[Intensive Citrus Cultivation Suppresses Soil Phosphorus Cycling Microbial Activity].

Soil microbes are key drivers in regulating the phosphorus cycle. Elucidating the microbial mineralization process of soil phosphorus-solubilizing bacteria is of great significance for improving nutrient uptake and yield of crops. This study investigated the mechanism by which citrus cultivation affects the soil microbial acquisition strategy for phosphorus by measuring the abundance of the phoD gene, microbial community diversity and structure, and soil phosphorus fractions in the soils of citrus orchards and adjacent natural forests. The results showed that citrus cultivation could lead to a decrease in soil pH and an accumulation of available phosphorus in the soil, with a content as high as 112 mg·kg-1, which was significantly higher than that of natural forests (3.7 mg·kg-1). Citrus cultivation also affected the soil phosphorus fractions, with citrus soil having higher levels of soluble phosphorus (CaCl2-P), citrate-extractable phosphorus (Citrate-P), and mineral-bound phosphorus (HCl-P). The phosphorus fractions of natural forest soils were significantly lower than those of citrus soils, whereas the phoD gene abundance and alkaline phosphatase activity were significantly higher in natural forest soils than in citrus soils. High-throughput sequencing results showed that the Shannon diversity index of phosphate-solubilizing bacteria in citrus soils was 4.61, which was significantly lower than that of natural forests (5.35). The microbial community structure in natural forests was also different from that of citrus soils. In addition, the microbial community composition of phosphate-solubilizing bacteria in citrus soils was also different from that of natural forests, with the relative abundance of Proteobacteria being lower in natural forest soils than in citrus soils. Therefore, citrus cultivation led to a shift of soil microbial acquisition strategy for phosphorus, with external phosphorus addition being the main strategy in citrus soils, whereas microbial mineralization of organic phosphorus was the main strategy in natural forest soils to meet their growth requirements.

The role of large mammalian herbivores in shaping and maintaining soil microbial communities of natural mineral licks: A case study on sika deer at the firebreak adjacent to the Sino-Russian border.

Mineral licks are indispensable habitats to the life history of large mammal herbivores (LMH). Geophagy at licks may provide the necessary minerals for LMH, while LMH may be ecosystem engineers of licks by altering vegetation cover and soil physicochemical properties (SPCP). However, the precise relationship between the LMH and licks remains unclear. To clarify the geophagy function of licks for LMH and their influence on soil at licks, we recorded visitation patterns of sika deer around licks and compared SPCP and microbial communities with the surrounding matrix in a firebreak adjacent to the Sino-Russian border. Our study indirectly supports the "sodium supplementation" hypothesis. Proofs included (1) a significantly higher sodium, iron, and aluminum contents than the matrix, while lower carbon, nitrogen, and moisture contents; (2) significantly higher deer visitation during sodium-demand season (growing season), along with an avoidance of licks with high iron contents, which is toxic when overdose. The microbes at the licks differed from those at the matrix, mainly driven by low soil carbon and nitrogen and altered biogeochemical cycles. The microbial communities of licks are vulnerable because of their unstable state and susceptibility to SPCP changes. Structural equation modeling (SEM) clearly showed a much stronger indirect effect of deer on microbes at licks than at the matrix, especially for bacteria. Multiple deer behaviors at licks, such as grazing, trampling, and excretion, can indirectly shape and stabilize microbes by altering carbon and nitrogen input. Our study is the first to characterize soil microbial communities at mineral licks and demonstrate the processes by which LMH shapes those communities. More studies are required to establish a general relationship between the LMH and licks to promote the conservation of natural licks for wildlife.

Phosphorus fertilization enhances terrestrial carbon cycling in phosphorus-deficient ecosystems.

Anthropogenic phosphorus (P) input into terrestrial soils have been greatly increased, with potential effects on both above- and belowground carbon (C) cycling processes. However, uncertainty about how plant-soil-microbe systems respond to P fertilization makes it difficult to predict the effects of anthropogenic P input on the terrestrial C cycling. In this study, we conducted a global meta-analysis, examining 1183 observations from 142 publications. The findings revealed that P fertilization consistently promoted C cycling variables in plant-soil-microbe systems, resulting in improvements ranging from 7.6% to 49.8% across various ecosystem types. Notably, these positive effects of P fertilization were more pronounced with higher application rates and longer experimental durations. As the background P contents increased, the functions of P fertilization in C cycling variables shifted from positive to negative. Structural equation modeling demonstrated that changes in plant inputs predominantly drove the positive impacts of P fertilization rate and experimental duration, as well as the negative impacts of background P contents on soil respiration and microbial biomass C responses to P fertilization. Our study demonstrated the coherent responses of terrestrial C cycling processes to P fertilization and highlighted the significance of P fertilization boosting C cycling processes in P-deficient ecosystems. We suggested that minimizing the application of P fertilization in P-rich environments would enhance C sequestration and reduce P-induced environmental pollution.

Phosphorus deficiency is the main limiting factor for re-vegetation and soil microorganisms in Mu Us Sandy Land, Northwest China.

Long-term drought induced by low rainfall leads to environmental degradation of land in arid and semi-arid regions. In past decades, re-vegetation of degraded sandy soils to prevent soil erosion has been widely employed, including in Mu Us Sandy Land, which suffers from severe soil erosion. However, it remains unclear how re-vegetation affects soil properties and soil microbes after long restoration periods. In this study, typical plots planting Artemisia ordosica and Salix psammophila were selected to investigate the influence of plant types on soil properties; an area of bare sandy land was used as a control. The results show that re-vegetation increased soil organic carbon (C), total nitrogen (N), soil microbial carbon, microbial nitrogen and soil organic acid, while decreasing soil total phosphorous (TP) content significantly, resulting in increased C/P and N/P ratios. Correlation analysis showed that TP was negatively correlated with oxalic acid (OA) and acetic acid (AA), indicating that increased AA and OA content could accelerate the active utilization of phosphorus and induced low TP in soil. Re-vegetation with A. ordosica significantly decreased the microbial diversity of topsoil. The redundancy analysis showed that TP was main index in affecting microbes. These results that lower P content, higher C/P and N/P ratio and influence of TP on microbes suggest that phosphorus is the main limiting factor for re-vegetation and growth of soil microorganisms. In the future, strategies for the development of sustainable ecosystems in regions suffers from severe soil erosion should consider phosphorus supplementation.

Arbuscular mycorrhizal fungi affecting the growth, nutrient uptake and phytoremediation potential of different plants in a cadmium-polluted soil.

Heavy metals stress is of great concern as it contaminates the environment affecting human health and the growth and quality of different plants including the medicinal ones. The use of soil microbes is among the most efficient methods for treating heavy-metal polluted soils. The objective was to investigate the effects of arbuscular mycorrhizal (AM) fungi (Glomus mosseae) on the nutrient uptake (N, P, K, Fe, and Mn,) and Cd removal of different plants including rosemary (Salvia rosmarinus), amaranth (Amaranthus sp.), and ornamental cabbage (Brassica oleracea) in a Cd-polluted soil. The experiment was a three-way factorial on the basis of a randomized complete block design with three replicates. The experimental soil was sprayed with Cd (0, 10, 25, 50, 75 and 100 mg kg-1), and after 2 months it was inoculated with 100 g of mycorrhizal inoculums, and was planted in 4-kg pots. Plant growth (root and aerial part) and nutrient uptake as well as Cd removal from the contaminated soil were significantly affected by the experimental treatments. AM fungi significantly increased plant P uptake (35%) compared with N (24%), K (4%), Fe (24%) and Mn (13%). According to the results, rosemary was the most effective plant for the bioremediation of the soil. There were significant differences between plant roots and aerial part in terms of plant nutrient uptake and phytoremediation potential. Although increasing Cd concentration decreased plant growth and nutrient uptake, mycorrhizal fungi was able to alleviate the stress by significantly increasing plant growth, nutrient uptake and phytoremediation potential.

Effects of mycorrhiza and hyphae on the response of soil microbial community to warming in eastern Tibetan Plateau.

The effects of mycorrhiza and its external hyphae on the response of soil microbes to global warming remain unclear. This study investigates the role of mycorrhiza and its hyphae in regulating soil microbial community under warming by examining the microbial biomass and composition in the ingrowth cores of arbuscular mycorrhiza (AM) plant, Fargesia nitida, and ectomycorrhiza (ECM) plant, Picea asperata, with/without mycorrhiza/hyphae and experimental warming. The results showed that warming significantly increased the biomass of all soil microbes (by 19.89%-137.48%) and altered the microbial composition in both plant plots without mycorrhiza/hyphae. However, this effect was weakened in the presence of mycorrhiza or hyphae. In F. nitida plots, warming did not significantly affect biomass and composition of most soil microbial groups when mycorrhiza or hyphae were present. In P. asperata plots, warming significantly increased the total and ECM fungi (ECMF) biomass in the presence of hyphae (p < 0.05) and the total, Gn, and AM fungi (AMF) biomass in the presence of mycorrhiza (p < 0.05). Meanwhile, the response of enzyme activities to warming was also altered with mycorrhiza or hyphae. Additionally, soil microbial community composition was mainly influenced by soil available phosphorus (avaP), while enzyme activities depended on soil avaP, dissolved organic carbon (DOC), and nitrate concentrations. Our results indicate that mycorrhiza and its hyphae are essential in regulating the response of microbes to warming.

Goethite modified biochar simultaneously mitigates the arsenic and cadmium accumulation in paddy rice (Oryza sativa) L.

Cadmium (Cd) and arsenic (As) contamination of paddy soils is a serious global issue because of the opposite geochemical behavior of Cd and As in paddy soils. Rice plant (Oryza sativa L.) cultivation in Cd- and As- contaminated paddy soil is regarded as one of the main dietary cause of Cd and As entry in human beings. This study aimed to determine the impact of goethite-modified biochar (GB) on bioavailability of both Cd and As in Cd- and As- polluted paddy soil. Contrary to control and biochar (BC) amendments, the application of GB amendments significantly impeded the accumulation of both Cd and As in rice plants. The results confirmed an obvious reduction in Cd and As content of rice grains by 85% and 77%, respectively after soil supplementation with GB 2% amendment. BC 3% application minimized the Cd uptake by 59% in the rice grains as compared to the control but exhibited a little impact on As accumulation in rice grains. Sequential extraction results displayed an increase in immobile Cd and As fractions of the soil by decreasing the bioavailable fractions of both elements after GB treatments. Fe-plaque formation on the root surfaces was significantly variable (P Ë‚ 0.05) among all the amendments. GB 2% treatment significantly increased the Fe content (10 g kg-1) of root Fe-plaque by 48%, which ultimately enhanced the sequestration of Cd and As by Fe-plaque and minimized the transport of Cd and As in rice plants. Moreover, GB treatments significantly changed the relative abundance of the microbial community in the rice rhizosphere and minimized the metal(loid)s mobility in the soil. The relative abundance of Acidobacteria, Firmicutes and Verrucomicrobia increased with GB 2% treatment while those of Bacteroidetes and Choloroflexi decreased. Our findings confirmed improvement in the rice grains quality regarding enhanced amino acid contents with GB application. Overall, the results of this study demonstrated that GB amendment simultaneously alleviated the Cd and As concentrations in edible parts of rice plant and provided a new valuable method to protect the public health by effectively remediating the co-occurrence of Cd and As in paddy soils.

Arbuscular Mycorrhizal Fungi Compete Asymmetrically for Amino Acids with Native and Invasive Solidago.

Arbuscular mycorrhizal fungi (AMF) and soil amino acids both affect plant performance. However, little is known about how AMF compete for amino acids with native and invasive congeners. We conducted a factorial experiment (inoculation, native and invasive species, and amino acids) to examine the competition for amino acids between soil microbes and both native and invasive congeners. The competition for amino acids between AMF and invasive Solidago canadensis was weaker than that observed between AMF and native S. decurrens. This asymmetric competition increased the growth advantage of S. canadensis over S. decurrens. The efficacy (biomass production per unit of nitrogen supply) of amino acids compared to ammonium was smaller in S. canadensis than in S. decurrens when both species were grown without inoculation, but the opposite was the case when both species were grown with AMF. AMF and all microbes differentially altered four phenotypic traits (plant height, leaf chlorophyll content, leaf number, and root biomass allocation) and the pathways determining the effects of amino acids on growth advantages. These findings suggest that AMF could enhance plant invasiveness through asymmetric competition for amino acids and that amino acid-driven invasiveness might be differentially regulated by different microbial guilds.

Selenium improved the combined remediation efficiency of Pseudomonas aeruginosa and ryegrass on cadmium-nonylphenol co-contaminated soil.

Most chemical plant wastewater contains both organic and inorganic pollutants, which are easy to diffuse along with surface runoff. The combined pollution of nonylphenol (NP) and cadmium (Cd) in soil is a serious problem that has not attracted enough attention. Based on the effects of selenium (Se) and Pseudomonas aeruginosa (P. aeruginosa) on plant and soil microbial communities, we speculated that the application of Se and P. aeruginosa in soil could improve the phytoremediation efficiency of ryegrass on contaminated soil. In this study, pot experiments with Cd and NP co-contaminated soil were conducted, and the results showed that application of P. aeruinosa alone could improve the removal rates of NP and Cd by ryegrass, and the supplementary of Se further enhanced the effect of micro-phyto remediation, with the highest removal rates of NP and Cd were 79.6% and 49.4%, respectively. The application of P. aeruginosa plus Se reduced the adsorption of Cd and NP through C-O and Si-O-Fe of the soil, changed the enzyme activity, and also affected the changing trend of the microbial community in soil. Pseudomonas, Sphingomonadales, Nitrospira, and other beneficial bacteria were enriched after a 60-day period with P. aeruginosa and Se treatment, thus promoting the removal of NP and Cd. In light of the above results, we suggest that P. aeruginosa application can efficiently facilitate the phytoremediation of ryegrass on Cd-NP co-contaminated soil, and Se supplementation in soil showed the synergistic effect on the remediation.

Dynamics of community structure and bio-thermodynamic health of soil organisms following subtropical forest succession.

Soil organisms play essential roles in maintaining multiple ecosystem processes, but our understanding of the dynamics of these communities during forest succession remains limited. In this study, the dynamics of soil organism communities were measured along a 3-step succession sequence of subtropical forests (i.e., a conifer forest, CF; a mixed conifer and broad-leaved forest, MF; and a monsoon evergreen broad-leaved forest, BF). The eco-exergy evaluation method was used as a complement to the classic community structure index system to reveal the holistic dynamics of the bio-thermodynamic health of soil organism communities in a forest succession series. Association between the self-organization of soil organisms, soil properties, and plant factors were explored through redundancy analyses (RDA). The results indicated that the biomass of soil microbes progressively increased in the dry season, from 0.75 g m-2 in CF to 1.75 g m-2 in BF. Microbial eco-exergy showed a similar pattern, while the community structure and the specific eco-exergy remained constant. Different trends for the seasons were observed for the soil fauna community, where the community biomass increased from 0.72 g m-2 to over 1.97 g m-2 in the dry season, but decreased from 3.94 g m-2 to 2.36 g m-2 in the wet season. Faunal eco-exergies followed a similar pattern. Consequently, the average annual biomass of the soil faunal community remained constant (2.17-2.39 g m-2) along the forest succession sequence, while the significant seasonal differences in both faunal biomass and eco-exergy observed at the early successional stage (CF) were insignificant in the middle and late forest successional stages (MF and BF). Both the dynamics of soil microbes and soil fauna were tightly correlated with tree biomass and with soil physicochemical properties, especially soil pH, moisture, total nitrogen, nitrate nitrogen, and organic matter content.

Thymus Citriodorus (Schreb) Botanical Products as Ecofriendly Nematicides with Bio-Fertilizing Properties.

In recent years, interest has surged in the development of plant extracts into botanical nematicides as ecofriendly plant protection products. Aromatic plants are maybe the most studied category of botanicals used in this direction and the yielding essential oils are obtained on a commodity scale by hydro distillation. Nevertheless, can the bioactivity of aromatic plants always be attributed to the terpenes content? What would it mean for soil microcosms to bear the treatment of an essential oil to cure against Meloidogyne sp.? Are there other extraction procedures to prepare more ecofriendly botanical products starting from an aromatic material? Lemon thyme is studied herein for the first time for its nematicidal potential. We compare the efficacy of lemon thyme powder, macerate, water extract and essential oil to control Meloidogyne incognita (Chitwood) and Meloidogyne javanica (Chitwood), and we additionally study the secondary effects on soil microbes and free-living nematodes, as well as on tomato plant growth. According to our results lemon thyme powder enhances tomato plants' growth in a dose-response manner and when it is incorporated in soil at 1 g kg-1, it exhibits nematicidal activity at a 95% level on M. incognita. The water extract yielding from the same dose is nematicidal only if it is left unfiltered; otherwise only a paralysis effect is demonstrated but inside the soil the biological cycle of the pest is not arrested. The essential oil is good both in performing paralysis and biological cycle arrest, but it detrimentally lowers abundances of bacterial and fungal feeding nematodes. On the contrary, lemon thyme powder and unfiltered water extract augments the bacterial biomass, while the latter also increases the bacterivorous nematodes. Overall, the bio fertilizing lemon thyme powder and its unfiltered water extract successfully control root knot nematodes and are beneficial to soil microbes and saprophytic nematodes.

Response of Soil Microbes to Vegetation Restoration in Coal Mining Subsidence Areas at Huaibei Coal Mine, China.

Vegetation restoration is an available way to ameliorate degraded lands. In order to study the response of soil microbes to vegetation restoration in coal mining subsidence areas, the composition and distribution of soil microbes were discussed through three plots: unsubsided area (CA), new subsided area (NSA), and old subsided area (OSA) with different vegetation restoration time in Huabei coal mine. Meanwhile, changes in soil catalase and urease activity were explored and the correlation between soil bacteria, fungi, and environmental factors was analysed. The results demonstrated that Nitrospira was the dominant bacteria in all areas sampled. Microorganisms in the 0-20 cm and 40-60 cm soil layers of OSA had the highest Simpson index, whereas the index in NSA was lowest (at all soil depths). The catalase activity in NSA was significantly higher than that in CA, and there was no significant difference in catalase activity with soil depth, while the urease activity declined gradually with increasing soil depth. The urease activity in the 20-60 cm soil layer of NSA and OSA was significantly higher than that of CA. Furthermore, the distribution of bacteria was mainly affected by soil organic matter, available potassium, available phosphorus, and alkali-hydrolyzable nitrogen, whereas pH and catalase activity mainly affected fungal distribution. These results implied that soil catalase activity in NSA and urease activity in the 20-40 cm soil layer of NSA and OSA were significantly enhanced after vegetation restoration, and that long-term plant restoration could improve soil fertility and soil microbial community diversity in coal mining areas.

Little evidence that farmers should consider abundance or diversity of arbuscular mycorrhizal fungi when managing crops.

Contents Summary 1092 I. Introduction 1093 II. Investigating activity of AMF in agroecosystems 1093 III. Crop benefit from AMF: agronomic and mycorrhizal literature differ 1094 IV. Flawed methodology leads to benefits of mycorrhizas being overstated 1094 V. Rigorous methodology suggests low colonisation by AMF can sometimes reduce crop yield 1095 VI. Predicting when mycorrhizas matter for crop yield 1096 VII. Crop genotype 1099 VIII. Fungal genotype 1100 IX. Complex interactions between the mycorrhizal fungal and soil microbial communities 1102 X. Phosphorus-efficient agroecosystems 1102 XI. Conclusions 1103 Acknowledgements 1104 References 1104 SUMMARY: Arbuscular mycorrhizal fungi (AMF) are ubiquitous in agroecosystems and often stated to be critical for crop yield and agroecosystem sustainability. However, should farmers modify management to enhance the abundance and diversity of AMF? We address this question with a focus on field experiments that manipulated colonisation by indigenous AMF and report crop yield, or investigated community structure and diversity of AMF. We find that the literature presents an overly optimistic view of the importance of AMF in crop yield due, in part, to flawed methodology in field experiments. A small body of rigorous research only sometimes reports a positive impact of high colonisation on crop yield, even under phosphorus limitation. We suggest that studies vary due to the interaction of environment and genotype (crop and mycorrhizal fungal). We also find that the literature can be overly pessimistic about the impact of some common agricultural practices on mycorrhizal fungal communities and that interactions between AMF and soil microbes are complex and poorly understood. We provide a template for future field experiments and a list of research priorities, including phosphorus-efficient agroecosystems. However, we conclude that management of AMF by farmers will not be warranted until benefits are demonstrated at the field scale under prescribed agronomic management.

[Effects of Long-term Fertilization Regimes on Microbial Biomass, Community Structure and Activity in a Paddy Soil].

Four paddy soils were collected in Ningxiang County, Hunan province. These used with different long-term fertilization regimes, including a control without fertilizer (CK), chemical fertilization with nitrogen, phosphate, and kalium (NPK), straw fertilization combined with NPK (ST), and manure fertilization combinedwith NPK (OM). Phospholipid fatty acid (PLFA) technology and MicrorespTM method were used to study the effect of long-term fertilization on soil microorganism abundance, community structure, and activity. Results showed that the abundance of bacteria, fungi, gram-negative (G-) bacteria, and gram-positive (G+) bacteria in the soil from the OM treatment was generally higher than for the other treatments; these levels were lower in the ST and NPK treatments and lowest in the CK treatment. The principal components analysis (PCA) of PLFA showed that the community structure of microorganisms in NPK, ST, and OM treatments was altered in comparison with that in CK, especially in the case of the ST and OM treatments. MicroRespTM results revealed that compared to the CK treatment (1.28 µg·h-1), soil microorganisms in the OM treatment had the highest average utilization rate of multiple carbon sources (1.81 µg·h-1), followed by ST (1.19 µg·h-1), CK (1.28 µg·h-1), and NPK (0.95 µg·h-1). Furthermore, different long-term fertilization regimes resulted in distinct carbon source preferences for the soil microorganisms and revealed a significant alteration in the microbial community. Conclusively, long-term fertilizer with straw or manure changes the microbial community and is a benefit for improving the biomass and activity of microorganism in rice paddy soils.

Crop acquisition of phosphorus, iron and zinc from soil in cereal/legume intercropping systems: a critical review.

BACKGROUND: Phosphorus (P), iron (Fe) and zinc (Zn) are essential elements for plant growth and development, but their availability in soil is often limited. Intercropping contributes to increased P, Fe and Zn uptake and thereby increases yield and improves grain nutritional quality and ultimately human health. A better understanding of how intercropping leads to increased plant P, Fe and Zn availability will help to improve P-fertilizer-use efficiency and agronomic Fe and Zn biofortification. SCOPE: This review synthesizes the literature on how intercropping of legumes with cereals increases acquisition of P, Fe and Zn from soil and recapitulates what is known about root-to-shoot nutrient translocation, plant-internal nutrient remobilization and allocation to grains. CONCLUSIONS: Direct interspecific facilitation in intercropping involves below-ground processes in which cereals increase Fe and Zn bioavailability while companion legumes benefit. This has been demonstrated and verified using isotopic nutrient tracing and molecular analysis. The same methodological approaches and field studies should be used to explore direct interspecific P facilitation. Both niche complementarity and interspecific facilitation contribute to increased P acquisition in intercropping. Niche complementarity may also contribute to increased Fe and Zn acquisition, an aspect poorly understood. Interspecific mobilization and uptake facilitation of sparingly soluble P, Fe and Zn from soil, however, are not the only determinants of the concentrations of P, Fe and Zn in grains. Grain yield and nutrient translocation from roots to shoots further influence the concentrations of these nutrients in grains.

Kinetics of aerobic and anaerobic biomineralization of atrazine in surface and subsurface agricultural soils in Ohio.

The purpose of this study was to assess atrazine mineralization in surface and subsurface samples retrieved from vertical cores of agricultural soils from two farm sites in Ohio. The Defiance site (NW-Ohio) was on soybean-corn rotation and Piketon (S-Ohio) was on continuous corn cultivation. Both sites had a history of atrazine application for at least a couple of decades. The clay fraction increased at the Defiance site and the organic matter and total N content decreased with depth at both sites. Mineralization of atrazine was assessed by measurement of (14)CO2 during incubation of soil samples with [U-ring-(14)C]-atrazine. Abiotic mineralization was negligible in all soil samples. Aerobic mineralization rate constants declined and the corresponding half-lives increased with depth at the Defiance site. Anaerobic mineralization (supplemented with nitrate) was mostly below the detection at the Defiance site. In Piketon samples, the kinetic parameters of aerobic and anaerobic biomineralization of atrazine displayed considerable scatter among replicate cores and duplicate biometers. In general, this study concludes that data especially for anaerobic biomineralization of atrazine can be more variable as compared to aerobic conditions and cannot be extrapolated from one agricultural site to another.

The Effect of Nano-Silver Liquid against the White Rot of the Green Onion Caused by Sclerotium cepivorum

White rot, which is caused by Sclerotium cepivorum, is a lethal disease affecting green onions. Three different types of nano-silver liquid (WA-CV-WA13B, WA-AT-WB13R, and WA-PR-WB13R) were tested in several different concentrations on three types of media to assess their antifungal activities. Results from in vitro experiments showed that all three of the nano-silver liquids had more than 90% inhibition rates at a concentration of 7 ppm. Greenhouse experiments revealed that all of the nano-silver liquids increased biomass and dry weights, and there were minimal changes in the population of various bacteria and fungi from the soil of greenhouse-cultivated green onions. In addition, a soil chemical analysis showed that there were minimal changes in soil composition.