Relationships between soil ecosystem services in temperate annual field crops: A systematic review.

Agricultural soils provide multiple ecosystem services (ES) that can replace chemical inputs to support agricultural production. However, most arable cropping systems are managed with little concern for preserving ecological functions, which could reduce their ability to provide these ES. An increasing number of studies assess ES from agroecosystems, but analysis of multiple ES distinguishing relationships that may exist between them and between these ES and their drivers is lacking. Thus, we performed a systematic literature review of soil-based ES relationships, with a focus on temperate annual field crops. Forty relevant studies out of 870 were selected for the analysis. We created an original ontology of soil-based ES, based on the indicators used to assess them, to which we added soil-based negative impacts and biomass production (defined as a good) to combine the ES approach and the impact approach. We summarized each positive (synergy), negative (trade-off) or non-significant relationship in these studies, which were either quantitative or qualitative. We highlighted key relationships that have never been investigated in the corpus selected, such as relationships between C sequestration and physical soil quality regulation, soil erosion regulation or soil biodiversity. Relationships between biomass production and soil-based ES or impacts were investigated the most and were mainly non-significant. This suggests there are agroecological practices for which maximizing bundles of ES does not always decrease agricultural production. Relationships between soil biodiversity and soil-based ES were exclusively synergistic or non-significant. Summarizing effects of drivers of these relationships revealed that the three pillars of conservation agriculture - rotation diversification (with ley or legumes), soil coverage with cover crops and reduced tillage - and organic fertilization seem promising practices to help provide balanced bundles of ES and potentially reduce negative agronomic impacts. We highlighted potential trade-offs that should be consciously considered when adapting management strategies.