Soil acidification reduces the effects of short‐term nutrient enrichment on plant and soil biota and their interactions in grasslands

• Published in: Global change biology Vol. 26; no. 8; pp. 4626 - 4637
• Main Authors: Xiao, Hong, Wang, Bing, Lu, Shunbao, Chen, Dima, Wu, Ying, Zhu, Yuhe, Hu, Shuijin, Bai, Yongfei
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.08.2020
• Subjects: acid soils; Acidification; Agronomy; Anthropogenic factors; anthropogenic stressors; biomass; Biota; Central Asia; Community structure; Economics; Ecosystem assessment; Ecosystems; environmental context; Food chains; Food plants; Food webs; global change; Grasslands; interaction of nutrient additions; microbial communities; Microorganisms; Mineral nutrients; multiple trophic levels; Nematoda; Nematodes; Net Primary Productivity; Nitrogen; nitrogen and phosphorus enrichments; Nutrient enrichment; Nutrients; Phosphorus; Plant communities; plant–soil interactions; Primary production; Soil; Soil acidification; soil food webs; Soil microorganisms; soil nematodes; Soil structure; Soils; Trophic levels; Central Asia; soil food webs; interaction of nutrient additions; plant-soil interactions; nitrogen and phosphorus enrichments; environmental context; multiple trophic levels
• DOI: 10.1111/gcb.15167
• ISSN: 1354-1013; 1365-2486

Soil nitrogen (N) and phosphorus (P) contents, and soil acidification have greatly increased in grassland ecosystems due to increased industrial and agricultural activities. As major environmental and economic concerns worldwide, nutrient enrichment and soil acidification can lead to substantial changes in the diversity and structure of plant and soil communities. Although the separate effects of N and P enrichment on soil food webs have been assessed across different ecosystems, the combined effects of N and P enrichment on multiple trophic levels in soil food webs have not been studied in semiarid grasslands experiencing soil acidification. Here we conducted a short‐term N and P enrichment experiment in non‐acidified and acidified soil in a semiarid grassland on the Mongolian Plateau. We found that net primary productivity was not affected by N or P enrichment alone in either non‐acidified or acidified soil, but was increased by combined N and P enrichment in both non‐acidified and acidified soil. Nutrient enrichment decreased the biomass of most microbial groups in non‐acidified soil (the decrease tended to be greatest with combined N and P enrichment) but not in acidified soil, and did not affect most soil nematode variables in non‐acidified or acidified soil. Nutrient enrichment also changed plant and microbial community structure in non‐acidified but not in acidified soil, and had no effect on nematode community structure in non‐acidified or acidified soil. These results indicate that the responses to short‐term nutrient enrichment were weaker for higher trophic groups (nematodes) than for lower trophic groups (microorganisms) and primary producers (plants). The findings increase our understanding of the effects of nutrient enrichment on multiple trophic levels of soil food webs, and highlight that soil acidification, as an anthropogenic stressor, reduced the responses of plants and soil food webs to nutrient enrichment and weakened plant–soil interactions. Although the separate effects of N and P enrichment on soil food webs have been assessed across different ecosystems, the combined effects of N and P enrichment on multiple trophic levels in soil food webs have not been studied in semiarid grasslands experiencing soil acidification. Here we conducted an N and P enrichment experiment in non‐acidified and acidified soil in a semiarid grassland on the Mongolian Plateau. Our results showed that soil acidification, as an anthropogenic stressor, reduced the responses of plants and soil food webs to nutrient enrichment and weakened plant–soil interactions.