Long-term Organic Fertilization Research Articles

Response of Crop Yield and Productivity Contribution Rate to Long-Term Different Fertilization in Northeast of China.

To reveal the changes in crop yield and contribution rate of black soil productivity under long-term different fertilization conditions in black soil areas and to find the important significance of fertilization for sustainable and stable crop yield, high yield, and improving the contribution rate of black soil nutrients. Based on the long-term experiment of black soil fertility in Harbin, the Ministry of Agriculture and Rural Affairs, under the maize-wheat-soybean rotation system, crop yield, sustainability and stability of yield, the contribution rate of black soil productivity, and natural nutrient supply capacity under 10 fertilization treatments (CK, NP, NK, PK, NPK, M, MNP, MNK, MPK, and MNPK) were analyzed. Results showed that, compared with the treatment of chemical fertilizer, yields of maize, wheat, and soybeans increased under treatment of organic fertilizer combined with chemical fertilizer, among which the yields of maize and wheat changed the most. As the rotation period lengthened, the sustainable yield index (SYI) values of chemical fertilizer treatment and its combination with organic fertilizer treatment gradually decreased. During the rotation period, the SYI value follows: chemical fertilizer combined with organic fertilizer > chemical fertilizer > organic fertilizer. The coefficient of variation (CV) of yield stability showed an overall trend of increasing first and then decreasing, with individual treatments showing a gradual increasing trend (NP and NPK; MNP and MNPK). Under different rotation periods, the overall contribution rate of soil productivity of long-term organic fertilizer combined with chemical fertilizer treatment was higher than that of single chemical fertilizer treatment. With the extension of the rotation period, the contribution rate of soil productivity of NPK treatment was higher and slightly increased, while other treatments showed a downward trend. Although the contribution rate of soil productivity of organic-inorganic fertilizer combined treatment (MNP and MNK) showed a downward trend, it still remained at a high level (97.2% and 95.9%). In addition, the black soil has strong phosphorus and potassium supply capacity; nitrogen was lower than those two elements, with an average natural potassium supply capacity of 94.0-97.1%. Therefore, the combination of organic and inorganic fertilizers is one of the most effective fertilization measures to stabilize crop yield in the black soil region. Nitrogen fertilizer, as a limiting factor for crop growth in the black soil region, should be emphasized in its application.

Influence of continuous fertilization on heavy metals accumulation and microorganism communities in greenhouse soils under 22years of long-term manure organic fertilizer experiment.

This study examined the impact of long-term manure organic fertilizer application (3, 8, 13, 18, and 22years) on soil physicochemical properties, heavy metal (HM) accumulation, and microbial communities. Long-term manure application markedly elevated nutrient levels such as available N, P and K, and organic matter content in surface and soil profile. Total and DTPA-HM content in different vertical profiles increased with the application time. Fertilization increases the ratio of exchangeable fraction of Cd (2%-17%) and Zn (9%-24%). The risk assessment of HMs revealed that Cd posed the highest risk (moderate contamination level), followed by Cu, Zn, Pb, and Cr. Due to soil acidification, the time span exceeding the risk screening values of Cr, Cd, and Pb in agricultural land (GB 15618-2018) decreased 53.1, 41.2 and 411.8years, respectiverly, and for risk intervention values of Cr, Cd, Cu, Pb and Zn, the time reduced to 318.5, 137.0, 71.1, 1029.5 and 19.1years, respectiverly. Furthermore, manure application altered the composition and structure of the bacteria and fungi community. The abundance of Actinobacteria, Firmicutes, and Ascomycota increased, whereas Proteobacteria, Acidobacteria, and Basidiomycota was inhibited. SEM and RDA indicated that microbial communities were primarily influenced by pH, soil nutrients and HMs.

Root exudates regulate soil antibiotic resistance genes via rhizosphere microbes under long-term fertilization.

Organic fertilizer application promotes the prevalence of antibiotic resistance genes (ARGs), yet the factors driving temporal differences in ARG abundance under long-term organic fertilizer application remain unclear. This study investigated the temporal dynamics of ARG diversity and abundance in both bulk and rhizosphere soils over 17years (2003-2019), and explored microbial evolution strategies, ARG hosts succession and the influence of root exudates on ARGs regulation. The results showed that the ARGs abundance in rhizosphere soil was lower than that in bulk soil under long-term fertilization, and ARGs abundance exhibited a decrease and then remained stable in rhizosphere soil over time. There was a strong association between host bacteria and dominant ARGs (p<0.05). Structural equations demonstrated that bacterial community had a most pronounced influence on ARGs (p<0.05), and metabolites exhibited an important mediation effect on bacterial community (p<0.05), thereby impacting ARGs. The metabolome analysis evidenced that significant correlations were found between defensive root exudates and most ARGs abundance (p<0.05), like, luteolin-7-glucoside was negatively correlated with tetA(58). These findings provide deeper insights into the dynamics of soil ARGs under long-term fertilization, and identify critical factors that influence ARGs colonization in soils, providing support for controlling the spread of ARGs in agriculture soils.

Configuration of pore structure and related functions in macroaggregates following long-term organic and inorganic fertilization

Fertilization practices are vital for agricultural productivity and soil health. However, the impact of long-term organic and inorganic fertilization on pore structure and related functions in paddy soil is still under-explored. In this study, macroaggregates approximately 5 mm in diameter were collected from a 20-year long-term experiment with no fertilization (CK), and those treated with chemical fertilizer (NPK), organic fertilizer (RS), and a combination of both (RS+NPK). The pore structure of these macroaggregates was examined using synchrotron radiation-based X-ray tomography, alongside a pore network model and skeleton analysis. The soil functions concerning the pore structure at the aggregate scale were assessed through their physical and topological properties. Results indicated that the pore structure of the macroaggregates responded differently to organic versus inorganic fertilization. Specifically, the application of NPK significantly reduced the connected porosity, accessibility, and network complexity within the macroaggregates, whereas the opposite effects were observed with the RS treatment. Connectivity analysis showed that the critical pores in CK, NPK, and RS+NPK treatments originated from plant roots, while those in the RS treatment were likely formed through the decomposition of rice straw. Compared to CK, the NPK treatment exhibited fewer channels with high hydraulic conductance, indicating impaired transportability of water and nutrients under saturated conditions, while the opposite was true for the RS treatments. Furthermore, skeleton analysis highlighted that the NPK treatment has fewer paths for preferential and capillary flow compared to CK, indicating reduced accessibility of air, water, and nutrients under unsaturated conditions. These findings are essential for understanding the changes in soil functions related to pore structure following organic and inorganic fertilizer applications and for optimizing fertilization strategies to preserve soil structure and health.

Comparative Analysis of Nitrogen Use Efficiency in Boro Rice under Long-term Inorganic and Organic Fertilization Practices

An experiment was conducted during Boro rice in the permanent experimental field of the Department of Soil Science, Bangladesh Agricultural University (BAU), Mymensingh to investigae the long term outcome of manure and fertilizers on the yield and Nitrogen Use Efficiency (NUE) of BRRI dhan29 in floodplain (Subtropical) soil (Aeric Haplaquepts). The experiment was designed in a randomized complete block design with three replications. There were ten treatment combinations viz, control; Nitrogen (N); (Nitrogen Phosphorus) NP; Nitrogen Potassium (NK); Nitrogen Phosphorus Potassium (NPK); Nitrogen Zinc (NZn); Nitrogen Sulphur (NS); Nitrogen Sulphur Zinc (NSZn), Nitrogen Phosphorus Potassium Sulphur Zinc (NPKSZn) and NPK+FYM. The yield contributing characters and yield of BRRI dhan29 significantly increased due to different treatments. Grain and straw yields were highly influenced by the application of nutrients in various combinations. The longest panicle length (25.3 cm), the highest 1000 grain weight (22.7 g), the maximum grain yield (6.29 t ha-1), the highest nitrogen uptake in grain (70.4 kg ha-1) were found for the NPKSZn treatment. Grain yield increased by 24.8%, 85.8%, 40.7%, 68.9%, 29.2%, 33.2%, 107.1%, 28.9% and 78.9% due to N, NP, NK, NPK, NS, NSZn, NPKSZn, NZn and NPK+FYM treatments respectively and the corresponding straw yields attainment by 49.6%, 51.1%, 82.0%, 95.3%, 37.8%, 34.4%, 82.7%, 41.8% and 90.2%. The maximum value of apparent nitrogen use efficiency was obtained with NPKSZn (54.06%) treatment which evidently suggested its resultness for the long term fertilized soil.

Adaptation of rhizobacterial and endophytic communities in Citrus Grandis Exocarpium to long-term organic and chemical fertilization.

Organic fertilizers (OF) are crucial for enhancing soil quality and fostering plant growth, offering a more eco-friendly and enduring solution compared to chemical fertilizers (CF). However, few studies have systematically analyzed the effects of OF/CF on root microbiome of medicinal plants, especially in combination with active ingredients. In this study, we investigated the composition and function of bacteria and fungi in the rhizosphere or within the root of traditional Chinese medicinal plants, Citri Grandis Exocarpium (Huajuhong), which were treated with OF or CF over 1, 3, and 5 years (starting from 2018). Additionally, we conducted metabolome analysis to evaluate the effects of different fertilizers on the medicinal properties of Huajuhong. The results indicated that extended fertilization could enhance the microbial population and function in plant roots. Notably, OF demonstrated a stronger influence on bacteria, whereas CF enhanced the cohesion of fungal networks and the number of fungal functional enzymes, and even potentially reduced the proliferation of harmful rhizosphere pathogens. By adopting distancebased redundancy analysis, we identified the key physicochemical characteristics that significantly influence the distribution of endophytes, particularly in the case of OF. In contrast, CF was found to exert a more pronounced impact on the composition of the rhizosphere microbiome. Although the application of OF resulted in a broader spectrum of compounds in Huajuhong peel, CF proved to be more efficacious in elevating the concentrations of flavonoids and polysaccharides in the fruit. Consequently, the effects of long-term application of OF or CF on medicinal plants is different in many ways. This research provides a guide for OF/CF selection from the perspective of soil microecology and aids us to critically assess and understand the effects of both fertilizers on the soil environment, and promotes sustainable development of organic agriculture.

Long-term organic fertilization increases phosphorus content but reduces its release in soil aggregates

There is currently limited published information on the coupling correlation between phosphorus (P) redistribution and release in soil aggregates. To fulfill this gap, we conducted a 10-year field experiment of soil amended with organic fertilizer to investigate phosphorus transformation and immobilization during the organic fertilization process. Microbial communities, functional genes and enzymes were analyzed to elucidate the multi-mechanisms of the conversion among phosphorus fractions. Phosphorus content in soil aggregates was determined as follows: FeP (34 % ~ 45 %) > Ca-P (16 % ~ 27 %) > Oc-P (15 % ~ 17 %) > Or-P (13 % ~ 19 %) > Al-P (4 % ~ 5 %) ≈ Ex-P (2 % ~ 4 %). Compared to a control with only chemical fertilizer, a 13 % ~ 38 % increase in P availability of experimental treatments mixed with chemical and organic fertilizers was attributed to the mineralization of Or-P, but not to the dissolution of inorganic P. Following organic fertilization, the phnF gene was dominant factor to promote the mineralization of Or-P, because it encodes CP lyases that pyrolyzes the CP bounds in organophosphate esters. Overall, organic fertilization decreased P release risk in soil aggregates, especially for the micro-aggregates that showed a higher capacity to activate non-available P and immobilize endogenous P in farmland soil. These results provide a theoretical guidance for the source control of P pollution in agro-ecosystems.

Unraveling the characteristics of microplastics in agricultural soils upon long-term organic fertilizer application: A comprehensive study using diversity indices

Microplastics negatively impact soil health and productivity. Organic fertilizers constitute significant contributors of microplastics in agricultural soils. Nevertheless, comprehensive data on the diversity of microplastics in long-term fertilized soils remain unavailable. In this study, we assessed the presence of microplastics in soils subjected to application of three different organic fertilizers (pig manure, chicken manure, and sludge composts) over 12 years, and evaluated the potential ecological risks posed by microplastic accumulation. The average microplastic abundance in soil was 368.88 ± 207.97 (range: 90–910) items/kg. Microplastic abundance differed among fertilization treatments, with substantial increases of 16.67%, 71.67%, and 61.43% upon low to high application of the three treatments, respectively. Overall, the microplastics predominantly comprised fibers (70.94%) and fragments (25.25%), of which a substantial proportion constituted light-colored microplastics (transparent and white). The size of microplastics was mainly concentrated in the 1–2 mm range (39.96%), with rayon, polypropylene, polyester, and polyethylene being identified as the major types. The risk assessment indices of the three treatments were 229.38, 257.64, and 175.89, respectively, and were all classified as level 4 (high risk). The microplastic diversity integrated index and principal component analysis revealed that microplastics were uniformly distributed throughout the 0–20 cm soil depth consequent to tillage activity. Together, these findings provide a comprehensive assessment of microplastic pollution in long-term fertilized soils and serve as a scientific basis for reducing microplastic contamination in agricultural soils.

Implementasi Sistem Pertanian Organik di Desa Karangrejo, Kecamatan Gumukmas, Kabupaten Jember

The Mulyo Farmer Group of Karangrejo village are the fostered villages of the University of Jember and have long been food producers, especially rice and corn, with the potential to become one of the providers of organic products according to SNI 6729:2016. Therefore it is essential to evaluate the implementation of gab against the standard requirements of organic farming systems. Some of the activities carried out are Evaluation and increasing understanding of the application of organic farming systems by continuing the practice of making biochar from agricultural waste for long-term organic fertilizer base materials; Focus Group Discussion and ongoing assistance by the Soil Biodiversity and Fertility Research Group UNEJ. The results of the activities show that the community and village officials are thrilled and open to several activities to be carried out. The results of the initial evaluation using the checklist for fulfilling the requirements of SNI 6729:2016 are based on eight variables related to fresh plants and plant products, indicating that there is no program yet to meet the needs of the organic farming system of SNI 6729:2016 or it has not yet been fulfilled. Even though it has not been fulfilled, the potential for implementing it remains open if based on its main potential, namely organic fertilizer sources and water sources (lowlands with relatively shallow groundwater tables). The existence of many livestock and agricultural waste (which is not harvested) available throughout the year can be used as a source of organic fertilizer in maintaining soil fertility or health.

Soil Organic Matter and Amorphous Oxides Determine the Surface Electrochemical Properties of Purple Soil Under Long-Term Inorganic and Organic Fertilization

Soil Organic Matter and Amorphous Oxides Determine the Surface Electrochemical Properties of Purple Soil Under Long-Term Inorganic and Organic Fertilization

Comparative evaluation of 16S rRNA primer pairs in identifying nitrifying guilds in soils under long-term organic fertilization and water management.

Compared with 454 sequencing technology, short-read sequencing (e.g., Illumina) technology generates sequences of high accuracy, but limited length (<500 bp). Such a limitation can prove that studying a target gene using a large amplicon (>500 bp) is challenging. The ammonia monooxygenase subunit A (amoA) gene of ammonia-oxidizing archaea (AOA), which plays a crucial part in the nitrification process, is such a gene. By providing a full overview of the community of a functional microbial guild, 16S ribosomal ribonucleic acid (rRNA) gene sequencing could overcome this problem. However, it remains unclear how 16S rRNA primer selection influences the quantification of relative abundance and the identification of community composition of nitrifiers, especially AOA. In the present study, a comparison was made between the performance of primer pairs 338F-806R, 515F-806R, and 515F-907R to a shotgun metagenome approach. The structure of nitrifier communities subjected to different long-term organic matter amendment and water management protocols was assessed. Overall, we observed higher Chao1 richness diversity of soil total bacteria by using 515F-806R compared to 338F-806R and 515F-907R, while higher Pielou's evenness diversity was observed by using 515F-806R and 515F-907R compared to 338F-806R. The studied primer pairs revealed different performances on the relative abundance of Thaumarchaeota, AOB, and NOB. The Thaumarchaeota 16S rRNA sequence was rarely detected using 338F-806R, while the relative abundances of Thaumarchaeota detected using 515F-806R were higher than those detected by using 515F-907R. AOB showed higher proportions in the 338F-806R and 515F-907R data, than in 515F-806R data. Different primers pairs showed significant change in relative proportion of NOB. Nonetheless, we found consistent patterns of the phylotype distribution of nitrifiers in different treatments. Nitrosopumilales (NP) and Nitrososphaerales (NS) clades were the dominant members of the AOA community in soils subject to controlled irrigation, whereas Ca. Nitrosotaleales (NT) and NS clades dominated the AOA community in soils subject to flooding irrigation. Nitrospira lineage II was the dominant NOB phylotype in all samples. Overall, ideal 16S rRNA primer pairs were identified for the analysis of nitrifier communities. Moreover, NP and NT clades of AOA might have distinct environmental adaptation strategies under different irrigation treatments.

Responses of soil fungal and bacterial communities to long-term organic and inorganic nitrogenous fertilizers in an alpine agriculture

Although nitrogen fertilizer is an important measure to increase grain yield, response of soil microbial community to nitrogen fertilizer is still unclear in alpine regions. Based on a long-term (>10 years) nitrogen fertilizer experiment (control, CF: chemical fertilizer, SM: sheep manure; CS: chemical fertilizer + sheep manure) in an alpine agroecosystem of the Lhasa, Xizang, responses of soil bacteria and fungi communities to nitrogen fertilizer was investigated. The CF treatment reduced fungi operational taxonomic unit (OTU) by 13.08 %, phylogenetic diversity by 11.13 % at 10–20 cm, but increased fungi guild number at 0–10 cm by 17.71 %. The SM treatment reduced fungi OTU at 10–20 cm by 11.82 %. Compared to CF and SM treatments, CS treatment had stronger positive effects on bacterial α-diversity, considering that CS treatment but not CF and SM treatments increased bacterial mean nearest taxon distance, species Shannon and Simpson at 10–20 cm. The CF, SM and CS treatments altered fungal community composition at 0–10 and 10–20 cm, bacterial community composition at 10–20 cm, and bacterial species composition at 0–10 cm. The CF and CS treatments altered bacterial phylogenetic composition at 0–10 cm, and the SM and CS treatments altered bacterial functional composition at 0–10 cm. The decreased magnitude of the relative abundance of symbiotroph fungi caused by CS treatment (90.44 %) was stronger than that (65.14 % and 53.62 %) caused by CF and SM treatments at 10–20 cm. Therefore, the SM and CS treatments had stronger effects on soil bacterial functional composition, but the CF treatment had stronger effects on fungal α-diversity. Compared with single application of organic or inorganic nitrogen fertilizer, mixed application of organic and inorganic nitrogen fertilizer was more beneficial to the maintenance and improvement of soil bacterial diversity, but caused more reduction of soil symbiotic fungi and in turn greater potential risk. These scientific findings observed by this study can provide guidance for fertilizer management and soil fertility improvement.

Combining Organic and Inorganic Fertilization Enhances Soil Enzyme Activity, the Bacterial Community, and Molecular Ecological Network Complexity in Coal Mine Reclamation Areas

Combined organic and inorganic fertilization can improve soil fertility in coal mine reclamation areas. However, the contribution of the bacterial community (especially its occurrence patterns) to soil physicochemical properties and enzyme activity needs further evaluation. The objective of this research was to clarify the bacterial community diversity, composition, and intraspecific interactions in response to combined organic and inorganic fertilizer application in coal mine reclamation areas in the Loess Hilly Region, China. Maize rhizosphere soil samples were collected under four fertilization regimes (CK, no fertilization control; NPK, compound inorganic fertilizer; M, organic fertilizer; and NPKM, combined organic and inorganic fertilization) in a 10-year field experiment in Gujiao city, Shanxi Province. Bacterial communities were characterized using high-throughput sequencing of the 16S rRNA gene V3–V4 region. A cross-treatment Spearman correlation network was constructed to explore the bacterial co-occurrence patterns. Compared with CK, NPK, M, and NPKM decreased the pH by 0.59%, 2.27%, and 0.12%; increased the soil organic carbon by 11.25%, 11.69%, and 27.05%; and significantly decreased the bacterial Shannon diversity by 3.68%, 0.14%, and 3.54%, respectively. Compared with CK, NPKM significantly increased sucrase, urease, and alkaline phosphatase activities (p &lt; 0.05). Critically, oligotrophic Acidobacteria were significantly more abundant in CK than in the other treatments. Gemmatimonadetes were more abundant in NPK and M, and Actinobacteria, Bacteroidota, and Patescibacteria were more abundant in NPKM. In addition, network analysis revealed that the keystone taxa in the different fertilization treatments belonged to different network modules and were significantly correlated with soil nutrient content and enzyme activity. Simultaneously, the Actinobacteria enriched in NPKM formed specific clusters through strong symbiosis, and there were significant positive correlations among sucrase, urease, and alkaline phosphatase. In summary, long-term combined organic and inorganic fertilization improved maize rhizosphere soil fertility by regulating enzyme activity, bacterial community composition, and bacterial species interactions in coal mine reclamation areas in the Loess Hilly Region.

Soil Acidification Can Be Improved under Different Long-Term Fertilization Regimes in a Sweetpotato-Wheat Rotation System.

Soil acidification is a significant form of agricultural soil degradation, which is accelerated by irrational fertilizer application. Sweetpotato and wheat rotation has emerged as an important rotation system and an effective strategy to optimize nutrient cycling and enhance soil fertility in hilly areas, which is also a good option to improve soil acidification and raise soil quality. Studying the effects of different fertilization regimes on soil acidification provides crucial data for managing it effectively. An eight-year field experiment explored seven fertilizer treatments: without fertilization (CK), phosphorus (P) and potassium (K) fertilization (PK), nitrogen (N) and K fertilization (NK), NP fertilization (NP), NP with K chloride fertilization (NPK1), NP with K sulfate fertilization (NPK2), and NPK combined with organic fertilization (NPKM). This study focused on the soil acidity, buffering capacity, and related indicators. After eight years of continuous fertilization in the sweetpotato-wheat rotation, all the treatments accelerated the soil acidification. Notably, N fertilization reduced the soil pH by 1.30-1.84, whereas N-deficient soil showed minimal change. Organic fertilizer addition resulted in the slowest pH reduction among the N treatments. Both N-deficient (PK) and organic fertilizer addition (NPKM) significantly increased the soil cation exchange capacity (CEC) by 8.83% and 6.55%, respectively, compared to CK. Similar trends were observed for the soil-buffering capacity (pHBC). NPK2 increased the soil K+ content more effectively than NPK1. NPKM reduced the sodium and magnesium content compared to CK, with the highest magnesium content among the treatments at 1.60 cmol·kg-1. Regression tree analysis identified the N input and soil magnesium and calcium content as the primary factors influencing the pHBC changes. Structural equation modeling showed that the soil pH is mainly influenced by the soil ammonium N content and pHBC, with coefficients of -0.28 and 0.29, respectively. Changes in the soil pH in the sweetpotato-wheat rotation were primarily associated with the pHBC and N input, where the CEC content emerged as the main factor, modulated by magnesium and calcium. Long-term organic fertilization enhances the soil pHBC and CEC, slowing the magnesium reduction and mitigating soil acidification in agricultural settings.

Effects of Long-Term Organic Fertilizer Application on Tea Plantation Soil of Its Physical and Chemical Properties and Microbial Communities

Effects of Long-Term Organic Fertilizer Application on Tea Plantation Soil of Its Physical and Chemical Properties and Microbial Communities

Mitigating soil degradation in continuous cropping banana fields through long-term organic fertilization: Insights from soil acidification, ammonia oxidation, and microbial communities

Exploring the potential of organic fertilizers as a mitigating strategy against the negative consequences induced by prolonged use of inorganic fertilizers in high-intensity banana cultivation is critically essential. Ammonia-oxidizer are closely linked to soil acidification, and how they respond to the long term fertilized banana field soil still poorly understood. In this study, soil samples from long-term inorganic (CF), and inorganically plus organically fertilized banana fields (OF) (from 2010 to 2019) were used to investigate the soil acid buffer capacity (pHBC), the potential nitrification rate (PNR), and the community structure of bacteria, fungi, ammonia-oxidizing archaea (AOA), and bacteria (AOB). Compared to the natural soil (CK, unplanted, and unfertilized), the pH and pHBC in the long-term fertilized banana field (both CF and OF) were significantly reduced. However, the pHBC was 1.3 times higher in soil receiving OF treatment than that in CF treatment. Organic matter (OM) and total nitrogen (TN) were significantly increased in the OF treated soil, which were 1.88 and 1.6 times higher compared to the CF-treated ones. The PNR in banana soil was 3.71–4.85 times higher than in the natural soil. High-throughput sequencing results showed that Candidatus Nitrosospharea SCA1170-like AOA and Nitrosospira spp-like AOB were adapted to long-term fertilization in banana field soil. Potentially pathogenic bacteria, Xanthomonadaceae, were enriched in CF-treated soil compared to CK and OF soils. Opposingly, potentially beneficial Streptomyces and Arthrobacter were enriched in natural soil. Meanwhile, the OF-treated soil demonstrated a greater abundance of beneficial Bacillus and Alicyclobacillus. The study reveals that organic fertilizers ameliorate soil acidification, low organic matter content and microbial diversity compared to inorganic fertilizers for banana cultivation.

Biological Interactions Mediate Soil Functions by Altering Rare Microbial Communities.

Soil microbes, the main driving force of terrestrial biogeochemical cycles, facilitate soil organic matter turnover. However, the influence of the soil fauna on microbial communities remains poorly understood. We investigated soil microbiota dynamics by introducing competition and predation among fauna into two soil ecosystems with different fertilization histories. The interactions significantly affected rare microbial communities including bacteria and fungi. Predation enhanced the abundance of C/N cycle-related genes. Rare microbial communities are important drivers of soil functional gene enrichment. Key rare microbial taxa, including SM1A02, Gammaproteobacteria, and HSB_OF53-F07, were identified. Metabolomics analysis suggested that increased functional gene abundance may be due to specific microbial metabolic activity mediated by soil fauna interactions. Predation had a stronger effect on rare microbes, functional genes, and microbial metabolism compared to competition. Long-term organic fertilizer application increased the soil resistance to animal interactions. These findings provide a comprehensive understanding of microbial community dynamics under soil biological interactions, emphasizing the roles of competition and predation among soil fauna in terrestrial ecosystems.

Active microbial population dynamics and life strategies drive the enhanced carbon use efficiency in high-organic matter soils.

Microbial carbon use efficiency (CUE) is a critical parameter that controls carbon storage in soil, but many uncertainties remain concerning adaptations of microbial communities to long-term fertilization that impact CUE. Based on H218O quantitative stable isotope probing coupled with metagenomic sequencing, we disentangled the roles of active microbial population dynamics and life strategies for CUE in soils after a long-term (35 years) mineral or organic fertilization. We found that the soils rich in organic matter supported high microbial CUE, indicating a more efficient microbial biomass formation and a greater carbon sequestration potential. Organic fertilizers supported active microbial communities characterized by high diversity and a relative increase in net growth rate, as well as an anabolic-biased carbon cycling, which likely explains the observed enhanced CUE. Overall, these results highlight the role of population dynamics and life strategies in understanding and predicting microbial CUE and sequestration in soil.IMPORTANCEMicrobial CUE is a major determinant of global soil organic carbon storage. Understanding the microbial processes underlying CUE can help to maintain soil sustainable productivity and mitigate climate change. Our findings indicated that active microbial communities, adapted to long-term organic fertilization, exhibited a relative increase in net growth rate and a preference for anabolic carbon cycling when compared to those subjected to chemical fertilization. These shifts in population dynamics and life strategies led the active microbes to allocate more carbon to biomass production rather than cellular respiration. Consequently, the more fertile soils may harbor a greater microbially mediated carbon sequestration potential. This finding is of great importance for manipulating microorganisms to increase soil C sequestration.

Long-term organic fertilization combined with deep ploughing enhances carbon sequestration in a rainfed sorghum-maize rotation system

Organic fertilization and deep ploughing are expected to contribute to carbon (C) sequestration in arable soils. This hypothesis was evaluated over 11 years of chemical and organic fertilization under conventional tillage (20 cm) and deep ploughing (40 cm) in a rainfed sorghum-maize rotation system on the Loess Plateau. Soil was collected and analysed to determine the soil organic C (SOC) and total nitrogen (TN) contents in the soil profiles (0–60 cm) or in the macroaggregates, microaggregates and silt and clay fractions (0–20 cm only). The SOC and TN stocks at the 0–60 cm depth displayed a net decrease in the unfertilized control, a marginal increase with chemical fertilizer, a significant increase of 23–45 % and 19–42 %, respectively, with organic amendments and a significant increase of 54 % and 48 %, respectively, when combined with deep ploughing. A critical input amount of 2064 kg C ha−1 yr−1 or 162 kg N ha−1 yr−1 was found to be required to maintain the initial SOC or TN stock. The annual N input was positively correlated with the C sequestration efficiency (P < 0.001). This supports the microbial N mining theory. Organic fertilization increased soil aggregation and the specific activity of N-acetyl-glucosaminidase, which was positively correlated with the specific respiration rate in the whole soil profile (P < 0.001) and aggregates (P < 0.001). This appears to support the stoichiometric decomposition theory. However, deep ploughing decreased the specific activity of N-acetyl-glucosaminidase at the 40–60 cm depth compared with conventional tillage. Collectively, long-term organic fertilization combined with deep ploughing enhances SOC sequestration in three ways: directly through the input of exogenous C, indirectly by alleviating microbial N limitations and increasing the amount and stability of subsoil-associated C, and to a lesser extent by improving soil aggregation.

Long-term application of organic fertilizer prompting the dispersal of antibiotic resistance genes and their health risks in the soil plastisphere

Microplastic (MP) pollution is a rapidly growing global environmental concern that has led to the emergence of a new environmental compartment, the plastisphere, which is a hotspot for the accumulation of antibiotic resistance genes (ARGs) and human bacterial pathogens (HBPs). However, studies on the effects of long-term organic fertilizer application on the dispersal of ARGs and virulence factor genes (VFGs) in the plastisphere of farmland soil have been limited. Here, we performed a field culture experiment by burying nylon bags filled with MPs in paddy soil that had been treated with different fertilizers for over 30 years to explore the changes of ARGs and VFGs in soil plastisphere. Our results show that the soil plastisphere amplified the ARG and VFG pollution caused by organic fertilization by 1.5 and 1.4 times, respectively. And it also led to a 2.7-fold increase in the risk of horizontal gene transfer. Meanwhile, the plastisphere tended to promote deterministic process in the community assembly of HBPs, with an increase of 1.4 times. Network analysis found a significant correlation between ARGs, VFGs, and bacteria in plastisphere. Correlation analysis highlight the important role of mobile genetic elements (MGEs) and bacterial communities in shaping the abundance of ARGs and VFGs, respectively. Our findings provide new insights into the health risk associated with the soil plastisphere due ARGs and VFGs derived from organic fertilizers.