Inclusion of short-term leys in rotations has been shown to reduce soil organic matter losses and increase yields at lower nitrogen (N) inputs. However, it remains unclear how grass-only or grass-legume leys, in the absence of manure, affect topsoil potential N mineralisation rate, the abundance of alkyl carbon (C) as an estimate of stable C, bulk density, and C stocks under different N fertilisation regimes. This study used a long-term agricultural field experiment series at three sites in southern and central Sweden comprising three crop rotations and four levels of mineral N fertiliser. Potential N mineralisation rates were significantly higher in soils from the ley rotations than from the no-ley rotation across sites. At Stenstugu, characterised by lower initial soil C and coarser texture, N mineralisation was further enhanced in the grass-legume ley rotation compared to the grass ley rotation. Mineral N fertilisation increased potential N mineralisation relative to no N addition. Across all sites, ley rotations, particularly the grass-legume ley, showed a higher abundance of stable C, as indicated by alkyl-C, whereas mineral N fertilisation mainly increased stable C in the pure grass ley and no-ley rotations. Bulk density was lower with N fertilisation than without, and at Stenstugu also in the ley rotations. Topsoil C stocks were higher in ley rotations and under high N fertilisation. Overall, these results indicate that short-term leys can contribute to improved aspects of soil fertility, but that the magnitude of these effects is site-specific and may be influenced by initial soil properties.
Mouldboard ploughing has been associated with a loss in soil quality, while reduced tillage is often reported to result in crop yield declines. Occasional ploughing every few years could be an attractive compromise, but it remains unclear whether such a system results in a combined benefit of improved crop yield and soil quality. Here, we present data from a 43-year old field experiment on a clay soil in central Sweden. We analysed how three different tillage systems – annual mouldboard ploughing, continuous shallow tillage, and shallow tillage with occasional mouldboard ploughing – affect crop yields and soil properties with the objective of assessing joint response patterns between crop production and soil quality indicators reflecting soil structure, soil organic carbon storage, and habitat for soil biota. Crop yields were not affected by the tillage systems. Characteristics of the soil pore system and soil biota were similar in the occasional ploughing and annually mouldboard ploughed systems. Shallow tillage significantly altered microbial community composition relative to ploughed treatments, increasing bacterial and fungal abundances and reducing diversity in the upper topsoil layer, likely due to stratified soil carbon stocks. There was also a higher proportion of biopores in shallow tillage, which could be advantageous during dry spells that are expected to become more frequent and severe with climate change. Nevertheless, there were only small effects on water retention, biomass of nematodes and earthworms, and most of the abiotic soil properties. We conclude that occasional ploughing did not offer advantages at our site, and our results show that no system improved yield and all soil quality indicators simultaneously.
Context and Objective Nutrient use efficiency depends on factors including soil nutrients, and the corresponding root system architecture (RSA) adaptations. The preceding crop (precrop) can alter soil nutrient levels, affecting crop nutrient accumulation and RSA, with further variation by region and variety. This study investigated how region, year, precrop and genotype were associated with nutrient uptake, RSA, and yield in on-farm winter wheat trials. Methods Field trials of winter wheat were conducted in three Swedish regions over four years in paired on-farm fields. In each region–year combination, one field followed a cereal precrop and one a dicot precrop. RSA and nutrient concentrations were measured, then scaling exponents and hypervolumes were calculated to assess nutrient profiles. Results and Conclusions Nutrient profiles of wheat differed consistently between fields following cereal and dicot precrops. Fields following dicot precrops had higher calcium (Ca) and magnesium (Mg) concentrations, whereas phosphorus (P) concentration was higher after cereal precrops. Potassium (K) accounted for 46% of the total normalised random-forest importance for variation in Jaccard similarity among four-dimensional nutrient hypervolumes and strongly influenced element scaling exponents. Higher K concentrations correlated with nodal root number after an oilseed rape precrop and with yield after a wheat precrop. Nodal root angle also strongly correlated with P concentrations, with the strength and direction of these correlations varying by growth stage & precrop. Significance The findings emphasise the importance of taking environmental and management factors - particularly crop rotation, regional variations, and field management history – into consideration to optimise nutrient use efficiency and improve wheat yield over diverse regions and cropping practices. Understanding these interactions can guide agricultural practices and allow for better breeding for RSA traits.
Teaching Environmental Assessment (EA) in higher education is both challenging and essential, given its applied, interdisciplinary nature and close connection to evolving practice. While previous studies highlight recurring challenges in EA teaching, such as dispersed course structures, weak links to research, and ambiguities in how EA is positioned within academic programmes, they tend to address these aspects separately rather than as interrelated conditions. Drawing on literature analysis and qualitative interviews with teachers in Sweden and Germany, the study examines what teachers aim to convey, how they teach, and the factors that shape their pedagogical choices. Conceptually, it proposes an analytical framework that integrates teacherrelated, subject-related, student-related, and contextual dimensions, emphasising how teachers perceive and navigate them. In this sense, EA teaching is understood as a navigated practice shaped by how teachers respond to the conditions within which they work. The findings show that EA teaching shares a number of common aims and understandings across countries. Nevertheless, the teaching is also diverse and at times fragile. Teachers' responses to constraints, including limited resources, uneven access to EA knowledge and networks, and context-specific demands, play a central role in shaping what is taught. At the same time, the interdisciplinary nature of EA offers significant opportunities for integrating theory and practice. The study highlights the need to move beyond prescriptive accounts of EA education towards supporting teachers' situated practices and their capacity to make informed pedagogical choices under varying conditions.
Agroecological approaches harnessing in-field biodiversity have been highlighted as a sustainable way to reduce yield gaps, but long-term assessments of their ability to buffer production from weather extremes and increasing interannual and intraseasonal climate variability are scarce. Here, we analyze a 12-year dataset from 642 control vs. push-pull maize field pairs in western Kenya, where long-term climate trends include increasing temperatures and intensifying drought and rainfall. In push-pull, maize is intercropped with a fodder legume that improves soil fertility, suppresses weeds, and deters pests, and is bordered with fodder grasses attracting and suppressing the pests. We assess interactions between push-pull and climate effects on yields, stemborer pest damage and densities of parasitic weeds during the long and short rainy seasons, and how these drive push-pull effects on yield. Push-pull maize yields were always higher than control yields, but varying climate conditions affected the two field types differently. During the long rainy seasons, differences between push-pull and control yields were higher in years with high temperatures. Yield benefits of push-pull were also higher in years when dry spells were longer early in the long rainy season. During the short rainy seasons, push-pull increased yields, particularly when accumulated seasonal rainfall was optimal, while still doubling yield under very low or very high precipitation. Interactions between push-pull and climate variables were partly mediated by pests and weeds. Our results show that smallholder maize production using push-pull not only increases yields but also buffers adverse effects of weather extremes that are already becoming more frequent and intense.
