Agronomy for Sustainable Development最新文献

In Sub-Saharan Africa, dairy value chains’ stakeholders face many challenges and have expectations for change. Step-by-step innovation design methodologies and multi-stakeholder innovation platforms are implemented to drive changes desired by stakeholders. We assumed that combining these two approaches would reinforce the potentiality of achieving the changes. To the best of our knowledge, the specific mechanisms and actions involved in such a combination are poorly documented. This study contributes to fill this gap by reporting on modalities of engagement, collaboration, and change generation with stakeholders of dairy innovation platforms deriving from a step-by-step innovation design approach that is embedded within an overall loop-structure dynamic and accounting for three levels of stakeholders’ engagement. We applied this step-by-step approach as part of the “Africa-Milk project” on ten dairy innovation platforms located in four African countries (Senegal, Burkina Faso, Kenya, and Madagascar). The approach was led by a core team and applied adaptively across the various innovation platforms, according to both their organizational context and objectives. In this paper, we captured the lessons learned along the key implementation stages of the approach (i.e., engagement, action, and assessment) and regarding the type of stakeholders involved. Our results show that the initiation of the engagement highly depends on the pre-existence of an innovation platform. The action stage proceeds then through either cascading actions or parallel actions. Finally, the outcome assessment stage enables to identify different types of changes induced by the approach (i.e., changes in practices, interactions, capacities, and opinions). Owing to its adaptability, the overall loop-structure of the approach enables practical adjustments and reflexivity to best meet the needs of innovation platform stakeholders. This study paves the way to implement co-design of innovation approaches to broader multi-stakeholder platforms involved in agri-food system transformations.

To solve soil fertility problems, most smallholder farmers in sub-Saharan Africa use fallow periods. However, population growth along with land shortage tends to shorten the duration of fallows, resulting in a steady decline in soil fertility. Although nitrogen (N) plays a key role in soil fertility, current methods for maintaining N supply in cropping systems are inadequate, especially in N poor soils. Addressing this issue is crucial for improving agricultural productivity and reducing environmental impact. The objective of this study was to explore innovative ways to maintain N supply in N poor soils by identifying the appropriate levers and practices. We designed a general model describing N cycle in a cropping system in a humid savanna in Ivory Coast. We examined the impact of different processes involved in N cycle, including mineralization, nitrification, and fallow characteristics on the yield of a crop such as corn. Our study innovatively assesses the benefits of incorporating nitrification inhibition into traditional African cropping systems and provides a modelling tool to assess its impact. The model confirms that in low input agricultural systems, soil fertility is maintained by the increase in soil organic matter during fallow and its subsequent mineralization. We showed that variation in nitrification during the cropping cycle (fallow-crop) does not have a significant effect on corn yield. However, with the addition of N fertilizers, nitrification inhibition significantly increases crop yield. Indeed, nitrification inhibition increases the efficiency of fertilizer use, which reduces losses of N fertilizer. Furthermore, legume-based fallow is able to increase corn productivity much more than a nitrification-inhibiting fallow regardless of the length of fallow periods. Finally, the models suggest that using nitrification-inhibiting grasses as cover crops for corn would be beneficial if mineral N fertilizer is used.

As warm season droughts increase in frequency due to climate change, causing severe yield losses especially among cereal crops, European agriculture is in dire need of adaptation. While agroforestry is widely regarded as a key adaptation measure, little is known on how yield performance is influenced by changing water availability in temperate regions. Therefore, we assessed the yield dynamics of five winter crops (winter wheat, triticale, winter barley, winter pea, and rapeseed) during seven growing seasons (2012 to 2023) in a well-established (since 2007) alley cropping agroforestry trial site in Southwestern Germany. The trial integrated three different agroforestry practices in a randomized block design: (i) willow short-rotation coppice, (ii) walnut trees for nut production, and (iii) diverse hedgerows. The relationship between crop yield and climatic water balance was analyzed using a linear mixed-model. In this unique long-term comparison, we demonstrate that individual alley cropping practices exhibited distinct yield patterns with increased distance to tree rows. In contrast to the willow short rotation coppice, walnut and hedgerows did not evoke significant winter crop yield declines at proximity. While in the walnut plots yields did not significantly vary with distance to tree rows, yields adjacent to hedge rows declined significantly towards the alley center. Moreover, tree rows contributed to stable crop yields under fluctuating water availability in their proximity and up to the alley center on their leeward side while yields significantly varied with changing climatic water balance on the windward side. Our results underline the potential of agroforestry to sustain yields in the face of increasingly variable water availability, further substantiating the contribution of alley cropping agroforestry for farming systems’ resilience to increasingly variable weather conditions. They moreover contribute to planning and policy support for advancing agroforestry as a climate smart solution in temperate regions. 

The impact of a changing climate on crop and tree growth remains complex and uncertain. Whilst some areas may benefit from longer growing seasons and increased CO₂ levels, others face threats from more frequent extreme weather events. Models can play a pivotal role in predicting future agricultural and forestry scenarios as they can guide decision-making by investigating the interactions of crops, trees, and the environment. This study used the biophysical EcoYield-SAFE agroforestry model to account for the atmospheric CO₂ fertilization and calibrated the model using existing field measurements and weather data from 1989 to 2021 in a case study in Northern Ireland. The study then looked at two future climate scenarios based on the representative concentration pathways (RCP 4.5 and RCP 8.5) for 2020–2060 and 2060–2100. The predicted net impacts of future climate scenarios on grass and arable yields and tree growth were positive with increasing CO₂ fertilization, which more than offset a generally negative effect of increased temperature and drought stress. The predicted land equivalent ratio remained relatively constant for the baseline and future climate scenarios for silvopastoral and silvoarable agroforestry. Greater losses of soil organic carbon were predicted under arable (1.02–1.18 t C ha⁻¹ yr⁻¹) than grassland (0.43–0.55 t C ha⁻¹ yr⁻¹) systems, with relatively small differences between the baseline and climate scenarios. However, the predicted loss of soil organic carbon was reduced in the long-term by planting trees. The model was also used to examine the effect of different tree densities on the trade-offs between timber volume and understory crop yields. To our best knowledge this is the first study that has calibrated and validated a model that accounts for the effect of CO₂ fertilization and determined the effect of future climate scenarios on arable, grassland, woodland, silvopastoral, and silvoarable systems at the same site in Europe.

Transitioning to a fossil fuel free society requires an increase in solar energy production. However, expanding solar power to farmland competes with food production. Additionally, climate change threatens food security and leads increasingly to yield losses. Agrivoltaic systems produce solar energy and food on the same field, while sheltering crops. In agrivoltaic systems, crops grow in a protected environment with reduced solar irradiance, a modified microclimate, and a potential physical cover protecting against hail damage. The agrivoltaic system may help safeguard crop yields from extreme weather events such as frost during flowering or sunburn during heat waves. Studies on agrivoltaic fruit production have previously focused on raspberry or apple. However, multiyear field trials are often lacking, and no study has described agrivoltaic pear cultivation. This research describes the multiyear effect of agrivoltaics on pear fruit, revealing that a predictable fruit yield and quality can be attained under solar panels in a temperate maritime climate. Tree rows were fitted with semi-transparent monofacial c-Si photovoltaic modules at a ground coverage ratio of 25.45%. Across three growing seasons, we recorded a 24% light reduction at canopy level. Agrivoltaic pear trees yielded 15% less than the reference control plots in 3 consecutive years. Flowering and fruit-set were unchanged, while agrivoltaics reduced leaf flavonoid levels. The leaf photosynthetic performance was identical, yet delayed leaf senescence under agrivoltaics suggests an adaptation to the modified environment. Agrivoltaics impacted fruit shape, as there was an increase in the number of bottle-shaped pears and a reduction in caliber. Other fruit quality traits were unaffected, including postharvest ethylene production. A land equivalent ratio of 1.44 was reached in the agrivoltaics orchard. This study demonstrates that agrivoltaics hold potential for pear production under temperate climates and highlights how pear productivity and quality is predictable when compared with conventional cultivation methods.

Agroecological practices are largely recognized as one way of engaging social actors in the co-design and transformation of food systems towards sustainability. Such comprehensive approaches are difficult to evaluate using conventional metrics of agronomic and economic performance, which are only partial judges of the changes they enable. Holistic evaluation frameworks are essential to capture the multidimensional impacts of agroecology and provide evidence for informed decision-making. Identifying methodological gaps remains critical for framework improvement. While systematic reviews on agroecology impacts exist for other regions, Southeast Asia lacks such analysis despite its agricultural importance and unique characteristics. This knowledge gap potentially undermines the effectiveness of agroecological initiatives across Southeast Asia’s diverse agricultural landscapes. In response to this gap, we carried out the first systematic literature review on this topic in Southeast Asia. Our review included 97 papers across diverse disciplines. More than a third of the studies were conducted in Indonesia, with agroforestry accounting for half of the reviewed papers. Comparative land use studies and field experiments each constituted one-third of the research records, with both approaches focused on the plot level. Quasi-experimental evaluations represented merely 5% of the total studies. Half of the studies analyzed impacts of agroecological practices on income, followed by biodiversity and yield; very few assessed socio-cultural indicators. Overall, positive impacts of agroecology were reported, focusing on biodiversity, input efficiency, and soil health. The few studies on integrated crop-livestock farming assessed more diverse impacts, including social values and diets. Key methodological gaps in the holistic evaluation of agroecology in Southeast Asia emerge from this review. Research limitations include predominant plot-level focus, insufficient methodological integration of evaluation approaches, and critically neglected social and cultural dimensions. Additionally, a contextualized definition of agroecology developed and embedded in Southeast Asia farming systems is needed to guide adequate characterization, evaluation and policy formulation. 

Weedy rice has recently emerged as a serious problem in Southeast Asia, despite the region’s long history of rice culture. Major economic losses have resulted from reduced yield, grain quality deterioration, and increased control cost. This review seeks to describe the complete set of circumstances leading to the sudden invasiveness of weedy rice in Southeast Asia. The paper begins with a timeline of weedy rice records in the region, along with the chronological sequence of the spread of modern rice technology. This is followed by a review of evidence of genetic interaction between cultivated, wild, and weedy rice. The consequence of the introduction of photoperiod insensitivity from modern rice varieties into the local cultivated-wild-weedy rice gene pool is analyzed. The influence of the agronomic practices of modern rice farming on the competitiveness, adaptation, and dispersal of weedy rice is reviewed. Detrimental effects of weedy rice on rice production are evaluated. The main finding is that weedy rice, like its wild ancestor, the common wild rice, is likely endemic to deepwater rice areas in Southeast Asia. Its recent ecological success in the wider region is based primarily on introgression of photoperiod insensitive trait from modern rice varieties. This has resulted in the removal of reproductive control by daylength in weedy rice, which broadens its adaptive capacity and increases hybridization opportunities. The paddy field environment favorable to weedy rice is created by modern crop management practices—from land preparation to direct seeding, combine harvesting, and chemical weed control. The arrival of modern rice technology at the end of the twentieth century has brought economic and social benefits to Southeast Asia, and also an unintended harm to rice production with invasive weedy rice. Weedy rice control should benefit from a comprehensive understanding of the mechanisms driving its sudden invasiveness and spread.

Agriculture is a key contributor to gaseous emissions causing climate change, the degradation of water quality, and biodiversity loss. The extant climate change crisis is driving a focus on mitigating agricultural gaseous emissions, but wider policy objectives, beyond net zero, mean that evidence on the potential co-benefits or trade-offs associated with on-farm intervention is warranted. For novelty, aggregated data on farm structure and spatial distribution for different farm types were integrated with high-resolution data on the natural environment to generate representative model farms. Accounting for existing mitigation effects, the Catchment Systems Model was then used to quantify global warming potential, emissions to water, and other outcomes for water management catchments across England under both business-as-usual and a maximum technically feasible mitigation potential scenario. Mapped spatial patterns were overlain with the distributions of areas experiencing poor water quality and biodiversity loss to examine potential co-benefits. The median business-as-usual GWP20 and GWP100, excluding embedded emissions, were estimated to be 4606 kg CO₂ eq. ha⁻¹ (inter-quartile range 4240 kg CO₂ eq. ha−¹) and 2334 kg CO₂ eq. ha⁻¹ (inter-quartile range 1462 kg CO₂ eq. ha⁻¹), respectively. The ratios of business-as-usual GHG emissions to monetized farm production ranged between 0.58 and 8.89 kg CO₂ eq. £⁻¹ for GWP20, compared with 0.53–3.99 kg CO₂ eq. £⁻¹ for GWP100. The maximum mitigation potentials ranged between 17 and 30% for GWP20 and 19-27% for GWP100 with both corresponding medians estimated to be ~24%. Here, we show for the first time that the co-benefits for water quality associated with reductions in phosphorus and sediment loss were both equivalent to around a 34% reduction, relative to business-as-usual, in specific management catchment reporting units where excess water pollutant loads were identified. Several mitigation measures included in the mitigation scenario were also identified as having the potential to deliver co-benefits for terrestrial biodiversity.

Crop cultivar mixtures commonly increase productivity in the short term and stabilize or enhance productivity in the long term. However, these effects can be highly variable, likely due to limited research that has experimentally addressed intraspecific diverse effects over time and simultaneously explored their underlying mechanisms. We explored the effects of cultivar mixtures on the temporal yield stability and crop productivity trends in a 7-year (2016–2022) field experiment with maize in Northwest China. Further, we investigated the mechanisms underlying the enhanced productivity and temporal stability, which may be attributed to complementarity effects and asynchrony derived from functional trait dissimilarity among the maize cultivars in the mixtures. Across all cultivar mixtures over the 7 years, grain yield and aboveground biomass increased by 5.6% and 3.6%, respectively, compared to the monocultures. To investigate changes in temporal yield stability over the 7 years, we calculated stability using 3-year rolling windows. Our results showed that temporal yield stability in cultivar mixtures increased during the later years (2019–2022), compared to the monocultures. Over the 7 years, grain yield and aboveground biomass outperformed monocultures by 35% and 38%, respectively, compared to the first year. Complementarity effects were strong and increased over time. The mean values of functional traits changed in response to mixtures, leading to plant height and ear height traits correlating positively with complementarity effects, which were correlated with temporal yield stability. Asynchrony, or variation in the responses of cultivars to environmental fluctuations, was negatively correlated with the temporal deviation in yield. These results, for the first time, indicated that large differences in mean trait values among cultivars, or those that express dynamic trait responses to diversity, can increase complementarity effects and asynchrony, producing more productive and stable crops. This increases our understanding of how intraspecific diversity might contribute to sustainable agroecosystems.