and development of wheat was highly suppressed in the mixture. The potential application of the study outcomes in practical farming situations was estimated by a questionnaire study with structural and semi structural questions. The questionnaire was sent to advisors working within the organization “Greppa Näringen” (Focus on Nutrients) program to increase farmers‟ awareness about agricultures‟ potential impact on climate change. The interest among responding advisors (13 out of 35 who received the questionnaire) on crop diversification was high. The diversity in cropping system including faba bean was perceived important by a majority of the advisors mainly for developing crop rotation that decrease the need to buy animal feed and industrial N. Marketing, harvesting and susceptibility to drought were the main concerns associated with diversification of faba bean crops. Based on the results from the empirical study and questionnaires I can conclude that diversification of cropping systems is a very important strategy from both environmental and agronomic aspects

Competitive forbs in high-producing temporary grasslands with perennial ryegrass and red clover can increase plant diversity and herbage yield

In highly productive temporary grasslands in Europe, plant diversity is usually low. Some non-leguminous species have shown a high competitive ability in temporary grasslands and can increase plant diversity without compromising yields. In an experiment, the competitiveness and productivity of three forb species: chicory (Cichorium intybus), ribwort plantain (Plantago lanceolata) and caraway (Carum carvi), grown in different proportions in mixtures including traditional sown grassland species, perennial ryegrass and red clover, were examined with slurry application as an additional factor. Dry matter (DM) yield and botanical composition were measured during one complete growing season. Annual DM yields were mostly similar when forbs were included in the grassland mixture. A three-species mixture (perennial ryegrass, red clover and ribwort plantain) had the highest yield potential, especially for the slurry application treatment. Chicory and ribwort plantain were highly competitive in the mixtures. The response in the DM yield of perennial ryegrass to slurry application was considerable, but no consistent trend was found in the forbs. In conclusion, forbs contributed to increased plant species diversity and herbage DM yield, and fertilisation had positive effect on herbage yield of grassland mixtures

Diversifying European agricultural systems by intercropping grain legumes and cereals

Cropping system diversification is a key factor in developing more sustainable cropping and food systems. The agroecological practice of intercropping, meaning the simultaneous cultivation of two or more species in the same field, has recently gained renewed interest as a means of ecological intensification in European agricultural research. We discuss some recent research developments regarding 1) intercropping for ecological intensification in agroecological and conventional cropping systems, 2) studies on nitrogen resource use by cereal-grain legume intercropping cultivation, 3) the role of intercropping in the management of biotic stressors, especially weeds, and 4) intercropping as a means of creating cropping systems that are more resilient to the abiotic and biotic stress associated with climate change. Finally, we propose methods for the greater adoption of intercropping in European agriculture by unlocking farming systems from upstream and downstream barriers, with the aim of developing more sustainable agricultural and food systems

Exploring the inner workings of design-support experiments: Lessons from 11 multi-actor experimental networks for intercrop design

New forms of field experimentation are currently emerging to support transitions towards sustainable agriculture, including “multi-actor experimental networks” (MAENs). Both in public policy and in academic research, such networks are increasingly presented as a promising approach for fostering sustainable farming system design. Many studies have inventoried, categorized and compared experimental processes to discuss them in relation to contemporary issues. However, to our knowledge, these studies have not considered how MAENs can be implemented, nor their various contributions to sustainable farming systems design. The present work therefore explores the mechanisms whereby MAENs, depending on the way they are managed, support participatory design processes. Drawing on concepts from the design sciences, we studied 11 MAENs established across Europe to support intercrop (IC) design for field crops. Data on the characteristics of these 11 MAENs and their contributions to IC design were collected through individual and group interviews with the network pilots, and the study of individual MAEN documents. The analysis provides three types of results. First, we identify nine generative functions, that is, various processes through which experiments contribute to IC design, including: (i) finding one best option or highlighting contrasts between different ICs; (ii) highlighting the conditions that must be met for an IC to achieve certain effects; (iii) discovering new ICs or properties of ICs; and (iv) supporting the emergence/continuation of collective action for IC design. Second, we highlight different ways to manage MAENs, in other words ways to manage several experiments (in space and time) with a view to supporting participatory IC design. We show that this involves (i) coordinating several objects under design within a network of experiments, (ii) managing the coexistence of experiments guided by different logics in the same geographical area, and (iii) developing interactions between the experiments at a given point in time and over time to support IC design. Third, based on the previous results, we show consistency between the various contributions of MAENs to IC design and the different ways in which the pilots managed them, and we highlight three strategies for managing MAENs to support IC design: MAENs supporting (i) R&D-led design; (ii) farmer-led; and (iii) distributed design. All these results provide mechanisms, points of reference, MAEN types and characteristics to inspire and foster the reflexivity of R&D actors interested in developing such participatory networks in the future

Exploring the inner workings of design-support experiments: Lessons from 11 multi-actor experimental networks for intercrop design

New forms of field experimentation are currently emerging to support transitions towards sustainable agriculture, including “multi-actor experimental networks” (MAENs). Both in public policy and in academic research, such networks are increasingly presented as a promising approach for fostering sustainable farming system design. Many studies have inventoried, categorized and compared experimental processes to discuss them in relation to contemporary issues. However, to our knowledge, these studies have not considered how MAENs can be implemented, nor their various contributions to sustainable farming systems design. The present work therefore explores the mechanisms whereby MAENs, depending on the way they are managed, support participatory design processes. Drawing on concepts from the design sciences, we studied 11 MAENs established across Europe to support intercrop (IC) design for field crops. Data on the characteristics of these 11 MAENs and their contributions to IC design were collected through individual and group interviews with the network pilots, and the study of individual MAEN documents. The analysis provides three types of results. First, we identify nine generative functions, that is, various processes through which experiments contribute to IC design, including: (i) finding one best option or highlighting contrasts between different ICs; (ii) highlighting the conditions that must be met for an IC to achieve certain effects; (iii) discovering new ICs or properties of ICs; and (iv) supporting the emergence/continuation of collective action for IC design. Second, we highlight different ways to manage MAENs, in other words ways to manage several experiments (in space and time) with a view to supporting participatory IC design. We show that this involves (i) coordinating several objects under design within a network of experiments, (ii) managing the coexistence of experiments guided by different logics in the same geographical area, and (iii) developing interactions between the experiments at a given point in time and over time to support IC design. Third, based on the previous results, we show consistency between the various contributions of MAENs to IC design and the different ways in which the pilots managed them, and we highlight three strategies for managing MAENs to support IC design: MAENs supporting (i) R&D-led design; (ii) farmer-led; and (iii) distributed design. All these results provide mechanisms, points of reference, MAEN types and characteristics to inspire and foster the reflexivity of R&D actors interested in developing such participatory networks in the future