Effects of the novel pyrimidynyloxybenzoic herbicide ZJ0273 on enzyme activities, microorganisms and its degradation in Chinese soils

Potential of Medicago sativa and Perilla frutescens for overcoming the soil sickness caused by ginseng cultivation

There are serious soil sickness in ginseng cultivation. Crop rotation is an effective agricultural management to improve soil sustainability and reduce soil sickness. To explore an appropriate ginseng rotation system, Medicago sativa (alfalfa) and Perilla frutescens (perilla) were planted on ginseng cultivation soil for 1 year to evaluate the improvement effect of both. Through chemical analysis and high-throughput sequencing technology, we found that after alfalfa and perilla cultivation for one-year, various nutrients and enzyme activities in ginseng cultivation soil were significantly improved. In addition, perilla significantly increased the diversity and richness of soil fungal communities. Cultivation of alfalfa and perilla significantly changed the composition of soil bacterial and fungal communities and significantly reduced the abundance of the potentially pathogenic fungi Ilyonectria. Further pot experiments also showed that the improved soil could significantly increase root activity of ginseng plant after two plants were planted. It should be noted that, unlike alfalfa, perilla decreased soil electrical conductivity, increased soil organic matter, soil urease, and may significantly improve the diversity and richness of soil fungal community. Moreover, in the pot experiment, the root fresh weight of ginseng cultured in perilla treated soil increased significantly. This study highlights that perilla may have better soil improvement effect than alfalfa and it has the potential to be used in the soil improvement of ginseng cultivation.

Beneficial shift of rhizosphere soil nutrients and metabolites under a sugarcane/peanut intercropping system

Intercropping systems have been studied as a sustainable agricultural planting pattern to increase soil quality and crop yields. However, the relationships between metabolites and soil physicochemical properties remain poorly understood under sugarcane/peanut intercropping system. Thus, we determined the rhizosphere soil physicochemical properties, and analyzed rhizosphere soil metabolites and root metabolites by metabolomics method under monoculture and intercropping patterns of sugarcane and peanut. The results showed that pH, the contents of total phosphorus (P), total potassium (K), available nitrogen (N), available phosphorus (P), and available potassium (K) were higher in rhizosphere soil of intercropping peanut than monoculture peanut, and the content of total P was higher in rhizosphere soil of intercropping sugarcane than monoculture sugarcane. Sugarcane/peanut intercropping also significantly increased the activities of acid phosphatase and urease in rhizosphere soil. The metabolomics results showed that 32 metabolites, mainly organic acids and their derivatives (25.00%), nucleotides and their metabolites (18.75%), were detected in root and rhizosphere soil samples. In the MP-S (rhizosphere soil of monoculture peanut) vs. IP-S (rhizosphere soil of intercropping peanut) comparison, 47 differential metabolites (42 upregulated) were screened, including glycerolipids (19.15%), organic acids and their derivatives (17.89%), and amino acids and their metabolites (12.77%). In the MS-S (rhizosphere soil of monoculture sugarcane) vs. IS-S (rhizosphere soil of intercropping sugarcane) comparison, 51 differential metabolites (26 upregulated) were screened, including heterocyclic compounds (15.69%), glycerolipids (11.76%), and organic acids and their derivatives (9.80%). The metabolite species from MP-S, MS-S, IP-S, and IS-S were similar, but some metabolite contents were significantly different, such as adenine, adenosine, maltotriose, thermozeaxanthin-13 and PE-NMe (20:0/24:0). Adenine and adenosine were detected in root and rhizosphere soils, and their levels were increased in the intercropping treatment, which were mainly related to enhanced purine metabolism in root and rhizosphere soils under the sugarcane/peanut intercropping system. Importantly, adenine and adenosine were significantly positively correlated with total P and total K contents, acid phosphatase and urease activities, and pH. This study clarified that the sugarcane/peanut intercropping system could improve soil nutrients and enzymes and was related to purine metabolism.

Effects of planting of two common crops, Allium fistulosum and Brassica napus, on soil properties and microbial communities of ginseng cultivation in northeast China

Background

Long-term cultivation of ginseng can cause severe crop disorders and soil sickness. Crop rotation is an effective agricultural management measure to improve soil sustainability and decrease pathogens. However, the suitable ginseng rotation system and the changes in soil microbial community and soil characteristics under the rotation system need to be further explored.

Methods

To explore suitable ginseng crop rotation systems and improve soil utilization, Allium fistulosum and Brassica napus were planted on ginseng cultivation soil for one year. The effects of the two crops on the chemical properties and enzyme activities of the ginseng cultivation soil were evaluated by chemical analysis. In addition, amplicon sequencing targeting 16 s rDNA genes of bacteria and ITS of fungi has been used to characterize the functional and compositional diversity of microbial communities.

Results

The results elucidated that the levels of available phosphorus (AP) and available potassium (AK) in the soil increased significantly after one year of cultivation for both crops and Allium fistulosum cultivation may also have reduced soil salinity. In addition, the effects of the two crops on the activities of key soil enzymes were different. Catalase (CAT), urease (URE), and acid phosphatase (A-PHO) activities were significantly reduced and sucrase (SUC), and laccase (LAC) activities were significantly increased after Allium fistulosum planting. While A-PHO activity was significantly increased and LAC activity was significantly decreased after Brassica napus planting. Allium fistulosum significantly reduced the abundance of soil fungal communities. The cultivation of Allium fistulosum and Brassica napus significantly altered the composition of soil bacterial and fungal communities, where changes in the abundance of dominant microorganisms, such as Ascomycota, and Mortierellomycota, etc., were closely related to soil chemistry and enzyme activity. Moreover, both significantly reduced the abundance of the pathogenic fungus Ilyonectria.

Conclusions

Our study clarified the effects of Allium fistulosum and Brassica napus on the microbial community and physicochemical properties of ginseng cultivated soil and provides a basis for the sustainable application of ginseng cultivation soil and the development of ginseng crop rotation systems.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02592-0.

Compositional Shifts in Microbial Diversity under Traditional Banana Cropping Systems of Sub-Saharan Africa

Simple Summary

In soil, the connection between microbial diversity and plant health is vital in terms of achieving the food security. Here, we suggested the study on soil microbial diversity in diverse cropping systems of banana adopted and followed by small holder farmers over the years. We tracked down the bacterial and fungal diversity in mono cropping and intercropping systems using advanced molecular techniques. Our outcomes likewise uncovered that the impact of cropping systems on bacterial and fungal increments in plant roots and rhizosphere soil. Hence, safeguarding of soil microbial diversity is profoundly significant taking into consideration of the contributions for plant buildups and rhizodeposits into the soil.

Abstract

Improvements in the crop productivity, soil health, and sustainable intensification should be premised on the better understanding of interactions between the cropping systems and soil microbial diversity. In this study, we assessed variations in the microbial communities across the traditional banana-based cropping systems of contrasting monocrop vigor (vigorous or V vs. non-vigorous or NV) and the cropping system (monocrop or MC vs. intercropped or IC) using 16S rDNA (V3–V4) and ITS2 amplicon deep sequencing via Illumina platform. Sequencing results of the bacterial and fungal communities showed high variability among MC and V cropping systems. The abundances of Proteobacteria, Firmicutes, and Actinobacteria were significantly higher in NV (non-vigorous) and V (vigorous) cropping systems; and the abundances of Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes in the MC (monocropping) than IC (intercropping). There were high relative abundances of Pseudomonas (6.1–37.43%), Bacillus (4.5–20.4%), Rhizobium (1.4–6.5%), and Devosia (1.5–6.7%) in the cropping systems. The dominant family of fungal class Incertae_sedis was Mortierellales, which accounted for 8.79–41.12% of total taxa. This result indicated that the cropping systems are vital for supporting the dynamic microbial diversity specifically beneficial for bacterial communities that helps in promoting synergistic plant-soil interactions and total productivity under resource poor conditions of smallholder farmers in sub-Saharan Africa (SSA).

Rhizosphere Microbial Community Diversity and Function Analysis of Cut Chrysanthemum During Continuous Monocropping

As an ornamental flower crop, the long-term continuous monocropping of cut chrysanthemum causes frequent occurrence of diseases, seriously affecting the quality of cut chrysanthemum. The rhizosphere microbial community plays an important role in maintaining the healthy growth of plants, whereas the composition and dynamics of rhizosphere microbial community under continuous monocropping of cut chrysanthemum have not been fully revealed. In this study, the Illumina MiSeq high-throughput sequencing platform was used to monitor the dynamic changes of rhizosphere microbial communities in four varieties of cut chrysanthemum during 0–3 years of monocropping, and the soil physicochemical properties were also determined. Results showed that continuous monocropping significantly increased the fungal community richness and altered the profiles of the bacterial and fungal communities, leading to variation of community beta-diversity. With the increase of continuous cropping time, biocontrol bacteria decreased, while some plant pathogenic fungi were enriched in the rhizosphere of cut chrysanthemum. FAPROTAX-based functional prediction showed that the abundance of gene related to nitrogen and sulfur metabolism and chitin lysis was reduced in the rhizosphere of cut chrysanthemum. FUNGuild-based fungal function prediction showed that plant pathogenic fungal taxa were increasing in the rhizosphere of cut chrysanthemum, mainly Acremonium, Plectosphaerellaceae, Fusarium, and Cladosporium. Continuous cropping also reduced the content of ammonium nitrogen and increased soil salinity, resulting in deterioration of soil physical and chemical properties, which, together with the transformation of rhizosphere microbial community, became part of the reasons for the continuous cropping obstacle of cut chrysanthemum.

Effects of the novel HPPD-inhibitor herbicide QYM201 on enzyme activity and microorganisms, and its degradation in soil

QYM201 is a 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibiting herbicide recently registered in China for controlling grass and broadleaf weeds in wheat. It is a novel herbicide, and its potential harm to soil ecosystems has not yet been reported. This study investigates the influence of QYM201 on soil enzyme activity and microorganism quantities in two different soils at concentrations of 0.1, 1, and 5 mg kg^-1 soil. Results indicate that QYM201 initially inhibited soil protease, urease, and sucrase activity and this effect increased with concentration. During the later stages of incubation, inhibitory effects gradually weakened and by the end of the experiment (45 days), enzyme activity was restored to control levels. Catalase activity was stimulated by QYM201, with significant differences observed between the QYM201-treated groups and the control at the onset of exposure. This stimulation effect decreased during the later stages of the experiment. However, catalase activity was still significantly higher at the end of the experiment compared to the control. The effects of QYM201 on soil microorganisms differed. Initially, bacteria and actinomycetes quantities were decreased by QYM201 (10 days). As the incubation progressed, microorganism quantities in the lower concentration groups (0.1 and 1 mg kg^-1 soil) were restored to control levels, while those of the high concentration group (5 mg kg^-1 soil) did not fully recover. QYM201 did not significantly impact the quantity of fungi. The half-life and degradation rate constant (k) of QYM201 for the two studied soil types were 23.1 days and 16.1 days, and 0.030 and 0.043 day^-1, respectively.

Comparative analysis of rhizosphere soil physiochemical characteristics and microbial communities between rusty and healthy ginseng root

Ginseng rusty root (GRR) symptom is one of the primary diseases of ginseng. There has been a problem of ginseng rusty root, leading to a severe decline in the quality of ginseng. To clarify the relationship between root symptoms of ginseng rust and soil, the physical and chemical properties, enzyme activity, community structure and microbial diversity of GRR and healthy ginseng (HG) rhizosphere soil were analyzed and compared. The pH and redox potential (Eh) of GRR soil decreased, and the contents of total phosphorus (TP), available phosphorus (AP), and available potassium (AK) decreased. The activity of catalase and phosphatase and invertase was lower than that of HG groups. Besides, the microbial community of GRR rhizosphere soil changes much, and its abundance and diversity are significantly reduced. The community structure of GRR rhizosphere soil also shows apparent differences, and the samples of the HG group gathered together, and the samples of the GRR group were dispersed. In general, GRR was closely associated with decreases in soil pH and Eh; decreases in TP, AP, and AK; decreases in the activity of several enzymes. Additionally, it is strongly associated with an increase in pathogenic microorganisms such as Ilyonectria and a reduction of beneficial microorganisms such as Tremellomycetes Acidobacteria subgroup 6 and Gemmatimonadetes.

Effects of Sepiolite and Biochar on Enzyme Activity of Soil Contaminated by Cd and Atrazine

The effects of sepiolite and biochar on the enzymatic activities of the soil in Cd- and atrazine-contaminated soils were studied. During the growth of pakchoi, the activities of acid phosphatase, sucrase, acid protease, and cellulase decreased, catalase activity increased, and urease activity decreased first and then increased. At the first harvest, compared with that for the control group, the soil pH after treatment with remediation materials increased from 5.41 to 7.43; the activities of urease, acid protease, and catalase increased by 62.8%, 38.6%, and 86.1%, respectively. And the activities of sucrase and acid phosphatase decreased by 17.3% and 24.7%, respectively. At the second harvest, the activities of acid phosphatase, acid protease, and cellulase continued to increase, but those of sucrase and catalase decreased. The results showed that soil enzyme activity was closely related to the type and addition of remediation materials, as well as the type of the enzyme.

Fomesafen impacts bacterial communities and enzyme activities in the rhizosphere

Fomesafen, a long-lived protoporphyrinogen-oxidase inhibitor, specially developed for post-emergence control of broad-leaf weeds, is used widely in soybean fields in northern China (Dayan and Duke, 2010). The impact of fomesafen on microbial communities in rhizosphere soils, however, is unknown. In this study we examined fomesafen degradation as well as its effects in the rhizosphere of soybean plants grown in a greenhouse. Fomesafen had shorter half-life in rhizosphere soil than previously reported for bulk soil from the same location (87 vs 120 days). The enzyme activity of soil extracts and the microbial community composition of 16S rRNA genes (16S) amplified from soil DNA were also investigated. Although not immediately apparent, both the high (37.5 mg kg-1) and low (18.75 mg kg-1) doses of fomesafen significantly decreased urease and invertase activities in the rhizosphere soil from days 30 and 45 respectively until the end of the experiment (90 days). Analysis of 16S amplicons demonstrated that fomesafen had a dose dependent effect, decreasing alpha diversity and altering beta diversity. Significant phylum level decreases were observed in five of the ten phyla that were most abundant in the control. Proteobacteria was the only phylum whose relative abundance increased in the presence of fomesafen, driven by increases in the genera Methylophilacaea, Dyella, and Sphingomonas. The functional implications of changes in 16S abundance as predicted using PICRUSt suggested that fomesafen enriched for enzymes involved in xenobiotic metabolism and detoxification (cytochrome P450s and glutathione metabolism). Our data suggest that, despite being degraded more rapidly in the rhizosphere than in bulk soil, fomesafen had long-lasting functional impacts on the soil microbial community.

Impact of fomesafen on the soil microbial communities in soybean fields in Northeastern China

Fomesafen, a widely adopted residual herbicide, is used throughout the soybean region of northern China for the spring planting. However, the ecological risks of using fomesafen in soil remain unknown. The aim of this work was to evaluate the impact of fomesafen on the microbial community structure of soil using laboratory and field experiments. Under laboratory conditions, the application of fomesafen at concentrations of 3.75 and 37.5mg/kg decreased the basal respiration (RB) and microbial biomass carbon (MBC). In contrast, treatment with 375mg/kg of fomesafen resulted in a significant decrease in the RB, MBC, abundance of both Gram+ and Gram- bacteria, and fungal biomass. Analysis of variance showed that the treatment accounted for most of the variance (38.3%) observed in the soil microbial communities. Furthermore, the field experiment showed that long-term fomesafen application in continuously cropped soybean fields affected the soil bacterial community composition by increasing the relative average abundance of Proteobacteria and Actinobacteria species and decreasing the abundance of Verrucomicrobia species. In addition, Acidobacteria and Chloroflexi species showed a pattern of activation-inhibition. Taken together, our results suggest that the application of fomesafen can affect the community structure of soil bacteria in the spring planting soybean region of northern China.

Dissipation of S-metolachlor in plant and soil and effect on enzymatic activities

The present study aimed at evaluating the dissipation of S-metolachlor (S-MET) at three doses in maize growing on diverse physico-chemical properties of soil. The effect of herbicide on dehydrogenase (DHA) and acid phosphatase (ACP) activity was estimated. A modified QuEChERS method using LC-MS/MS has been developed. The limit of quantification (0.001 mg kg^-1) and detection (0.0005 mg kg^-1) were very low for soil and maize samples. The mean recoveries and RSDs for the six spiked levels (0.001-0.5 mg kg^-1) were 91.3 and 5.8%. The biggest differences in concentration of S-MET in maize were observed between the 28th and 63rd days. The dissipation of S-MET in the alkaline soil was the slowest between the 2nd and 7th days, and in the acidic soil between the 5th and 11th days. DT₅₀ of S-MET calculated according to the first-order kinetics model was 11.1-14.7 days (soil) and 9.6-13.9 days (maize). The enzymatic activity of soil was higher in the acidic environment. One observed the significant positive correlation of ACP with pH of soil and contents of potassium and magnesium and negative with contents of phosphorus and organic carbon. The results indicated that at harvest time, the residues of S-MET in maize were well below the safety limit for maize. The findings of this study will foster the research on main parameters influencing the dissipation in maize ecosystems.

Effects of the novel cis-nitromethylene neonicotinoid insecticide Paichongding on enzyme activities and microorganisms in yellow loam and Huangshi soils

Soil enzyme activity and microbial population play important roles in maintaining soil fertility and ensure crop yield. Paichongding (IPP) is a novel cis-nitromethylene neonicotinoid insecticide, which was recently developed in China. In this study, in order to better understand IPP ecological toxicity, the impact of IPP on soil enzyme activity and microbial population in soils was investigated. The results showed that, urease activity was inhibited by IPP before 75 days incubation, after that this inhibiting effect gradually weakened. IPP had different stimulating effects on the activities of dehydrogenase, protease, and catalase. They were consistently stimulated from the initial time in soils. The results of microbial population indicated that the number of bacteria increased after IPP application compared with the control, fungal number increased before 45 days incubation and then decreased. While actinomycete number decreased during degradation period. DT50 (half-life value), k (degradation rate constant) of IPP in S1 (yellow loam soil), and S2 (Huangshi soil) were found 90 days and 173 days, 0.0077 day(-1), and 0.0040 day(-1), respectively.

Impact of the novel neonicotinoid insecticide Paichongding on bacterial communities in yellow loam and Huangshi soils

Insecticides are widely sprayed in modern agriculture for ensuring the crop yield, which could also lead to contamination and insecticide residue in soils. Paichongding (IPP) is a novel neonicotinoid insecticide and was developed recently in China. Soil bacterial community, diversity, and community composition vary widely depending on environmental factors. As for now, little is known about bacterial species thriving, bacterial community diversity, and structure in IPP-spraying soils. In present study, IPP degradation in yellow loam and Huangshi soils was investigated, and bacterial communities and diversity were examined in soil without IPP spray and with IPP spray through pyrosequencing of 16S ribosomal RNA (rRNA) gene amplicons. The degradation ratio of IPP at 60 days after treatment (DAT) reached 51.22 and 34.01 % in yellow loam and Huangshi soil, respectively. A higher richness of operational taxonomic units (OTUs) was found in yellow loam soil (867 OTUs) and Huangshi soil (762 OTUs) without IPP spray while OUTs were relatively low in IPP-spraying soils. The community composition also differed both in phyla and genus level between these two environmental conditions. Proteobacteria, Firmicutes, Planctomycetes, Chloroflexi, Armatimonadetes, and Chlorobi were stimulated to increase after IPP application, while IPP inhibited the phyla of Bacteroidetes, Actinobacteria, and Acidobacteria.