The benefits of integrated crop-livestock systems (ICLS) have been widely discussed, but their application remains limited. The effects of agricultural characteristics and spatial distribution in a landscape on the development of ICLS are not well understood. This study aimed to better understand the current specialization of farming systems to support ICLS development, by capturing the diversity of farms and their spatial distribution patterns. It developed a spatially explicit farm typology and map of the proportion of types throughout the study area, using a 300-households survey data set from Quzhou, a typical agricultural production county on the North China Plain. Also, it identified six distinct farm types characterized by the degree of specialization, management and farm size. Environmentally and socioeconomically oriented variables were used to further quantify farm types. Three features in these farm types were identified as being relevant in the context of ICLS, that is overuse of fertilizer, the decoupling of crop and livestock production, and a strong dependence of specialized livestock farms on feed import. Farm types were unevenly distributed across the study area, indicating regional specialization and a spatial decoupling of crop and livestock production. The paper discusses driving forces behind the different farm types and their implications for ICLS. New guiding policies are needed to limit strong regional specialization and facilitate ICLS to ensure a balanced crop-to-livestock ratio and distribution at a subregional scale. Overall, this study may help to contextualize future ICLS designs to local conditions and support agricultural transition policies and rural development on the North China Plain.

In greenhouses, fossil CO2 is commonly used to increase crop yield. Regardless of future availability, which is expected to decrease, fossil CO2 enrichment is unsustainable. However, without CO2 enrichment, yields per unit area may decrease, increasing the energy intensity of produce. Non-fossil (‘short-cycle’) CO2 may prevent this, but its provision also requires energy. Here, CO2 sources are quantified from an energy perspective, using a new methodology applied to three sources: (1) biogenic CO2, (2) direct air capture (DAC), and (3) ambient CO2 from ventilation. The energy demand of CO2 has two aspects: (1) a ‘fixed’ aspect, from generating or supplying the CO2, and (2) a weather-dependent aspect, from heating displaced air in the greenhouse. Both affect the environmental impact of CO2 enrichment, depending on the carbon intensity of the energy source. Approximately 1% volumetric CO2 concentration is sufficient to make weather-dependent energy demand negligible, which makes greenhouses an interesting destination for biogenic CO2. The implications of non-fossil CO2 are calculated using year-long simulations, comparing the three sources' effect on yield and energy intensity of produce. Efficiency and the potential to increase it are investigated with Lorenz curves, revealing that most additional yield comes from a small minority of CO2 introduced into the greenhouse. This study consistently showed the following: the role of ambient ventilation in CO2 provision is minor, the energy efficiency of DAC should be prioritised rather than high outgoing CO2 concentrations (>1%), and biogenic CO2 is an energetically favourable option to be explored depending on locally available sources.

Northwest Europe experienced considerable increases in wheat yield until the mid-1990s, but progress has remained stagnant since then. Estimating the relative contributions of improved genetics, historical climate change and agronomic management to this yield plateau is required to understand the feasibility of yield increases in the future. Analysis of high-quality experimental data revealed yield gains due to improved genetics of 74–84 kg ha−1 yr−1 during the period 1994–2016. Thus far, yield gains due to historical climate change of 26–60 kg ha−1 yr−1 were estimated over the same period using a well-validated crop model across regions, soil types and cultivars. Given the absence of genetic and climatic yield ceilings, we conclude that agronomic management is responsible for the wheat yield plateau in northwest Europe, contributing to unrealized potential yield gains of 67–114 kg ha−1 yr−1. Breaking the yield plateau will require due attention to agronomic constraints at the farm level and continued monitoring of genetic gains and climate change impacts on wheat yields. Wheat yields in northwest Europe have plateaued since the mid-1990s. This study finds that no ceiling in genetic yield potential has been reached and that climatic conditions have not constrained wheat yields across high-yielding environments in the region thus far; suboptimal agronomic management is responsible for unrealized wheat yield progress of 67–114 kg ha−1 yr−1 during the period 1994–2016.

The Dutch agricultural sector's orientation towards exports attracts divergent views. Whereas some stakeholders advocate maintaining exports to help 'feed the world', others question the validity of this rationale and its environmental consequences. Here we assess the Netherlands' net-export potential using an agroecological food system model. We find that producing the food groups currently consumed domestically would require all available land in the country. Even with a shift towards more plant-based diets, the potential to export food remains limited if land is also required for strengthening natural ecosystems and fostering the biobased economy. These findings challenge the economic 'feeding the world' narrative and underscore the need for an ecological perspective. Our approach can be applied to other regions, helping to redefine their role in the global food supply.

Sub-Saharan Africa (SSA) has the world's largest projected increase in demand for food. Increased dependence on imports makes SSA vulnerable to geopolitical and economic risks, while further expansion of agricultural land is environmentally harmful. Cereals, in particular, maize, millet, rice, sorghum, and wheat, take nearly 50% of the cropland and 43% of the calories and proteins consumed in the region. Demand is projected to double until 2050. Here, we assess recent developments in cereal self-sufficiency and provide outlooks until 2050 under different intensification, area expansion, and climate change scenarios. We use detailed data for ten countries. Cereal self-sufficiency increased between 2010 and 2020 from 84 to 92% despite the 29% population increase. The production increase was achieved by increased yields per hectare (44%), area expansion (34%), and a shift from millet to the higher yielding maize (22%). Outlooks for 2050 are less pessimistic than earlier assessments because of the larger 2020 baseline area, higher shares of maize and somewhat less steep projected population increase. Yet, to halt further area expansion, a drastic trend change in annual yield increase from the present 20 to 58 kg ha-1 y-1 is needed to achieve cereal self-sufficiency. While such yield increases have been achieved elsewhere and are feasible given the yield potentials in SSA, they require structural changes and substantial agronomic, socioeconomic, and political investments. We estimate that amounts of added nitrogen need to at least triple to achieve such yield improvements, but it is essential that this comes with improved context-specific agronomy.

Potato, the fourth most important food crop globally, is increasingly grown in subtropical regions, and India is now the second largest producer. Subtropical climates will be affected by the intensified occurrence of heatwaves and droughts due to climate change. Crop growth models (CGMs) are critical tools to predict and build strategies for crop climate adaptation, with the World Food Studies (WOFOST) being among the most widely used in this regard. However, WOFOST-Potato was developed based mainly on data acquired under mild or optimal weather conditions, which impedes its predictive ability in relatively hotter subtropical climates such as India. Experiments from subtropical regions can be used to broaden WOFOST applicability. Comparing the WOFOST processes that dominate crop growth during the growing season in temperate versus subtropical climates may provide insights to improve WOFOST and identify key climate adaptive traits. Systematic sensitivity analysis (SA) is useful for this purpose. Here, we applied three SA methods (local SA, Sobol and PAWN) to WOFOST-Potato to identify the key temperature-related processes responsible for simulating potato phenology and growth under hot conditions. We selected two locations with contrasting climates, i.e. the Netherlands (temperate) and India (subtropical). By computing time-dependent parameter sensitivities, we illustrate that the dominant processes change throughout the growing season. Sensitivity patterns differ fundamentally between the two locations. In the Netherlands, the leaf area index (LAI) and tuber yield (TWSO) were sensitive to development-related parameters, whereas in India, LAI and yield were predominantly sensitive to growth-related parameters. We find that time-dependent SA is able to capture the seasonal dynamics of WOFOST-Potato, and it is more insightful than the end-of-season SA to identify key parameters in subtropical environments. Building upon the global sensitivity analysis findings, we find that local sensitivity analysis still has added value to capture model behaviours driven by critical parameters. Based on our results, we argue that a combination of various time-dependent SA methods provides a robust approach to identifying the key processes of WOFOST-Potato in different environments. Our results indicate that the relationship between photosynthesis and temperatures in subtropical environments may need extra attention for modelling potato production.

The transition towards circular agriculture is seen as a way to improve the environmental sustainability of agriculture. As the next generation, young farmers play a crucial role in this transition, and understanding their perspective on circular agriculture is essential. Therefore, this paper aims to explore young farmers' perceptions of the transition to circular agriculture by (1) surveying their views and definitions of circular agriculture, (2) determining their implementation of circular agricultural practices and perceived barriers and (3) analysing the transformative potential of these practices. Data was collected through an online survey among 53 young farmers in the northern Netherlands, followed by a transformative potential analysis and reflective discussions. Findings, revealed high variability in whether young farmers view circular agriculture as a solution to agricultural challenges in the Netherlands. They were, however, relatively positive about circular agriculture as something that fits their businesses. We observed variation in which themes were associated with circular agriculture, indicating a lack of a consistent definition. While many circular agricultural practices have already been applied or are of interest, many of these practices exhibit low transformative potential. Almost all young farmers were confronted with systemic barriers concerning regulatory uncertainties and existing regulations. Creating an enabling environment for the implementation of circular practices requires supporting young farmers in adopting more transformative practices, overcoming systemic barriers, and providing a clear long-term perspective in which circular agriculture is embedded in a vision, or pathway, towards sustainable food systems.

Context: Accurately projecting crop yields under climate change is essential for understanding potential impacts and planning of agricultural adaptation in sub-Saharan Africa (SSA). Crop growth models and machine learning (ML) are often used, but their effectiveness is limited by data availability, precision, and geographic coverage in SSA. Objective: This study aimed to integrate ML with a process-based crop model to produce geographically continuous gridded crop yield projections while reducing uncertainties associated with standalone ML or crop growth models. As a case study, we implemented it to project the climate change impact on water-limited potential yield of maize across SSA. Methods: We developed an integrated system that combines ML with eco-physiological processes to estimate sowing dates and thermal times, ensuring that crop phenology is accounted for, thus improving potential rainfed yield simulations under varying environmental conditions. Random Forest and crop model-based algorithms are integrated in three steps: (i) RF1, a Random Forest model integrated with a sowing algorithm, designed to estimate the sowing window and sowing date; (ii) RF2, a Random Forest model combined with a crop model algorithm to estimate cumulative thermal time during the growing season, used to determine the timing of phenological stages; and (iii) RF3, another Random Forest model, trained based on eco-physiological principles applied in phases (i) and (ii), employed to simulate water-limited potential yield. The outcomes of the different steps of the framework under historical conditions were tested against reported data across SSA. Results and conclusions: For maize and historical climatic conditions, the framework delivers yields which differ less than 20 % of those simulated with a crop model with high-quality inputs, in 95 % of the cases. Our approach thus shows value for generating crop yield projections in data-scarce regions under historical climate, and under future climatic conditions which already feature today somewhere in SSA and for which the framework has been trained. Significance: Our approach can also be applied to other major food crops in SSA, under both current and climate change conditions. It allows testing the effect of adaptation of crop cultivars in terms of maturity group. Thus, it can be used for different crops and with far less data requirements compared to process-based crop models. It has the potential for significant applications in assessing climate change impacts, guiding adaptation strategies, and supporting crop breeding programmes and policymaking efforts in SSA.

Europe is an important potato producer, showing a strong decline in areas and increases in yield over the past decades, but with large regional differences. This study aims to characterise current European potato production by analysing yields, revealing yield gaps (Yg), and assessing key factors that explain actual (Ya) and potential yields (Yw, for rainfed systems; Yp, for irrigated systems). We selected 13 key potato producing countries, jointly accounting for 90​% of the European potato area. Local data were used to simulate Yw and Yp, while Ya was retrieved from sub-national statistics. Then, we analysed main factors affecting yields using boundary line analysis on nitrogen input and crop water availability. Results showed that European potato production on current acreage can increase by 55​% when yields would increase to 80​% of their potential. The largest potential production gains featured in eastern Europe (59​% Yg, 59​% of potato area), thereafter western Europe (32​% Yg, 25​% of potato area), and smallest gains in northern and southern Europe (43​% and 45​% Yg, with relatively small acreages of 9​% and 6​%, respectively). Our analysis revealed that nitrogen input was a limiting factor in eastern Europe, while we found substantial overuse in some western European countries. Under rainfed conditions, water was the main limiting factor in relatively few potato cultivation areas. In irrigated areas, e.g. in southern Europe, irrigation water requirements to approach Yp are large, which becomes increasingly challenging. Insights from this study can be used to guide future development and innovation in potato cultivation across Europe.

CONTEXT: More nutrient cycling may be achieved by using less external inputs (feed, fertilisers) and reduce losses to the environment, especially in intensive farming systems. Yet, changes in on-farm management may have unintended consequences at higher aggregation scales due to potential trade-offs. OBJECTIVE: The objective of this study was to develop a multi-indicator and multi-level model which operates at farm and regional level to evaluate scenarios for improved nitrogen cycling. METHODS: A new model, based on nitrogen flow analysis, was used to compare five scenarios with the current situation as reference. The model was applied to a case study region, the Dutch province Drenthe including typical arable, pig, poultry, and dairy farms. In the scenarios, the proportion of manure digested for biogas production, and imported amounts of synthetic fertiliser and feed into the region were varied, as single measures or in combination. RESULTS AND CONCLUSIONS: Modelling results showed that digestion of manure for biogas production reduced total regional nitrogen losses and produced renewable energy. A 20 % decrease in synthetic nitrogen fertiliser application reduced crop yields only slightly and improved the regional nitrogen use efficiency and nitrogen cycling, as manure availability in Drenthe was sufficient to meet a large proportion of the total crop nutrient requirements. Combining multiple measures was most effective in increasing nitrogen cycling (+65 %), leading to reduced greenhouse gas emissions (-49 %) and an improved net energy balance (+84 %) from agriculture in Drenthe, with the largest contribution coming from restricting feed import (resulting in a reduction of the total livestock herd in the region). However, when livestock was reduced, more synthetic nitrogen fertiliser was needed to maintain crop yields. Our study also highlighted trade-offs: positive effects on nitrogen cycling, greenhouse gas emissions and nitrogen losses coincided with reduced food production and organic matter inputs to soils, with consequences for carbon stocks. Furthermore, results for the whole region were not always representative for each farm type. SIGNIFICANCE: The results demonstrate that our systems approach, quantifying multiple indicators simulta- neously at farm and region level, can provide a better understanding of benefits and trade-offs when aiming for an agricultural system which is productive, but with reduced emissions to the environment. The developed model is generic and can be applied to evaluate alternative nitrogen cycling scenarios in other European regions with only little parameterisation needed from publicly available data.

Sustainable production of sufficient and healthy food requires efficient use of agricultural inputs. In many regions of the world with intensive agriculture and relatively small yield gaps, this calls for a reduction of external inputs (fertilizers and pesticides) while maintaining yields. Ecological intensification, defined as the use of practices that enhance on-farm ecosystem services to reduce external input requirements, has been proposed as a strategy to help achieve this. However, the effects of ecological intensification are context- and input-dependent, creating uncertainty on its effectiveness and feasibility. Here, we introduce the concept of an ‘ecological yield gap’ to provide a common analytical framework to strengthen collaboration between agronomists and ecologists in assessing the contribution of ecosystem services within the wider array of inputs, management practices, technologies, and biophysical limits that determine on-farm crop yields. We define the ecological yield gap as the yield increase that could be achieved in a given context (climate x soil x cropping system), and at a given input level, by increasing the delivery of ecosystem services via ecological intensification practices that support crop growth and substitute external inputs. We provide empirical examples of such practices, including crop diversification, service crops, and organic amendments that can increase the use efficiency of mineral fertilizers and suppress pests, weeds and diseases. The potential of these practices to narrow the ecological yield gap and their feasibility at farm level depend on how the ecosystem services they provide interact with other aspects of the farming system and requires analysis at farm level. This perspective paper aims to facilitate a shared research agenda among agronomists and ecologists to develop complementarity between ecosystem services and inputs at field and farm levels.

Integrated agricultural systems which connect crops, livestock, industry, and consumers through recycling of co-products potentially reduce losses to the environment and utilise inputs more efficiently. This study assesses how co-product use in agriculture affects food production and its environmental performance in multiple European regions, and evaluates how regional context affects the optimum use of available co-products. An exploratory nitrogen flow model, including quantification of greenhouse gas (GHG) emissions, effective organic matter (EOM) inputs, and energy use, was applied to assess co-product use options across four European regions: Ariège (Southern France, A-FR), Drenthe (Northeastern Netherlands, D-NL), Fife (Eastern Scotland, F-SC), and the inner Limfjord catchment (Northwestern Denmark, L-DK). Various use options were assessed for three co-product types: manure, crop residues, and household organic waste. In L-DK and D-NL, more manure was available than in A-FR and F-SC, which strongly affected outcomes of the alternative use options. Manure digestion reduced GHG emission (ranging from -2.0 % to -19.8 % across regions), but EOM soil inputs decreased (-1.1 % to -25.3 %) compared to untreated manure. Crop residue use was important in regions with more cereal production (L-DK and F-SC), improving the regional energy balance when digested (+11.1 % to +195.5 %), or increasing EOM inputs when retained (+2.8 % to +15.9 %) compared to residue removal. What happened with household organic waste had less effect on the indicators, because of the small volumes compared to manure and crop residues. Our study suggests that regional context strongly affects the impact of co-product use options on environmental indicators. Prioritization of co-product utilization should mainly consider co-product type and its regional availability.

CONTEXT: Understanding the potential and impacts of closing resource loops on different spatial scales requires a food systems approach with local context of the biophysical production environment and food demand. OBJECTIVE: We investigated how local sourcing of food affects land use and land use patterns in a circular food system in the Netherlands. METHODS: We used the food systems optimization model FOODSOM, along with site specific crop yields for a range of food and feed crops, and compared scenarios with varying levels of food self-sufficiency of Dutch provinces. RESULTS AND CONCLUSIONS: Without restrictions on local sourcing, the Dutch population could be fed a healthy diet using 54 % of current agricultural land, increasing by similar to 50.000 ha to 57 % when sourcing 90 % of consumed food locally within each province. Increasing provincial (local) sourcing shifted land use in the Netherlands from high yielding clay and sandy soils in provinces with low population density, to less suitable peat and wet soils in provinces with a high population density. The total land requirement for the Netherlands remained stable up to 50 % of local sourcing, as this could be achieved for all provinces while avoiding lower yielding soils. SIGNIFICANCE: We show that there is sufficient land to meet food requirements of a healthy diet in the Netherlands. Circularity at the provincial scale requires the use of less suitable land, but only slightly increases total land use area, owing to the high fertility and relatively small yield differences across the country. In countries with larger yield differences between soils, local sourcing would increase land use more drastically. The targeted degree of local sourcing may also depend on how the additional land use affects net greenhouse gas and nutrient emissions and biodiversity when compared to more transport and production elsewhere.

Context: Transitioning to future circular economies and food systems will increase demand for biomass in society. Residual streams, which include food loss, food waste and by-products (e.g., rapeseed meal) from agriculture and food production are a valuable source of biomass in more circular food systems. It is currently unclear if and whether these residual streams should be utilised optimally: as animal feed, composted as organic fertiliser or for anaerobic digestion to produce biogas (methane) and digestate (fertiliser) to minimise environmental impacts from food systems. Objective: Our aim is to understand which residual streams are to be utilised as animal feed, compost or for anaerobic digestion in circular food systems to achieve minimum agricultural land use and greenhouse gas (GHG) emissions under scenarios with different dietary preferences. Methods: Taking the Netherlands as a case study, we employed the FOODSOM model, an iterative linear optimisation model of a circular food system in the Netherlands. FOODSOM minimises agricultural land use or GHG emissions while meeting the dietary requirements of the population. Four scenarios based on two different human diets and two food system objectives (i.e., minimise land use or GHG emissions) were developed. Results & conclusions: Our results show by-products should be fed to livestock when aiming to minimise agricultural land use and GHG emissions, food loss and waste is best fed to livestock when minimising land use, but composted or digested when minimising GHG emissions. The decision to compost or digest food waste depends

Northwest Europe experienced considerable increases in wheat yield until the mid-1990s, but no further progress was reported since then. Estimating the relative contributions of improved genetics, historical climate change, and agronomic management to this yield plateau is required to understand if yield increases are possible in future. Analysis of high-quality experimental data (1972-2013) revealed yield gains due to improved genetics of 90 kg ha-1 yr-1. Thus far, yield gains due to historical climate change (1972-2016) of 55 kg ha-1 yr-1 were estimated using a well-validated crop model. Given the absence of genetic and climatic yield ceilings, we conclude agronomic management is responsible for the yield plateau in Northwest Europe, constraining yield progress by 100 kg ha-1 yr-1 or more. Breaking the wheat yield plateau in Northwest Europe will require incentives for farmers to prioritize investments in wheat production over other, more profitable, crops.

Context: Intensification of arable farming in Northwest Europe has led to high yields. However, inadequate use of external inputs such as nutrients, irrigation water and crop protection products has contributed to several environmental problems, such as nitrate leaching and losses of crop protection products. There is a need to reduce environmental losses and contribute to a more circular and sustainable agriculture in Northwest Europe. Objective: Here, we take ware potato production in the Netherlands as an example cropping system to assess if there is scope to reduce input levels and environmental impact of nutrient, water and crop protection product use without compromising yield. Methods: We determined variability in use and use efficiency of nitrogen (N), phosphorus (P), potassium (K) and pesticides as well as water productivity (WP) and yields of 96 on-farm ware potato fields in the Netherlands, on both clay and sandy soils. In addition, we assessed if relatively high performance could be achieved on multiple environmental indicators simultaneously. Results and conclusions: Average N surplus was 265 kg N ha(-1) on clay soils and 139 kg N ha(-1) on sandy soils and varied among fields by a factor three. Phosphorus and K input exceeded P and K output on clay soils by 33 and 105 kg ha(-1), respectively, while on sandy soils P and K balances were close to zero. Mean WP was 43 kg dry matter (DM) mm(-1) ha(-1) and ranged from 30 to 60 kg DM mm(-1) ha(-1) for both soil types. In terms of crop protection product use, lowest and highest use differed by a factor four. Unexpectedly, yields did not increase with higher input rates, suggesting that lower input rates are sufficient to obtain current yields. Consequently, input rates were the most important drivers to explain variability in resource use efficiency and environmental impacts. At the same time, a comparison across multiple indicators simultaneously showed that it was possible to achieve relatively high yields with relatively low N surplus, high WP, and low crop protection product use. Hence, environmental impact could decrease substantially if all fields performed similar to the best performing fields. Significance: This study showed that it seems feasible to maintain high yield levels while reducing resource use in a substantial share of the potato production fields in the Netherlands. If put in practice, this will reduce losses to the environment and therefore contribute to a more sustainable but still productive agriculture.

Data was collected at two field locations in the Netherlands: on the clayey soils in Lelystad and the sandy soils of Vredepeel during 2019 and 2020. The original aim of this dataset was to calibrate and evaluate crop growth models for estimating potential, water-limited and nitrogen-limited yield levels for modern potato cultivars. Therefore, treatments include different cultivars, irrigation regimes, nitrogen fertilization, and light interception. During the two seasons extensive data was collected either passively, via non-destructive or via destructive measurements. Passive measurements consisted of weather and soil moisture data and were taken continuously throughout the season. Non-destructive data was collected on photosynthesis, reflection/light intensity, SPAD chlorophyll values, plant height, crop phenology, and groundwater level roughly every other week throughout the seasons. Destructive measurements were taken on biomass (leaves, stems and tubers), leaf area, NPK content (leaves), and the number of tubers between five and seven times per season. Additionally, during the final harvest data was collected on the tuber size distribution, marketability, and NPK content of the tubers.