Microbial regulation of net N mineralisation is driven by C, N, P content and stoichiometry

Abstract

Soil net nitrogen mineralisation (Nt) is crucial for nitrogen availability and ecosystem productivity. However, the patterns and drivers of Nt remain unclear under different management practices. We examined the biotic and abiotic determinants of Nt, using 11 treatments in Northern China fluvo-aquic soil under wheat-maize rotation. Biotic properties, for example, soil microbial community, were determined based on phospholipid fatty acid (PLFA) together with high-throughput sequencing technologies. Abiotic properties were characterised by the content and stoichiometric ratios of soil nutrients.Animal manure applications (HNM, NM, M, FM) significantly increased the Nt (1.80-3.40 mg kg À1 ) and available phosphorus (Olsen-P) (46.3-199.3 mg kg À1 ), compared with treatments with plant residues (NG, NS) incorporation.Fallow with animal manure (FM) had the highest Gram-negative bacteria (G-, 29.3 nmol g À1 ), arbuscular mycorrhizal fungi (AMF, 4.57 nmol g À1 ) abundance, which was also significantly higher than that of the NG and NS. Structural Equation Modelling revealed that the content of total nutrient, including soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) rather than biotic properties, such as microbial community (λ = À0.26) and enzyme activities (λ = À0.16), had the strongest direct effect on Nt (λ = 0.85). Stoichiometric ratios of C, N, and P controlled Nt indirectly by mediating enzyme activities. Specifically, high Nt was associated with low Dothideomycetes, Tectomicrobia abundance that negatively correlated with SOC, TN, TP, Olsen-P, and BG activity. Random forest model indicated that SOC and Olsen-P contents were top-rated determinants of Nt. Our result indicated that the content and stoichiometric ratios of SOC and N, P directly drive Nt or via microbial ways. Our study highlighted the importance of P to improve Nt: animal manure was thus recommended for nitrogen availability. Highlights• Animal manure significantly enhanced Nt rather than plant residue incorporation • Nt is negatively correlated with the AN:Olsen-P ratio and Dothideomycetes abundance

Short-Term Dynamics of Bacterial Community Structure in Restored Abandoned Agricultural Soils under Semi-Arid Conditions

“…Total and available nutrient contents could have contributed to the change in the bacterial community composition of the restored soils, mainly between t1 and t3 (Table S1b,c). Changes in the bacterial community structure favor the decomposition of organic amendments [16,43], consequently favoring the relationships in mineral nutrients [23]. Therefore, the bacterial communities of the soils together with the new characteristics of the restored soils could have generated notable impacts over time in the soils of our study.…”

“…These were more evident in the soils amended with compost from manure (VC, CM, and SC) after 12 months of restoration (Figure 2a,b). The influence exerted by the stoichiometry of soil nutrient content may have produced changes in the composition and functionality of the soil decomposer bacterial community [16], which could reflect differences in nutrient demand and nutrient availability [44]. The use of composted waste to reclaim degraded soils could not only favor a more efficient soil decomposer community, but could also benefit the presence of genera categorized as plant-growth-promoting rhizobacteria (PGPR) [45].…”

“…The addition of organic amendments benefits the physical, chemical, and biological soil properties [10][11][12][13], favoring the supply of nutrients and improving soil functionality [11,12,14,15]. The organic compounds that make up these composted residues depend on their organic provenance and are directly related to their nutrient content (C, N, and P) [16], causing stoichiometric variations in the C:N:P ratio [17] of the amended soils.…”

“…As a consequence, the behavior of the soil microbiome responds to the availability of nutrients [20], and these changes will alter the C, N, and P cycles affecting the biological and physico-chemical reactions carried out by soil micro-organisms [22]. Consequently, the type of organic matter [21] together with the capacity and efficiency of the micro-organisms in the decomposition of the organic matter provided [16] could have a differential effect on the structure of the soil bacterial community, influencing the proliferation of some taxa versus others better adapted to the applied amendment [18]. Therefore, bacterial succession induced by substrate availability could have possible beneficial effects on the functionality and stability of the agroecosystem [23].…”

Deforestation alters dissolved organic carbon and sulfate dynamics in a mountainous headwater catchment—A wavelet analysis

“…In soils, the stoichiometric ratios of carbon, nitrogen, phosphorus, and occasionally sulfur are often used for indicating substrate quality and climate change and land management (Zhang et al, 2018;Luo et al, 2020;Veldkamp et al, 2020). They also play a vital role in regulating nutrient cycling and geochemistry processes by mediating soil microbial activities (Wang et al, 2022). But relatively little information is available on the relevant stoichiometry of sulfur in stream The WTC analysis between dissolved organic carbon (DOC), total dissolved iron (Fe tot ) and sulfate at the 3 Wüstebach catchment stations (W10, W14, W17).…”