Distribution Characteristics of Microbial Residues within Aggregates of Fluvo-Aquic Soil under Biochar Application

Abstract

The use of biochar as a soil amendment has substantial potential to enhance soil quality and carbon sequestration. However, the responses to the addition of biochar based on soil microbial residues are not well understood, particularly at the aggregate level. Herein, a two-year field experiment investigated the characteristics of distribution of microbial residues in calcareous fluvo-aquic soil aggregates (SA) in Henan Province, China. Four treatments were established as follows: no fertilizer (CK), chemical fertilizer (NPK), biochar (BC), and biochar combined with chemical fertilizer (NPK + BC). The results showed that the effects of particle size substantially impacted the microbial residues with 2–0.25 mm SA having the largest contents of amino sugars and microbial residual carbon (MRC), followed by >2 mm SA. Compared with the CK, the NPK treatment markedly enhanced the levels of glucosamine (GluN), galactosamine (GalN), muramic acid (MurA), total amino sugar (TAS), and MRC in the 2–0.25 mm SA by 26.69%, 24.0%, 23.62%, 25.11%, and 24.82%, respectively. The NPK + BC treatment significantly increased the contents of GluN, GalN, TAS, and MRC in the bulk soil and 0.25–0.053 mm SA compared with the NPK treatment. Bacterial biomass and the activity of N-acetyl-glucosaminidase in the bulk soil and SA markedly and positively affected the content of carbon in the amino sugars and microbial residues. Overall, the 2–0.25 mm SA were microenvironments with the largest accumulation of soil microbial residues, and the combined application of NPK + BC was more effective at increasing the accumulation of microbial residues in the SA, which provides an ideal fertilization strategy to improve the soil microenvironment and enhance soil quality.

No‐till reduced subsoil organic carbon due to decreased microbial necromass in micro‐aggregates

“…Thus, fungal and bacterial necromass C was notably greater in macro‐aggregates (Figure 1). This result is consistent with previous studies by Ding et al (2015) and Cheng et al (2023). Greater microbial necromass in macro‐aggregates is crucial for the SOC capacity to serve as a dynamic source repository because macro‐aggregates are the most dynamic (Ding et al, 2015).…”

“…Ding et al (2015) andCheng et al (2023). Greater microbial F I G U R E 4 Effects of tillage practices on microbial biomass C (a, b), dissolved organic C (c, d), and permanganate oxidizable C (e, f) in aggregates.…”

Biochar and Microplastics Affect Microbial Necromass Accumulation and CO2 and N2O Emissions from Soil

“…To date, only seven studies have explored the effects of BC on MNC accumulation, − and none have investigated the effects of microplastics. Most of these studies have reported that BC increases the content of amino sugars and MNC .…”

“…The introduction of engineered C materials (e.g., BC and microplastics) inevitably influences the composition and stability of the soil C pools. Typically, a single application of BC increases MNC accumulation by 10–20%, − whereas multiple BC applications over a decade-long time frame have been reported to increase MNC by 21–59% . However, some studies have reported a decrease in amino sugar and MNC contents following BC addition.…”

Biochar for Sustainable Farming and Recultivation

“…The Special Issue consists of four subjects centered around "Biochar for Sustainable Farming and Recultivation". These subjects are: (1) the research progress of biochar in carbon sequestration and emission reduction [5]; (2) the consequences of biochar application on soil aggregation [6,7]; (3) the influence of biochar addition on the humification process of organic wastes [8]; and (4) the effects of biochar addition on soil organic carbon transformation and composition [9]. This Special Issue covers both theoretical mechanisms and practical applications, including laboratory incubations and field experiments.…”