Microbial community and network differently reshaped by crushed straw or biochar incorporation and associated with nitrogen fertilizer level

Abstract

Straw returning has been demonstrated as a beneficial approach for the utilization of renewable biomass source, which contributes to reducing environmental pollution and strengthening the sustainability of agriculture. However, information on how microorganisms respond to different straw return modes (SRMs) at varying nitrogen fertilizer levels (NFLs) in the black soil is still limited. The community composition, network pattern, and modular function of bacteria and fungi are investigated under three SRMs, including straw removal (CK), crushed straw incorporation (SD), and biochar incorporation (BC) at three NFLs (0, 144, and 240 kg N ha−1, respectively) mainly using Illumina MiSeq technique based on a long‐term maize field experiment. Results showed that bacterial richness, diversity, and fungal richness decreased with NFL reduction. However, these decreases can be compensated by SD and BC, demonstrating superiority for BC at reduced NFLs. SD and BC differed in their effects on the bacterial and fungal abundances (showing increments only in SD) and fungal Shannon diversity (remaining stable only in BC irrespective of NFLs). Microbial communities were substantially affected by SRMs and interacted with NFLs, which were driven by soil NH4+‐N, available potassium, total nitrogen, and pH. In addition, SD induced a network characterized by its highly complex (average degree 10.259 vs. 3.364) and stable structure (average clustering coefficient 0.503 vs. 0.239), Ascomycota as predominating keystone taxa, and abundant N‐cycling related bacteria, while BC formed a network comprising a superior modular structure (modularity 2.599 vs. 0.912), dominant symbiotic fungi, and soil bulk density as specific shaping factor, indicating that network pattern, keystone taxa, modular function, and determining factors shifted between SD and BC co‐occurrence networks. These results deepen insights into the response divergence of bacteria and fungi to SRMs and NFLs, providing a scientific basis for selecting the suitable strategy for sustainable straw utilization in the black soil area.

Improvement of Active Organic Carbon Distribution and Soil Quality with the Combination of Deep Tillage and No-Tillage Straw Returning Mode

“…Carbon pool activity (CA) = LOC in the sample No − LOC in the soil sample (5) Carbon pool activity index (AI) = CA in the sample CA in the reference soil sample (6) Carbon pool management index (CPMI)= CPI × AI × 100 (7) The SOC and LOC contents determined in this study are used in the calculations according to the method proposed by Blair et al [35]. The soil sample from the RT-N0 treatment in this study is used as the reference soil, and No-LOC is the difference between SOC and LOC contents in the corresponding soil sample.…”

“…The effective utilization of this biomass resource through straw return to the field has significant implications for mitigating global climate change and addressing resource scarcity issues [2][3][4]. The incorporation of straw into the soil can regulate the metabolic activity of soil microorganisms [5,6], and its metabolic products are an important source of soil organic matter, such as enzymes, polysaccharides, and proteins [7]. The increase in this type of soil organic matter creates favorable conditions for improving soil quality and fertility and can potentially replace a portion of chemical fertilizers in the long term [8,9], thereby reducing production costs and increasing crop yields.…”

Effects of Fertilization Practices on the Metabolic Functions of Soil Microbial Communities under Subsurface Irrigation with Stalk Composite Pipe

“…Crop residues represent an abundant and renewable biomass resource [1], with their reintegration into agricultural land recognized as a promising nutrient recycling strategy [2]. Subsurface irrigation with the stalk composite pipe technique (SSI) is a novel fusion of subterranean watering and crop residue return practices [3].…”

“…In light of this, the current investigation utilized Biolog Ecoplate™ to scrutinize how dual fertilization methods and trio nitrogen dosing regimens influence the functionality of soil microbial communities and the decomposition of straw. The study was driven by three key aims: (1) to elucidate the influence of distinct nitrogen doses and fertilization techniques on the functionality of soil microbial communities within the context of SSI, (2) to decode the relationship between straw decay and the functional diversity indexes of soil microbial communities, and (3) to pinpoint fertilization practices that fine-tune stalk composite pipe decomposition and govern its service life. The findings are anticipated to lay a scientific groundwork for developing efficacious fertilization blueprints for SSI systems.…”