Agroscope

Abstract. Nitrogen (N) is essential for agricultural productivity, but excessive N inputs result in substantial losses to the environment. Conducting N assessments at national scales is challenging because observational data are limited, especially over long time periods. Here we compiled detailed datasets and performed high-resolution biogeochemical modelling to quantify N budgets for Switzerland's diverse agricultural ecosystems over four decades. Between the 1980s and the 2010s, N use efficiency improved from 47 % to 57 % in croplands and from 63 % to 71 % in grasslands, while losses through leaching and gas emissions decreased by 24 % in croplands and 4 % in grasslands. These improvements are closely linked to the implementation of national-scale agri-environmental policies that reduced fertilizer use in the 1990s. However, despite increased efficiency, cropland soils experienced substantial N depletion between 1995 and 2011 (−23 kg N ha-1 yr-1) in croplands. Our results demonstrate that policy reforms have improved agricultural system functioning and reduced losses, but also reveal risks associated with unbalanced soil N, underscoring the need for integrated N management for sustainable agriculture.

Research for Development support to smallholder farming systems is, with 70-90% of the global public and philanthropic funds, heavily skewed towards technical solutions i.e. seeds, fertilizers, technologies; while it is people and social systems that make or break “change”. In their decision-making, smallholders are often restricted by a lack of knowledge to fully and sustainably use the potential of their agricultural resources. In low-and-middle-income countries extension services are in place to fill knowledge gaps, yet these are chronically understaffed, farm households are often remote, extension budgets limited and language barriers exist. Digital extension tools are meant to serve as a low-cost, innovative way to reach more farmers. In practice, most digital extension tools have a low social fit: they are inaccessible (low digital literary, poor network, unaffordable), commercial (non-impartial) and non-inclusive (women less frequently owning smartphones), resulting in a limited uptake and impact. As part of the CIRNA project (CIRcularity of Nutrients in Agroecosystems and co-benefits for animal and human health), we analysed phone ownership and use for agricultural extension in Kenya and Uganda. 99% of the households we interviewed owned a basic (feature) phone, while smartphone ownership was much higher in Kenya (82%) than in Uganda (28%). We teamed up with a Social Enterprise from Kenya, specialized on inclusive ICT solutions for development, to create two locally grounded digital extension pathways for smallholders: An AI-driven WhatsApp chatbot for Kenya, capitalizing on higher smartphone adoption, and an Interactive Voice Response (IVR) hotline for Uganda to ensure accessibility for feature phone users. The chatbot in Kenya has an SMS dial-in option, too, so also feature phone users can participate. The extension tools are built on a social business model where revenue from content scaling is re-invested into the platform. Early demand testing in Uganda has already engaged over 29,000 farmers, signalling a robust appetite for the proposed digital advisory service. We explore the potential of these tools to not only "scale out" numbers but "scale deep" by impacting social norms, specifically targeting women and youth to ensure inclusive development.

Phosphorus (P) is essential for plant growth, but excessive accumulation in soils can pose environmental risks, particularly through losses into water bodies. However, despite large spatial variability in P concentration and availability, no nationwide map of soil P exists for Switzerland. Moreover, knowledge of the relative importance of management-related factors compared to soil chemical and pedoclimatic drivers on the distribution of total and available P remains limited.This study aims to predict and explain the distribution of total and available P pools in Swiss topsoils. For this purpose, we combined machine-learning approaches (ML) using Random Forests with model interpretation based on Shapley values to identify the main drivers controlling the P distribution. As model input, we used total P data measured at 960 sites of the Geochemical Soil Atlas of Switzerland in combination with predictor variables representing land use, soil properties, as well as environmental and geological conditions. To further investigate P dynamics in agricultural soils, we integrated a dataset from the Swiss Proof of Ecological Performance (PEP) subsidy scheme, which comprises 14 years of soil analyses since 2010. Available P pools were operationally defined using CO₂ saturated water extraction as a proxy for immediately plant available P, and ammonium acetate - EDTA extraction (AAE10) representing a larger pool of exchangeable soil P. This dataset includes approximately 150’000 observations, allowing differentiation between arable land and grassland.As expected, total P concentrations are significantly higher in arable land and in pastures/grasslands compared with forests and alpine areas. Accordingly, interpretable ML measures, including Shapley values, indicate that land use is the most important predictor, followed by the presence of nutrients such as nitrogen (N), potassium (K), and sulfur (S). In contrast, soil chemical properties (e.g. pH, soil organic carbon) and proxies for pedoclimatic conditions, such as temperature or lithology, are less important for the prediction on a national scale.Across Switzerland, the lowest available P concentrations are observed in north-western and southern regions, whereas the highest concentrations were measured along the Swiss Plateau and in central and north-eastern Switzerland. While P concentrations extracted with CO₂ saturated water are similar between arable crops and grassland, arable soils exhibit systematically higher AAE10 extractable P. Further work will focus on identifying the main drivers of available P pools and their temporal changes across Switzerland, including data from remote sensing and other monitoring programmes.By combining spatially resolved geochemical data, interpretable machine learning approaches, and long-term agricultural monitoring data, this study provides a framework for identifying key drivers of the distribution of P pools in Swiss soils, thereby supporting targeted and sustainable nutrient management strategies.

Summary Agrobiodiversity is in decline. While the literature highlights the role of public policy in this process, a research gap remains concerning how policies can help reverse this trend by providing economic support to farms that value crop and varietal diversity. Based on desk research and expert interviews, this article first provides an overview of European and national policy instruments that can be used to economically support the promotion of agrobiodiversity on farms, focusing on seven European countries. Drawing on case study findings, it then presents a typology of local initiatives that combine these instruments with local measures to provide economic support to farms cultivating minor crops and traditional varieties. This support is primarily indirect, ranging from seed provision to market development, although most initiatives do not cover the entire value chain. The results underline the critical role of local authorities and confirm the value of public‐private partnerships in promoting crop and varietal diversity. They also emphasise the need for stronger coordination between policy measures and governance levels to support value chains that foster agrobiodiversity, and call for further research to assess how the combined support of policy instruments and local measures contributes to new business models at farm level.

Pollinators are a diverse group of organisms – insects, mammals, birds and, to a lesser extent, amphibians, reptiles and even snails – that support plant communities and are the foundation of global food systems. Scientific research over the past 10-20 years has clearly shown that in some parts of the world they are declining, leading to significant changes in ecosystem functioning. Despite the great interest of a large number of scientific teams around the world in studying various aspects of pollinators and pollination processes, there are still not enough specialised academic journals whose main focus is this. The journal “Advances in Pollinator Research” (APR) was founded to transform the way pollinator science is published and shared, and consequently translated into real action. APR offers the scientific community an opportunity to publish in a state-of-the-art way biological, ecological, socio-economic and management aspects of pollinator health. The journal bridges basic and applied science, linking molecular biology, ecology, evolution, conservation, agroecology, ecosystem services, behavioural, economic, and social sciences with policy development, agricultural management, commercial pollinator management practices, and community-based conservation.

How diverse pollinator communities may promote resilience of crop pollination services in the face of increased climatic variability and to what extent such climatic resilience could be fostered through management options remains largely unexplored. Here, we address these research gaps using sweet cherry as a model crop. We quantified flower visitation by bee pollinators under the full range of variable temperature conditions throughout cherry flowering in 15 conventionally managed orchards chosen along a gradient of extensively managed agri-environment scheme meadows (AES meadows) in surrounding landscapes. Thermal niches for a total of 17 important cherry pollinator species based on 11’483 flower visits were determined. Thermal niche complementarity and resilience of wild bees visiting cherry (i.e. the summed temperature niches of species weighted by their flower visitation frequency), but not thermal niche breadth, was enhanced by the proportion of AES meadows in the landscape. We identified wild bee diversity and the broad thermal niches of bumblebees as important drivers of an enhanced resilience. Fruit set as a proxy of cherry yield was exceptionally low and not significantly influenced by thermal resilience or other tested bee community variables. We hypothesise that adverse weather conditions during fruit development were the main cause. Our study highlights the important role of thermal niche breadth and complementarity of diverse wild pollinator communities in providing resilience to crop flower visitation under variable climatic conditions. Our findings show that agri-environmental interventions can enhance such climatic response diversity and niche complementarity of wild crop pollinators underpinning resilience of crop pollination. • Thermal species niches for a total of 17 important bee cherry pollinator species were determined. • Agri-environmental scheme meadows increase diversity, thermal niche complementarity and resilience of wild cherry pollinators. • Especially bumblebees with broad thermal niches buffer pollination services during cool periods. • Important role of climatic response diversity of wild pollinators underpinning stability of crop pollination.

• Passive cooling blanket (PCB) reduced temperature by a maximum of up to 20 °C. • PCB shows consistent performance across diverse climatic conditions and crop types, maintaining high humidity and stable temperatures. • PCB extended fresh produce shelf life and significantly reduced postharvest losses. • PCB reduced vendor tomato losses by approximately 92% in Uganda. • 97% of Kenyan farmers showed interest in adopting the PCB for improved storage. This study evaluates the effectiveness of evaporative passive cooling blankets (PCBs) in reducing postharvest losses and extending the shelf life of fruits and vegetables in Kenya, Uganda, and Nigeria. Using locally available natural materials such as sawdust and charcoal, PCBs were deployed under diverse climatic conditions to assess their capacity for temperature reduction and humidity control. In Kenya, PCBs achieved temperature reductions of up to 10 °C and maintained relative humidity near 95 %, reducing postharvest losses of vegetables by up to 45 % and extending shelf life by 3–4 days. In Uganda, PCB application along the local tomato supply chain lowered average air temperatures by up to 2 °C, with peak reductions of up to 20 °C. This intervention extended tomato shelf life by 2 days and improved market outcomes, although performance was moderated by rainy-season conditions. In Nigeria, PCBs reduced average air temperature by 5 °C, increased relative humidity by 25 %, and decreased tomato weight loss and rot by 32 % and 20 %, respectively. Overall, the use of PCBs reduced postharvest losses by approximately 30 % across the three countries. These findings demonstrate a scalable, low-cost, electricity-free cooling solution suitable for smallholder farmers in Sub-Saharan Africa. By validating PCB performance under real field conditions, this study highlights the potential of passive evaporative cooling technologies to enhance food preservation, reduce waste, and improve food security in resource-limited settings.