Soil pH determines microbial utilization strategy for straw-derived hydrophilic and hydrophobic fractions in a Ferralsol

作者：Xiaodong Zheng, Anna Gunina, Yunying Fang, Lukas Van Zwieten, Nanthi Bolan, Xiang Li, Lan Wei, Lianxi Huang, Yufen Huang, Qimei Lin, Hailong Wang, Zhongzhen Liu · 发表于：Carbon Research · 年份：2023 · DOI：10.1007/s44246-023-00075-z · 被引用次数：5 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Soil and Unsaturated Flow

Abstract Lime is commonly used to neutralize acidic soil in practical farmland management. This study aimed to examine the effect of soil pH change by liming in acidic soil on the mineralization and microbial assimilation of 13 C-labelled maize straw-derived hydrophilic and hydrophobic fractions in a 60-d incubation experiment. Our results showed a higher cumulative mineralization of hydrophilic fraction in acidic (34.5%) than neutralized Ferralsol (22.3%), related to lower microbial substrate use efficiency under low soil pH. The cumulative mineralization of hydrophobic fraction was similar between acidic and neutralized Ferralsol. Soil pH affected substrate (hydrophilic and hydrophobic fractions) utilization by actinomycetes and bacteria, but not fungi. The utilization of hydrophilic fraction followed the order: bacteria (57–68%) > actinomycetes (10–19%) > fungi (4.2–5.5%). In contrast, utilization of hydrophobic fraction was the highest for fungi (24–38%), followed by bacteria (21–29%) and actinomycetes (3.2–15%). Actinomycetes showed a greater preference for hydrophilic fraction in neutralized than acidic Ferralsol; bacteria preferred to utilize hydrophilic fraction in both soils, while fungi favored hydrophobic fraction. Also, various substrate uses were found in specific phospholipid fatty acids, which showed that some individual species harbor particular organic C metabolization strategies. In conclusion, soil pH regulates the mineralization of hydrophilic fracti...