Does pH matter for ecosystem multifunctionality? An empirical test in a semi‐arid grassland on the Loess Plateau

Abstract

1. Globally, higher inputs of acid deposition and anthropogenic reactive nitrogen cause lower pH in soils, that is, soil acidification, which may broadly influence both above-and below-ground biota and their habitats. However, we know little about the consequences of soil acidification for a wide range of ecosystem functions and services (i.e. ecosystem multifunctionality).2. Here, we examined the impacts of short-term soil acidification on 19 ecosystem functions relevant to ecosystem primary productivity and the cycling and/or storage of soil carbon (C), nitrogen (N) and phosphorus (P) using a 2-year acid addition field experiment in a semi-arid grassland on the Loess Plateau, China.We further assessed the potential pathways through which plant diversity and soil processes drive ecosystem multifunctionality (hereafter, EMF, EMFproductivity, EMF-C, EMF-N, EMF-P).3. We found that soil acidification suppressed 15 of the 19 individual ecosystem functions. By accounting for other biotic and abiotic confounding variables, we found that soil pH remains to be the dominant one explaining the variation in EMF, EMF-C and EMF-N. The underlying mechanisms of soil pH driving multifunctionality varied substantially among the groups of multifunctionality. Specifically, plant-related variables (i.e. species richness and abundance) exhibited stronger mediating effects on EMF-productivity and EMF-C than did soil properties (i.e. soil K + , Ca 2+ , Mg 2+ and Na + ions) and microbial-related variables (i.e. microbial biomass C and N). 4. Our findings provide empirical evidence that short-term soil acidification could have greater negative effects on ecosystem multifunctionality than expected in the arid and semi-arid areas where alkaline soils are commonly seen. This study also indicates that more attention should be paid to the biological mechanisms mediating multifunctional ecosystems under a global change scenario in the future.

Biodiversity of network modules drives ecosystem functioning in biochar-amended paddy soil

“…This was largely attributed to the biochar addition increasing soil pH, thus hindering soil acidification ( Dong et al, 2022 ; Figure 7 ). Soil acidification decelerated nutrient provisioning, litter decomposition, and element cycling, thereby negatively affecting soil ecosystem multifunctionality ( Eldridge et al, 2020 ; Shen et al, 2021 ; Wei et al, 2022 ). In addition, with its highly porous and loose characteristics, biochar can promote the growth and proliferation of soil microorganisms by offering more room ( Jaafar et al, 2014 , 2015 ; Ye et al, 2017 ).…”

Intermediate soil acidification induces highest nitrous oxide emissions

“…For this study, we randomly chose four replicate field plots of five treatments, 0 (the control, A0), 2.76 (A1), 5.52 (A2), 11.04 (A3), and 16.56 (A4) mol H + m − 2 yr − 1 , to investigate the impact of soil acidification on soil nitrifiers, denitrifiers and denitrification. The acid experiment at the Guyuan site was established in 2016 with 30 plots (2 m × 2 m each) using a randomized block design 80 . It had five levels of acid additions with six replicate blocks separated by 1 m walkways.…”

Soil microbiomes and one health

“…Important microbial groups such as Acidobacteria, Bacteroidetes and Actinobacteria display predictable patterns across pH gradient in soil 130 . A range of recent microbiome studies have shown that soil pH drives, directly and indirectly, the effects of soil microbial communities on plant growth, ecosystem-or soil multifunctionality 132 . For instance, the ability of mycorrhizal fungi to forage for nutrients and deliver them to plants is directly linked to soil pH 52,133 .…”