Bio–tillage can continuously regulate the soil environment through plant roots and rhizosphere biological activities and is considered a low disturbance tillage practice that can alleviate soil compaction. However, long term chemical fertilization alone may limit rhizosphere carbon supply and weaken root–microbe interactions. Whether conservation management can coordinate root adaptation and arbuscular mycorrhizal fungal (AMF) responses to ameliorate the compacted soil environment and improve crop growth remains unclear. This study compared five treatments: chemical fertilizer alone (CN), straw return (SR), organic manure application (OM), straw return combined with organic manure application (SROM), and green manure intercropping (GM). SROM and GM showed the most pronounced soil amelioration effects. Compared with CN, SROM enhanced root tensile strength and elongation at break, increased the relative abundances of Glomus and Claroideoglomus and the accumulation of easily extractable and total glomalin–related soil protein (EE–GRSP and T–GRSP), reduced soil bulk density (BD) by 10.68% and 6.57% in the 0–20 and 20–40 cm soil layers, respectively, and increased MWD and GMD by 78.49–82.08%. The effects of GM were concentrated in the 20–40 cm soil layer, where enhanced soybean root Young’s modulus and complementary interspecific root distribution reduced BD by 7.36% and increased total porosity (TP) by 9.36%. GM also increased AMF root colonization, the relative abundance of Claroideoglomus, and soil nutrient availability. Additionally, SROM generally maintained the highest aboveground dry matter accumulation and exhibited the highest instantaneous growth rate, whereas the current–season growth benefit under GM was relatively limited. These findings highlight the key roles of roots and AMF in soil amelioration and soybean growth and provide a reference for optimizing low disturbance soil management in compacted black soil regions.

Arbuscular mycorrhizal fungi (AMF) are key to facilitating crop nitrogen and phosphorus uptake and soil nutrient cycling. Our previous research has shown that intercropping can enhance AMF diversity. However, the changes of AMF diversity and community structure in rhizospheric soil of intercropped maize at various growth stages under nitrogen fertilizer application remain to be further investigated. Therefore high-throughput sequencing methods were used to analyze the AMF community structure and soil chemical properties of intercropped maize at different growth stages under two nitrogen fertilizer application rates in a multi-year fixed-site field experiment. The results showed that the highest colonization rate of intercropped maize was observed at filling stage and was significantly higher than that of monoculture maize across all growth stages (p < 0.05). With the growth of maize, the diversity of AMF and relative abundance of Glomus increased in the rhizosphere soil of maize showed upward trends and its abundance in intercropped maize increased by 32.45% compared with that of monoculture maize. The Shannon index in NF treatment was significantly lower than that in CN treatment (p < 0.05) at mature stage. The results of network analysis showed that the complexity of the AMF network structure was the highest at filling stage. Moreover, the network complexity of the intercropping in NF treatment become even higher. Mantel analysis indicated that at mature stage, Paraglomus and Glomus were extremely significantly correlated with soil pH, SOC and AN. SEM analysis further indicated that nitrogen application was significantly negatively correlated with soil chemical properties, while intercropping directly increased the abundance of AMF structure through interspecific competition. This study suggested that crop diversity under different nitrogen fertilizer application rates mediated AMF-dynamic changes at different growth stages through the changes of soil nutrients due to interspecific interaction.

Arbuscular mycorrhizal fungi (AMF) are increasingly regarded as a biological soil management practice with the potential to regulate soil carbon cycling and improve agroecosystem sustainability. However, their overall contribution to soil organic carbon (SOC) dynamics and allocation under field conditions remains insufficiently quantified. Here, we conducted a global meta-analysis integrating 761 datasets from 45 studies to evaluate the effects of AMF on SOC components, microbial-related carbon, enzyme activities, and crop productivity. Overall, AMF inoculation led to a modest but consistent increase in SOC (5.94%) and a significant improvement in crop yield (14.64%). However, responses varied among carbon fractions, with more pronounced increases observed in labile carbon pools compared to relatively stable components, indicating shifts in carbon allocation rather than uniform carbon accumulation. Subgroup analyses showed that carbon responses were context-dependent. AMF effects varied with inoculation type, fungal genera, plant characteristics, and soil conditions. In particular, mixed inoculants and Rhizophagus showed stronger positive effects, while environmental factors such as soil pH and nitrogen availability modulated the magnitude and direction of responses. Collectively, our results suggest that AMF primarily regulate carbon allocation and transformation pathways in agroecosystems. Optimizing AMF application by matching fungal communities with appropriate crops and soil conditions may enhance soil carbon management and sustainable agricultural productivity.

Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with most crops. They function as promising sustainable agricultural amendments by synergizing with biochar to enhance plant nutrient uptake. However, the effects of AMF and biochar interactions on the yield and nutrient uptake of leguminous crops and the underlying mechanisms remain insufficiently understood. This study employed a two-factor experimental design. Under the baseline conditions of no fertilization (CK), chemical fertilizer application (CF), and biochar-based fertilizer application (BF), treatments with and without AMF inoculation were established, resulting in a total of six experimental treatments. Compared to BF treatment alone, the combined application of AMF and BF (AM + BF) synergistically increased soybean biomass (12.81%) and grain yield (19.45%). This synergistic effect was accompanied by increased plant nitrogen (14.04%) and potassium (21.82%) accumulation. Notably, despite the highest yield, the AM + BF treatment showed a 22.22% reduction in nodule formation rate. This reveals that plant nitrogen acquisition strategies have shifted from relying on biological nitrogen fixation to efficient mycorrhizal pathways, reflecting an inherent optimization of carbon economy. The PLS-SEM model revealed that AMF inoculation altered yield-driving mechanisms: in the absence of AMF, yield could be directly predicted by soil nutrient levels; however, this relationship was disrupted after AMF inoculation. The soil nutrient pathway became non-significant, indicating a transition from a soil chemistry-dependent model to a biologically driven one, where AMF–plant symbiosis became the primary regulator of nutrient uptake. These findings highlight that AMF-BF synergy creates a novel soil–plant feedback mechanism that enhances nutrient acquisition efficiency and optimizes carbon allocation, providing a sustainable approach to boost legume crop yields and reduce environmental footprints.

Dissolved organic matter (DOM) and microbial communities are closely related, DOM provides nutrients to microorganisms, and microbial metabolism can transform DOM. Their interactions affect the material cycle and energy flow of the ecosystem. In this study, surface (0 similar to 15 cm) sediment samples were collected from natural wetlands (river wetland, HL; lake wetland. HP) and artificial wetlands (paddy field, ST; fish pond, YT) in northern cold regions of China, Three dimensional fluorescence spectroscopy and high through put sequencing techniques were employed to reveal the DOM fluorescence spectra and fungal community characteristics of the different types of wetland surface sediment, and their correlation was further analyzed. The results indicated that four kinds of fluorescent components were identified from the surface sediment DOM fluorescence spectrum, including fulvic-like acid component (C1), humic like acid component (C2), and protein-like component [tryptophan like component (C3) and tyrosine like component (C4)], C1 and C2 were significantly positively correlated, while no significant correlations existed among them and the protein-like components. The relative concentration of C1 was higher than that of C2, while the relative concentrations of C3 and C4 were close, The concentration of DOM in YT was relatively higher than that in the other samples. At the same time, there were significant differences in the relative concentration of C2 and protein like components in HL and HP and significant differences in the relative concentrations of C1, C2, and C3 in ST and YT. The dominant species of fungal communities in wetland surface sediment (excluding unclassified groups) were Ascomycota, Basidiomycota, and Rozellomycota. The Chaol richness index and Shannon diversity index of fungal communities in YT were significantly lower, while the Simpson dominance index was significantly higher. The Shannon diversity index in HP was significantly higher than the other samples. C1 and C2 were significantly correlated with fungal community diversity, C2 was significantly correlated with fungal community composition, while protein-like components had no significant correlation with fungal community. C1 and C2 were significantly positively correlated with Ascomycota, C1 was significantly negatively correlated with Chyridiomycota and Monoblepharomycota, and C2 was significantly negatively correlated with Basidiomycota, Rozellomycota, Chytridiomycota, and Monoblepharomycota. Therefore, fungal communities significantly impacted the relative concentration of fluorescent components with relatively large molecular weights of DOM. This study analyzed the DOM fluorescence spectral characteristics and its correlation with fungal communities in the surface sediment of typical wetlands in the cold region of northern China, providing fundamental data for wetland environmental monitoring and evaluation and theoretical references for the rational utilization of wetlands.

Intercropping leguminous and gramineous crops represents a sustainable strategy to optimize nutrient cycling and enhance soil fertility in agricultural production. While most studies on straw returning to field focus on mono4cropping systems, research on mixed decomposition has predominantly been conducted in forest ecosystems, leaving its potential in diverse farmland systems largely unexplored. This study investigated nitrogen utilization rates of maize straw by subsequent crops through 15N-labeled maize straw incorporated into soil and integrated high-throughput sequencing to identify key driving microorganisms. Four kinds of straw incorporated into soil treatments were designed: maize straw alone returning (M), soybean and maize straw mixed 1:1 returning (MS), soybean straw alone returning (S), and control without straw (CN). Following combined straw returning, the average utilization rate of maize straw 15N by maize and soybean increased by 9.40 % and 51.14 %, respectively, compared with maize straw returning to field alone. Under the M and MS treatments, the utilization rate of maize straw 15N by maize increased by 51.23 % and 38.74 %, respectively, under intercropping compared with monocropping. Intercropping significantly enhanced soil microbial diversity, network complexity, and straw degradation potential compared with monocropping. Soil nitrogen content was markedly enhanced and key bacterial genera such as Sphingomonas was enriched, which accelerated straw decomposition in soil, thereby boosting nitrogen utilization efficiency of maize straw in MS treatment. Functional prediction analyses revealed that microbial activities associated with cellulose degradation, aromatic compound metabolism, and nutrient cycling were strengthened. In this study, 15N isotopically labeled maize straw were used to quantitatively analyze the nitrogen utilization of maize straw by subsequent crops. The advantages of soybean/ maize straw combined returning and intercropping were quantitatively evaluated. The findings of this study offer new ideas into enhancing the nutrient utilization efficiency of maize straw through mixing decomposition effects in diversity cropping system.

In agricultural production, it is crucial to increase the availability of phosphorus (P) in cultivated soil to solve the P limitation. Arbuscular mycorrhizal fungi (AMF) have been proven to promote crop nutrient absorption effectively, while biochar can lead to improvements in soil properties. However, the possible synergistic effect of AMF and biochar on P uptake by crops as well as its underlying mechanisms are unclear. In this study, we conducted a pot experiment to explore the effects of biochar and AMF (Glomus etunicatum) on the community of rhizospheric phosphate-solubilizing microorganisms (PSMs) of maize (Zea mays L. Xianyu-335) using metagenomic methods. The experiment used 0 mg P2O5 g·kg−1 soil (P0) and 30 mg P2O5 g·kg−1 soil (P30) application rates. Each P application rate included 0 (NC), 20 g·kg−1 biochar (BC) addition, inoculation AMF, and without AMF treatments (NM) for a total of eight treatments. During the experiment, both the P uptake and the biomass of maize were measured. The study found that the combination of AMF and biochar significantly increased the mycorrhizal colonization rate of maize roots, regardless of P application level. It was observed that the P uptake by maize was significantly increased when exposed to a combination of AMF and biochar. The increase in P uptake in P0 treatments was 67% higher than the sum of the effects of biochar and AMF inoculation alone. The increase was only 35% higher in P30 treatments, demonstrating a substantially higher interactive effect under P0 than under P30 conditions. The AM-BC treatments significantly increased the abundance of Streptomyces, Bacillus, and Pseudomonas, genera that are known to contain PSMs. In addition, the abundance of genes related to P-cycling (gcd, phoD, and ugpQ) in PSMs increased significantly by 1.5–1.8 times in AM-BC treatments compared with NM-BC and AM-NC treatments under P0 conditions. This increase was significantly and positively correlated with the P uptake. Overall, the results suggest that biochar can help AMF colonize the roots, increasing the functional roles of PSMs in the rhizosphere, which in turn promotes P uptake and biomass in maize. This study provides a new way to improve P-use efficiency and reduce the need for P-fertilizer application in agricultural production.

The carbon-nitrogen ratio (C/N ratio) of straw significantly influences its mineralization and nutrient release when returned to the soil. This study utilized indoor culture and outdoor pot experiments to investigate the impact of varying straw ratios on straw mineralization, soil property dynamics, soil microbial communities, soil enzyme activities, and maize growth. Design of treatments included: (1) maize straw return (M), (2) soybean straw return (S), (3) 1:1 ratio of maize straw and soybean straw return (MS), (4) 2:1 ratio of maize straw to soybean straw return (2MS), (5) maize straw return combined with nitrogen fertilizer (MF) and (6) no straw return (NS). Compared with M treatment, MS and MF treatment enhanced the straw mineralization rate and nutrient release, thus increasing the biomass of succeeding maize. The MS treatment increased the relative abundance of Chloroflexi, Acidobacteriota, and Proteobacteria by 15.54%, 5.36%, and 14.29%, respectively, compared to the M treatment. Straw return treatments significantly decreased the prevalence of the pathogenic fungus Fusariumcompared to the NS approach. Correlation analyses indicated a positive association between soil chemical properties and the presence of Proteobacteria, Firmicutes, Bdellovibrionota, and Nitrospirota. Conversely, these factors showed a negative correlation with Actinobacteriota, Gemmatimonadota, Funneliformis, Trichoderma, and Fusarium. These changes in microbial communities are beneficial for straw degradation and nutrient release. In summary, the combined addition of soybean straw and maize straw in a 1:1 ratio optimizes the microbial community, enhances soil nutrient cycling, improves soil fertility, and positively affects corn biomass and nutrient uptake.

Dissolved organic matter (DOM) is the most active component in soil organic matter, affecting heavy metal's migration and transformation. Studying their correlation is of great value for environmental monitoring and pollution assessment. In this study, the topsoil (0 similar to 30 cm) was collected from the typical coniferous and broad-leaved mixed forest in Heilongjiang Province Maolan'gou National Nature Reserve, located in Xiaoxing'anling, China, and three-dimensional fluorescence spectroscopy- parallel factor analysis method was used to reveal the characteristics of forest soil DOM fluorescence spectra, and further to analyze the correlation between DOM fluorescence component and heavy metal content. The results showed that the forest soil DOM fluorescence index ranged from 1.468 to 1.635, with an average value of 1.531, indicating the DOM source had both autogenic and exogenous characteristics. The biological index ranged from 0.563 to 0.646, with an average value of 0.603, indicating a low contribution rate of recent autogenic source; The humification index ranged from 4.607 to 8.993, with an average value of 6.491, indicating a low degree of humification. Threetypes of fivekinds of fluorescent components were identified from the forest soil DOM fluorescence spectrum, including humus-likesubstances [ultraviolet fulvic acid-like component (C1) and visible fulvic acid-like component (C2)], humic acid-like substance (humic acid component, C3), and proteinlike substance [tryptophanlike component(C4) and tyrosinelike component (C5)]. Humus-like substances accounted for the largest proportion of total components (60.12%), significantly higher than humic acid-like and protein-like substances, while humic acid-like substances accounted for the smallest proportion (11.25%) of total components. C1, C2, and C3 had a significant positive correlation, while C5 was significantly negatively correlated with the other four fluorescent components. There was a significant correlation between the fivekinds of fluorescent components and the fluorescence index, respectively, with only C5 showing a positive correlation with the fluorescence index.The forest soil heavy metal contentswere significant differences in the spatial distribution, with significant positive correlations between As and Cr, Cu and Zn, Ni and Zn, Hg and Pb, and significant negative correlations between Hg and Cu, Ni and Zn, Cr, and Pb, respectively.The correlationsamong the three types of fluorescent substances, Cr and Pb, were not significant, but all fluorescent substances had a significant correlation with Zn. Moreover, there was a significant correlation between humus-like substances and Cu and Hg; humic acid-like substances and Cu, Hg, and Ni; protein-like substances and Ni, respectively.The results of this study provide basic data for monitoring the forest soil environment of Maolan'gou National Nature Reserve and provide references for the assessment of heavy metal pollution in the soil of typical coniferous and broad-leaved mixed forests in Xiaoxing'anling.

Nitrogen (N) is the primary element that limits crop growth, and improving the nitrogen uptake in crops is a key challenge in sustainable agricultural production. Arbuscular mycorrhizal fungi (AMF), as important symbiotic microbes associated with most plants, can facilitate nitrogen uptake by plants and reduce greenhouse gas emissions, meaning they can play an important role in the development of sustainable agriculture. However, the effects of biochar application on mediating AMF N absorption are not clear, especially regarding the functional genes related to the N cycle in soil. In this study, we conducted a pot experiment with two P application rates (−P and +P) to study the effects of biochar and AMF on the community of soil microorganisms and N-cycle genes using metagenomic methods. The N uptake of both the shoots and roots of maize was measured. It was observed that the N uptake in the maize shoots and roots was significantly increased when they were exposed to a combination of AMF and biochar. Under both the −P and +P application rates, the root weights of the AMF and biochar combined (AMBC) treatments increased significantly by 58.3% and 43.2%, respectively, compared with the control (CN) treatments. Furthermore, there were significant increases in the root lengths, of 78.43% and 53.09%, respectively, as well as increases in the superficial areas of 60.0% and 41.9%, respectively. The combination treatment significantly changed the soil microbe community structure and increased the abundances of Geobacter and Pseudomonas. In addition, the abundances of the N-cycle genes of each process were enhanced. Under the −P condition, the total abundances of the N-cycle genes increased significantly by 1.97–2.19 times in the AMBC treatment compared with the CN treatment. Overall, the results suggest that biochar and AMF can promote plant root growth and lead to changes in the soil microorganism structure, resulting in an increase in the abundances of N-cycle genes which, in turn, increase the N uptake in the shoots and roots of maize. This study provides a biological pathway to improve the efficiency of N utilization in soil and prevent environmental pollution in sustainable agricultural production.

With the intensification of global climate change and environmental stress, research on abiotic and biotic stress resistance in maize is particularly important. High temperatures and drought, low temperatures, heavy metals, salinization, and diseases are widespread stress factors that can reduce maize yields and are a focus of maize-breeding research. Molecular biology provides new opportunities for the study of maize and other plants. This article reviews the physiological and biochemical responses of maize to high temperatures and drought, low temperatures, heavy metals, salinization, and diseases, as well as the molecular mechanisms associated with them. Special attention is given to key transcription factors in signal transduction pathways and their roles in regulating maize stress adaptability. In addition, the application of transcriptomics, genome-wide association studies (GWAS), and QTL technology provides new strategies for the identification of molecular markers and genes for maize-stress-resistance traits. Crop genetic improvements through gene editing technologies such as the CRISPR/Cas system provide a new avenue for the development of new stress-resistant varieties. These studies not only help to understand the molecular basis of maize stress responses but also provide important scientific evidence for improving crop tolerance through molecular biological methods.

Ammonia-oxidizing archaea (AOA) and Ammonia-oxidizing bacteria (AOB) are key microorganisms in the soil nitrogen cycle, but how they change in the intercropping system, affected by interspecific interaction and N application levels, is not clear. A field experiment of soybean/maize intercropping with three nitrogen application levels was designed. Illumina MiSeq sequencing was used to determine AOA and AOB diversity and communities in the rhizosphere of intercropped soybean and maize. Nitrogen absorption of maize grain has increased by 21.09

IntroductionMaize/soybean intercropping is a common cropping practice in Chinese agriculture, known to boost crop yield and enhance soil fertility. However, the role of below-ground interactions, particularly root exudates, in maintaining intercropping advantages in soybean/maize intercropping systems remains unclear.MethodsThis study aimed to investigate the differences in root exudates between intercropping and monocropping systems through two pot experiments using metabolomics methods. Multiple omics analyses were conducted to explore correlations between differential metabolites and the community of Arbuscular Mycorrhizal Fungi (AMF), shedding light on the mechanisms underlying the dominance of intercropping from the perspective of root exudates-soil microorganism interactions.Results and discussionThe study revealed that intercropping significantly increased the types and contents of root exudates, lowered soil pH, increased the availability of nutrients like available nitrogen (AN) and available phosphorus (AP), and enhanced AMF colonization, resulting in improving the community composition of AMF. Besides, root exudates in intercropping systems differed significantly from those in monocropping, with 41 and 39 differential metabolites identified in the root exudates of soybean/maize, predominantly amino acids and organic acids. The total amount of amino acids in the root exudates of soybean intercropping was 3.61 times higher than in monocropping. Additionally, the addition of root exudates significantly improved the growth of soybean/maize and AMF colonization, with the mycorrhizal colonization rate in intercropping increased by 105.99% and 111.18% compared to monocropping, respectively. The identified metabolic pathways associated with root exudates were closely linked to plant growth, soil fertility improvement, and the formation of AMF. Correlation analysis revealed a significant relationship (P < 0.05) between certain metabolites such as tartaric acid, oxalic acid, malic acid, aspartic acid, alanine, and the AMF community. Notably, the photosynthetic carbon fixation pathway involving aspartic acid showed a strong association with the function of Glomus_f_Glomerace, the dominant genus of AMF. A combined analysis of metabolomics and high throughput sequencing revealed that the root exudates of soybean/maize intercropping have direct or indirect connections with AMF and soil nutrients.ConclusionThis suggests that the increased root exudates of the soybean/maize intercropping system mediate an improvement in AMF community composition, thereby influencing soil fertility and maintaining the advantage of intercropping.

The carbon–nitrogen ratio (C/N ratio) of straw significantly influences its mineralization and nutrient release when returned to the soil. However, little is known about the effects of different mixtures of different types of straw on straw mineralization, dynamic changes of soil properties, soil microbial communities and the growth of later maize. This study was conducted through incubation and pot experiments, with 12 g/kg straw. Design of treatments included: (1) maize straw return (M), (2) soybean straw return (S), (3) 1:1 ratio of maize straw and soybean straw return (MS), (4) 2:1 ratio of maize straw to soybean straw return (2MS), (5) maize straw return combined with nitrogen fertilizer (MF) and (6) no straw return (NS). Compared with M treatment, MS and MF treatment enhanced the straw mineralization rate and nutrient release, thus increasing the biomass of succeeding maize. The MS treatment increased the relative abundance of Chloroflexi, Acidobacteriota, and Proteobacteria by 15.54

Problems: Global demand for food continues to grow as a result of rising incomes and population growth. Meanwhile, the sustainability of food production is affected by climate change and agricultural soil degradation.Objectives: The objective of this study was to evaluate the dynamic changes of maize/soybean yield, yield stability and soil fertility under mono-cropping and intercropping systems with different nitrogen application rates.Methods: The yield stability and sustainability of maize and soybeans were studied from 2017 to 2020 (Northeast Agricultural University, Acheng Experimental Site) according to the changes in crop yield, actual yield loss index, soil fertility over time as well as the differences in coefficient of variation and sustainable yield index under different cropping patterns in the maize/soybean intercropping system. This study established three cropping patterns (maize monoculture, soybean monoculture, and maize/soybean intercropping) with four nitrogen application rates (0/0 kg N ha-1, N0; 180/40 kg N ha-1, N1; 240/80 kg N ha-1, N2; 300/120 kg N ha-1, N3) based on the two-factor split block design. Results: The maize and system yield indicated that intercropping was superior to the corresponding monoculture throughout the four-year experiment. With the extension of planting season, the yield from intercropping with nitrogen treatment (N1, N2 and N3) was higher than that without nitrogen treatment (N0). The yield stability of the intercropping system was also higher than that of the matched monoculture system. The coefficient of variation of the intercropping system was 18.83 % on average, which was lower than that of the matched monoculture system. In four years, the average contribution rate of soil fertility in intercropping treatment was higher than that in monoculture treatment. The structural equation model results suggested that the effect of nitrogen application rate on yield and yield stability was greater than that of cropping pattern. Conclusions: The yield and yield stability of maize/soybean intercropping over time was higher than matched monoculture under different nitrogen application rates due to higher soil fertility contribution in intercropping. Implications: This study provides theoretical evidence for maintaining the sustainability of legume and cereal intercropping and improving food security in the increasingly intensive global cropping systems.

It has been established that maize/soybean intercropping can improve nitrogen use efficiency. However, few studies have addressed how maize/soybean intercropping affects nitrogen-fixing bacterial diversity and N fixation efficiency of intercropped soybean. In this study, nitrogen-fixing bacterial communities, N fixation efficiency, and their relationships with soil properties under three nitrogen fertilization application rates (N0 0 kg/ha, N1 40 kg/ha, N2 80 kg/ha) were explored through field experiments. Nitrogen fixation and nitrogen-fixing bacteria diversity were assessed using 15N natural abundance, Illumina high-throughput sequencing, and nifH (nitrogen fixation) gene copies quantification in the rhizosphere soil of intercropped soybean. The results showed that nitrogen application rates significantly decreased the nitrogen-fixing bacteria diversity, nitrogen fixation efficiency, and nifH gene copies in the rhizosphere soil. Nitrogen fixation efficiency, nodule number, and dry weight of intercropped soybean were highest in the N0 treatment, and nitrogen fixation was the highest in the N1 treatment. The nitrogen-fixing efficiency in N0, N1, and N2 treatments increased by 69%, 59%, and 42% and the nodule number of soybean was 10%, 22%, and 21%, respectively, compared with monocultures. The soybean nitrogen-fixing bacteria diversity in intercropping under N0 and N1 treatments significantly increased compared with monocultures. There was a significant positive correlation between soil nifH gene copies and N fixation efficiency and a negative correlation with soil available nitrogen. Bradyrhizobium abundance in soybean rhizosphere soil decreased significantly with the increase in nitrogen application rates and was significantly correlated with soil AN (available nitrogen) and pH content in the soybean rhizosphere. These results help us to understand the mechanisms by which nitrogen use efficiency was improved, and nitrogen fertilizer could be reduced in legume/Gramineae intercropping, which is important to improve the sustainability of agricultural production.

Understanding the components that shape the rhizosphere community is vital for sustainable disease management. This study evaluated an integrated Verticillium wilt management in eggplant and its influence on the soil microbiome. Six treatments; Self-rooted (control; CLA) and sole grafted (CLB) eggplants, Brassica + Self-rooted plant (BrA), and Brassica + Grafted plants (BrB), with Biochar (10 t/ha) + Brassica + Self-rooted plant (BBrA) and Biochar (10 t/ha) + Brassica + Grafted Plant (BBrB) were used. Soil microbiome was characterized using high-throughput sequencing. The grafted treatments significantly reduced the Verticillium abundance, disease index and improved the yield of eggplant compared with CLA (18.13 t/ha), with BBrB (41.54 t/ha) as the best treatment. Results showed that treatments CLB, BrB, and BBrB stimulated more beneficial microbes, especially Arthrobacter, Bacillus, and Sphingomonas for bacteria; and Mortierella, Tausonia, and Chaetomium for fungi. Treatment BBrB was biomarked by phylum Chloroflexi (o_SBR1031), Acidobacteria, Planctomycetes, and Patescibacteria, but only Chloroflexi (o_SBR1031) was found in BrB, and none of them in CLB and treatment BBrB also contained more biomarkers than other treatments. Similarly, the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis revealed that treatment BBrB contained more genes (17.5%) regulating disease resistance followed by BrB (17.3%) and CLB (16.6%) treatments. In conclusion, grafting with Brassica (biofumigation) under a biochar regime could reduce eggplant Verticillium wilt. This study expands knowledge on how soil microbiota can be enhanced using integrated disease management practices to exploit sustainable food production.

采集黑龙江省种植花生区域的黑土土样,通过湿筛法从花生根际土样中分离纯化出AMF菌孢子,根据形态学特征和分子生物学进行鉴定,获得一株AMF菌,为株幼套球囊霉(Glomus etunicatum),通过Single spore isolating方法完成AMF菌培养繁殖,孢子量350个/g,将获得的纯净孢子接种到以花生为宿主植物的盆钵中,进行扩大繁殖.AMF菌能够促进花生根系伸长生长,提高根系对N,P,K无机盐离子的吸收,而且还具有抗倒伏作用,提高了花生产量,同时提高花生的油脂含量,能使花生中油脂含量提高2.3％～2.7％.

为了快速鉴定二倍体马铃薯种质资源的耐盐性,本研究以17份二倍体马铃薯无性系试管苗为供试材料,测定5个形态指标和8个生理生化指标,并通过主成分分析、隶属函数分析、聚类分析及逐步回归分析对17个无性系进行耐盐性综合评价.结果表明:主成分分析将5个形态指标简化为1个独立的综合指标,将8个生理生化指标简化为4个独立的综合指标;17个无性系被聚类分析为3种耐盐类型,其中耐盐无性系包括A038、A002和A024;利用形态指标建立了耐盐性评价的回归方程;可用于离体快速鉴定二倍体马铃薯耐盐性的指标为芽长、芽干重、根鲜重、根干重、相对含水量、丙二醛含量和脯氨酸含量.本研究可为马铃薯离体耐盐性评价提供参考依据,并为马铃薯耐盐新品种选育提供种质资源.

It is demonstrated that intercropping improves soil fertility, but its effect on deep soil is still unclear. The major objective of this study was to determine the distribution of arbuscular mycorrhizal fungi (AMF) and soil aggregates and their interrelationship across soil depths in intercropping systems. A three-year positioning experiment based on a two-factor experimental design at two N application levels (N0 and N2) and different cropping systems (maize/soybean intercropping and corresponding monocultures) was started in 2017. Soil samples were collected from 0–15 cm and 15–30 cm for analyzing soil aggregates and from 0–15 cm, 15–30 cm, 30–5 cm, and 45–60 cm for determining the AMF composition. It was observed that intercropping improved the macro-aggregate (> 5 mm) content at 0–15 cm and 15–30 cm depths for maize soil and only 0–15 cm depth for soybean soil without N treatment. The application of N decreased the macro-aggregate content in the intercropping soil at 0–15 cm and 15–30 cm depths. Moreover, intercropping significantly improved the AMF diversity of maize and soybean soils across soil depths, while the application of N reduced the AMF diversity of soil across depths. The structural equation modeling analysis indicated that the intercropping system influenced the stability of soil aggregates and promoted the formation of large aggregates by altering soil nutrients and the diversity of AMF. The results further revealed the reasons behind soil fertility improvement by adopting crop diversification.