Multifunctionality of temperate alley-cropping agroforestry outperforms open cropland and grassland

Abstract

Intensively managed open croplands are highly productive but often have deleterious environmental impacts. Temperate agroforestry potentially improves ecosystem functions, although comprehensive analysis is lacking. Here, we measured primary data on 47 indicators of seven ecosystem functions in croplands and 16 indicators of four ecosystem functions in grasslands to assess how alley-cropping agroforestry performs compared to open cropland and grassland. Carbon sequestration, habitat for soil biological activity, and wind erosion resistance improved for cropland agroforestry (P ≤ 0.03) whereas only carbon sequestration improved for grassland agroforestry (P < 0.01). In cropland agroforestry, soil nutrient cycling, soil greenhouse gas abatement, and water regulation did not improve, due to customary high fertilization rates. Alley-cropping agroforestry increased multifunctionality, compared to open croplands. To ameliorate the environmental benefits of agroforestry, more efficient use of nutrients is required. Financial incentives should focus on conversion of open croplands to alley-cropping agroforestry and incorporate fertilizer management.

Temperate silvopastures provide greater ecosystem services than conventional pasture systems

“…Despite the greater SOC contents, SOC stocks did not differ between systems, a trend that has been recently observed by Veldkamp et al (2023) 3 when comparing grasslands and croplands to agroforestry systems in Germany. Upson et al (2016) 40 argue that SOC stocks in silvopasture topsoil can be affected more by forage than tree inputs; thus, increases in SOC stocks in silvopasture relative to pasture can be lower or not significant compared to other agroforestry systems (e.g., alley cropping) 5 .…”

“…Indeed, lower mean soil C:N ratio in converted pastures (16.5) compared to converted silvopastures (18.4) were linked to increases in soil N, whereas SOC remained unaltered in the 0–30 cm layer 43 . Enhanced nutrient use efficiency through proper fertilization management is key to enhance nutrient cycling and abatement of GHGs in agroforestry systems 3 . Here, the observed reduction in soil C:N ratio can be attributed to C losses through microbial respiration in more warmer and humid conditions compared to other temperate systems, with selective N accumulation after continuous leaf and poultry litter inputs in the silvopasture 10 .…”

“…The capacity of silvopastures to deliver more and, in some cases, enhance ecosystem services, is typically associated with environmental benefits and greater system-wide stability in the face of climate change 3 . Carbon sequestration is a primary regulating service of silvopastures, owing to increased aboveground biomass and the presence of deep-rooted perennial grasses and trees 4 , 5 .…”

“…Consequently, it is estimated that silvopasture systems can sequester 0.55–1.9 Mg ha −1 C per year, and the conversion of degraded and abandoned lands into silvopasture globally has the potential to assimilate 26.6 gigatons of CO 2 equivalent by 2050 6 . Nevertheless, the management of silvopasture systems is complex, and employing proper tree and grazing intensity, the optimum combination of trees and forages, as well as proper nutrient management 3 , is critical to enhance C sequestration and nutrient cycling in silvospastures 7 – 10 .…”

Orientation of tree rows in alley cropping systems matters – The “ShadOT” modelling tool for tree growth and shading effects

“…As a way to address global challenges such as climate change, loss of biodiversity, and environmental degradation, agroforestry is gaining broader acceptance as a potential approach to improve ecosystem services in sustainable intensified cropping systems [31] . When planning and establishing semi-natural habitats e.g.…”