Alley Cropping Mitigates the Impacts of Climate Change on a Wheat Crop in a Mediterranean Environment: A Biophysical Model-Based Assessment

Abstract

Introduction: Climate change (CC) and the increased occurrence of extreme climatic events pose a serious threat to crop yields and their stability worldwide. This study analyzed the CC mitigation potential of an alley cropping system on crop physiological stresses and growth as compared to a monoculture system. Materials and Methods: Growth of winter durum wheat, cultivated alone (agriculture) and in combination with hybrid walnut (agroforestry), was simulated with the Hi-sAFe agroforestry model, as driven by business-as-usual Intergovernmental Panel on Climate Change (IPCC) projections, split into three scenarios, representing Past (1951–1990), Present (1991–2030), and Future (2031–2070) climatic conditions. Crop growth and the occurrence of thermal, nitrogen, and water stresses were analyzed. Results: Cold-related stresses were modest in Past and almost disappeared over time. Heat, drought, and nitrogen stresses increased about twofold from Past to Future, but were reduced by 20–35% in agroforestry, already with medium-sized trees (diameter at breast height (DBH) of about 10–15 cm). Crop yields in agriculture increased from Past to the end of Present and then remained stable. This moderately decreased with tree age in agroforestry (especially in Future). Discussion: The impact of CC on the crop was buffered in agroforestry, especially for the most extreme climatic events. The mitigation of crop microclimate and the increased stability of crop yields highlight the potential of agroforestry as a CC adaptation strategy.

Competition, stress and benefits: Trees and crops in the transition zone of a temperate short rotation alley cropping agroforestry system

“…The temporal differences in the developmental stages of crop and tree are important. For example, the impact on crop yield is small, if crops have reached important developmental stages before trees are fully foliated; this is the case for late leafing trees such as walnut (Reyes et al., 2021). Past research found indications for morphological and/or physiological adaptation strategies of field crops to shade conditions.…”

Nature Based Climate Change Adaptation Measures for Sustainable Crops Production in Ethiopia: Review

“…The Rib watershed, northwestern highland, Ethiopia, will continue to experience climate change with mean annual temperature increasing by 0.24°C per decade and an increase in annual and Kiremt rainfall and a decrease in Belg rainfall [20]. Moreover, simulations of future climate change impacts with the Hi-sAFe agroforestry model indicates that heat, drought, and nitrogen stresses increased about twofold from Past to the future (2031-2070) in the case of Mediterranean Environment [21].…”

“…Agroforestry systems could reduce maize yield losses where climate change threatens maize productivity in Ethiopia [51]. For instance, [21] indicate 20-35% reduced climate change impacts like heat, drought, and nitrogen stresses in an agroforestry systems with mediumsized trees otherwise which would be increased about twofold from past to future. Parkland agroforestry has mutual benefits on providing food security to small-scale farmers and improving the climate change adaptation and mitigation strategies in the case of Tigray Region, Ethiopia [52].…”

Modelling Agroforestry’s Contributions to People—A Review of Available Models

“…This increases the water and nutrient use efficiency of the system [50], but leaves even less water for deep percolation and groundwater recharge. Reducing the radiation input through shading improves the growth condition for the annuals in most circumstances, so that reduced radiation input is compensated for by less stress through high temperatures and slower development [51,52], despite higher night temperatures [53]. A better growing crop, however, consumes more water and nutrients.…”

“…The Hi-sAFe model is potentially able to address all the above-mentioned feedback loops, and has done so with many of them already [51]. What is still missing is the feedback between soil moisture and soil organic matter mineralization/plant N uptake, and the question of whether agroforestry would really reduce N leaching or would just make zoning of N fertilizer demand even more complicated, with undesired effects on N leaching.…”