Meta-analysis unveils differential effects of agroforestry on soil properties in different zonobiomes

Abstract

Abstract Aims Current comprehensive meta-analysis study aims to explore how agroforestry practices influence soil quality across different climate zones. Since numerous studies proposed agroforestry as the promising agroecological farming systems over conventional monoculture systems to maintain soil quality and to regenerate disturbed soil to counteract the negative consequences of global extensive agricultural approaches. Methods By employing the comprehensive meta-analysis technique on data from 125 studies conducted in tropical, temperate, and Mediterranean environments, we quantitatively assessed the effects of agroforestry on physical, chemical, and biological soil quality indicators. Results Rates of soil erosion, the most important indication of land degradation, were improved in agroforestry systems compared to monocultures, especially in temperate (-138%) and Mediterranean soils (-40%), due to agroforestry-induced improved soil texture, aggregate stability, and soil water regulation. Soil acidification was decreased in tropical (-128%) and Mediterranean soils (-96%), but increased in temperate soils (+ 104%) due to agroforestry practices. Low temperate soil pH suggests high Ca2+ leaching losses as evidenced by decreased Ca2+ (-68%) and increased Fe2+ (+ 129%) and Al3+ (+ 235%) contents. Agroforestry systems increased organic matter accumulation in temperate (+ 86%) and Mediterranean soils (+ 65%), carbon sequestration in all climatic zones (+ 48%: 33–73%), and respiration rates in temperate (+ 119%) and tropical soils (+ 105%). Soil microbial communities, enzyme activities as well as nutrient cycling and availability were generally enhanced in agroforestry systems compared to monocultures. Conclusions Our results provide compelling evidence that agroforestry practices can contribute substantially to sustainable improvement of global soil quality.