Microbial Fertilizer: A Sustainable Strategy for Medicinal Plants Production

Medicinal plants have aroused considerable interest as an alternative to chemical drugs due to the beneficial effects of their active secondary metabolites.However,the extensive use of chemical fertilizers and pesticides in pursuit of yield has caused serious pollution to the environment,which is not conducive to sustainable devel-opment in thefield of medicinal plants.Microbial fertilizers are a type of“green fertilizer”containing specific microorganisms that can improve the soil microbial structure,enhance plant resistance to biological and abiotic stresses,and increase the yield of medicinal plants.The root exudates of medicinal plants attract different micro-organisms to the rhizosphere,which then migrate further to the plant tissues.These microbes can increase the levels of soil nutrients,and improve the physical and chemical properties of soil through nitrogenfixation,and phosphorus and potassium solubilization.In addition,soil microbes can promote the synthesis of hormones that increase plant growth and the accumulation of active compounds,eventually improving the quality of med-icinal plants.In 2022,the total value of the global microbial fertilizer market was$4.6 billion and is estimated to reach$10.36 billion by 2030.In this review,we have summarized the types of microbial fertilizers,the coloniza-tion and migration of microorganisms to plant tissues,and the beneficial effects of microbial fertilizers.In addi-tion,the prospects of developing microbial fertilizers and their application for medicinal plants have also been discussed.It aims to provide a reference for the rational application of microbial fertilizers in thefield of med-icinal plants and the green and sustainable development of medicinal plant resources.

Effects of Microbial Fertilizers in Improving Acidic Tobacco-planting Soil and Tobacco Leaf Quality

[Objectives]This study was conducted to improve acidic soil and enhance the quality of tobacco leaves.[Methods]The effects of different microbial fertilizers on improving acidic tobacco-planting soil and tobacco leaf quality were investigated through plot experiments.[Results]The application of microbial fertilizers could improve the pH value of acidic soil,and composite microbial agent A showed the best application effect.The application of bio-organic fertilizer was beneficial to improving the contents of available phosphorus and available boron in acidic soil.The application of composite microbial agent A was beneficial to improving the contents of available phosphorus and available potassium in acidic soil,and could promote the growth of tobacco plants and improve the economic traits of flue-cured tobacco and the coordination of chemical components in tobacco leaves.The application of composite microbial agent B led to a downward trend in the content of available boron in acidic soil.The application of composite microbial agent B could promote the absorption of nutrients by tobacco plants,and improve their disease resistance and the quality of tobacco leaves.Due to the differences in functional microorganisms contained,the application effects of different microbial fertilizers in improving acidic tobacco-planting soil and improving tobacco leaf quality varied.Overall,the application of microbial fertilizers could increase soil pH,activate soil nutrients,promote tobacco growth,enhance disease resistance,increase tobacco output value,and improve tobacco quality.Microbial fertilizers have good application prospects in improving acidic soil and improving tobacco quality.[Conclusions]The application of microbial fertilizers to improve acidic tobacco-planting soil can ensure the normal growth and development of tobacco plants and the improvement of tobacco leaf quality,achieving high-quality and sustainable development of Zhaotong tobacco.

Effects of Microbial Fertilizer and Compound Feritlizer Mixed Application on Yield and Fruit Quality and Flowering and Fruit Setting of Following Year of Apple

In order to study the application effect of microbial fertilizer and compound fertilizer mixed application on microirrigation apple, three types of fertilizers were applied in spring which were urea（CK, 15 kg/plant）, microbial fertilizer（5.0 kg/plant）,microbial fertilizer and compound fertilizer mixed（each 2.5 kg/plant） to study the effect of different fertilizer treatments on yield, fruit quality, flowering and fruit setting of Xinshijie apple. The results showed that application of microbial fertilizer could increase the yield, fruit weight and fruit shape index, significantly increase the flowering rates and inflorescence fruit setting rate of following year, while reduce the fruit hardness and soluble solids content, and the effect of microbial fertilizer and compound fertilizer mixed application on increasing fruit weight and yield was higher than that of microbial fertilizer separate application, the effect of the two was not obvious in other aspects. Therefore, microbial fertilizer could be used instead of some chemical fertilizer and organic fertilizer in apple production to reach the aim of increasing yield and efficiency, and the effect of microbial fertilizer and compound fertilizer mixed application was best.

Effects of Microbial Fertilizer on Growth Characteristics of Facility Tomato and Chemical Properties of Acidic soil

[Objectives]This study was conducted to discuss the possibility of applying microbial fertilizer to production of facility tomato,so as to determine rational application rate for facility tomato.[Methods]A field experiment was carried out to investigate the effects of the application of microbial fertilizer onto acidic soil on yield,quality and soil chemical properties of facility tomato.[Results]Yield of facility tomato was improved after the application of microbial fertilizer.Treatment ABA-2 showed the highest yield,which was higher than the CK by 7.98%.On the basis of conventional fertilization,the combined application with microbial fertilizer could promote growth and development of tomato,and could significantly improve fruit weight,and Vc,soluble solid and lycopene contents.Furthermore,the microbial fertilizer could remarkably improve soil p H,alkali-hydrolyzale nitrogen,available phosphorus and rapidly available potassium contents.[Conclusions]The application of microbial fertilizer at 80 kg/667 m^(2) has better effects on tomato growth and development and soil status.

Field Efficiency Trial of Microbial Fertilizer against Eggplant Verticillium Wilt

The control effect of microbial fertilizer on eggplant verticillium wilt was studied through investigation of disease index and diseased plant rate. The reiults showed that the disease index and diseased plant rate of eggplant verticillium wilt were the lowest in the plots with substrate treatment and root-irrigation treatnent. The control effects in the plots with substrate treatment were higher than those in the plots with only root irrigation treatment. Moreover, higher concentration of microbial fertilizer resulted in better control effect and higher yield. Thus, the microbial fertilizer had a broad application prospect.

Effect of Kelp Residue Microbial Fertilizer on Eco-Control Peanut Pathogenic Fungus Aspergillus Parasiticus 1

Ecological prevention and control of plant disease is very important in sustainable agriculture.Adjusting soil p H value and fertilizing organic microbial fertilizer are two effective measures in this process.Kelp residue contains a large amount of organic compounds and alkaline metal ions.The bio-control Bacillus amyloliquefaciens strain Hitwh-BA2 was inoculated into kelp residue medium to produce kelp residue microbial fertilizer.Acidic soil and alkaline soil were used to study the effect of kelp residue microbial fertilizer on soil p H and soil suppressive activity.Tip-culture method was used to determine soil leachate suppressive activity,which characterized the soil suppressive activity.Results showed that fertilizing kelp residue microbial fertilizer had increased the soil p H and soil suppressive ability significantly,which was verified by peanut validation experiments as well.Peanut potting experiments proved that fertilizing kelp residue microbial fertilizer not only improved the yield of peanuts obviously,but also reduced the amount of Aspergillus parasiticus 95 in peanut geocarposphere soil significantly.Results also showed that fertilizing kelp residue microbial fertilizer was effective in reducing A.parasiticus 95 infection rate.So the kelp residue microbial fertilizer has good potential application prospect on ecological prevention and control of plant disease.

Effect of Microbial Inoculum Fertilizer on the Growth and Yield of Super Hybrid Rice

The research designed four application quantities of 0, 2 250, 4 500 and 6 750 g/hm2 based on Liangyou No. 959 to explore the effects of microbial inocu- lure fertilizer on growth and yield of super hybrid rice. The results indicate that the treatment with traditional fertilizers and 4 500 g/hm2 HYT microbial inoculum fertilizer performed the best, where average number of tiller was 2.4 more than that of the control; the number of effective ear was 11.05% higher; yield increased by 10.3%. These have demonstrated that microbial inoculum fertilizer is of great value in pro- motion on super hybrid rice production.

Study on Effect of Engran Series of Microbial Organic Fertilizers on Flue-cured Tobacco

[Objective] This study was conducted to provide theoretic support for improving yield and quality of flue-cured tobacco by applying microbial organic fertilizers. [Method] A field plot experiment was conducted to study the effects of the Engran series of microbial organic fertilizers on growth and development, diseases and pests and economic traits of flue-cured tobacco. [Result] The result showed that the treatment of conventional fertilization ＋ Engran microbial agent could promote the growth and dry matter accumulation of flue-cured tobacco during the growth period in the field, enhance the disease resistance of tobacco, and improve yield and output value of flue-cured tobacco and income of tobacco growers. Compared with T1,the proportion of high-grade tobacco, the proportion of mid-high grade tobacco,yield, output value and average price increased by 4.4%, 3.8%, 5.48%, 11.51% and5.73% respectively. [Conclusion] The treatment of conventional fertilization ＋ Engran microbial agent showed outstanding performance, is optimum for field production,and could be applied to Flue-cured tobacco.

Preparation and efficacy evaluation of Paenibacillus polymyxa KM2501-1 microbial organic fertilizer against root-knot nematodes

Root-knot nematodes(RKNs) cause huge yield losses to agricultural crops worldwide. Meanwhile, livestock manure is often improperly managed by farmers, which leads to serious environmental pollution. To resolve these two problems, this study developed a procedure for the conversion of chicken manure to organic fertilizer by larvae of Hermetia illucens L. and Bacillus subtilis BSF-CL. Chicken manure organic fertilizer was then mixed thoroughly with Paenibacillus polymyxa KM2501-1 to a final concentration of 1.5×10^(8)CFU g^(-1). The efficacy of KM2501-1 microbial organic fertilizer in controlling root-knot nematodes was evaluated in pot and field experiments. In pot experiments, applying KM2501-1 microbial organic fertilizer either as a base fertilizer or as a fumigant at the dose of 40 g/pot suppressed root-knot disease by 61.76 and 69.05% compared to the corresponding control treatments, respectively. When applied as a fumigant at the dose of 1 kg m;in field experiments, KM2501-1 microbial organic fertilizer enhanced the growth of tomato plants, suppressed root-knot disease by 49.97%, and reduced second stage juveniles of RKN in soil by 88.68%. KM2501-1 microbial organic fertilizer controlled RKNs better than commercial bio-organic fertilizer in both pot and field experiments. These results demonstrate that this co-conversion process efficiently transforms chicken manure into high value-added larvae biomass and KM2501-1 microbial organic fertilizer with potential application as a novel nematode control agent.

Impact of Microbial Inoculants on Microbial Quantity, Enzyme Activity and Available Nutrient Content in Paddy Soil

The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in Heilongjiang Province. The application of soil phosphorus activator was able to increase the quantity of bacteria and fungi in soil, but its effect on actinomycetes in soil was not significant. The application of microbial inoculants increased the urease and sucrase activities in soil over the growing season, but only at the maturing stage soil acid phosphatase activity was enhanced with the applying soil phosphorus activator. The application of soil phosphorus activator increased alkali-hydrolyzable nitrogen and available phosphorus contents in soil, but did not increase available potassium content in soil. The optimal microbial inoculant application rate as applied as soil phosphorus activator was 7.5 kg hm-2.

Application of Aisi Si/TE Compound Bacterial Fertilizer in Rice

[Objectives]To investigate the application effect of compound microbial fertilizer on crops.[Methods]Livestock and poultry breeding waste,rapeseed cake and peanut straw were fully decomposed,and then added with compound functional microbial inoculum to produce Aisi Si/TE(active chelated silicon/trace element)compound microbial fertilizer,which was used to conduct 10%nitrogen reduction alternative fertilization experiment on rice.[Results]The yield of rice applied with 225 kg/ha Aisi Si/TE compound bacterial fertilizer was 7203 kg/ha,increased by 5.4%,6.9%and 46.9%,respectively compared to those of rice applied with 225 kg/ha inactivated Aisi Si/TE compound microbial fertilizer,conventional fertilization and blank control(P<0.01).Application of Aisi Si/TE compound microbial fertilizer to rice improved soil organic matter and effective nutrient content and showed obvious effect of saving nitrogen and increasing yield and income.In addition,it provided a good micro-ecological environment,passivated and solidified heavy metals,effectively reduced the biological mobility of heavy metals,and greatly reduced the cadmium content in rice.[Conclusions]Application of Aisi Si/TE compound microbial fertilizer is beneficial to improving the quality of agricultural products.

Microbial community structure and functional metabolic diversity are associated with organic carbon availability in an agricultural soil

Exploration of soil environmental characteristics governing soil microbial community structure and activity may improve our understanding of biogeochemical processes and soil quality. The impact of soil environmental characteristics especially organic carbon availability after 15-yr different organic and inorganic fertilizer inputs on soil bacterial community structure and functional metabolic diversity of soil microbial communities were evaluated in a 15-yr fertilizer experiment in Changping County, Beijing, China. The experiment was a wheat-maize rotation system which was established in 1991 including four different fertilizer treatments. These treatments included： a non-amended control（CK）, a commonly used application rate of inorganic fertilizer treatment（NPK）; a commonly used application rate of inorganic fertilizer with swine manure incorporated treatment（NPKM）, and a commonly used application rate of inorganic fertilizer with maize straw incorporated treatment（NPKS）. Denaturing gradient gel electrophoresis（DGGE） of the 16 S r RNA gene was used to determine the bacterial community structure and single carbon source utilization profiles were determined to characterize the microbial community functional metabolic diversity of different fertilizer treatments using Biolog Eco plates. The results indicated that long-term fertilized treatments significantly increased soil bacterial community structure compared to CK. The use of inorganic fertilizer with organic amendments incorporated for long term（NPKM, NPKS） significantly promoted soil bacterial structure than the application of inorganic fertilizer only（NPK）, and NPKM treatment was the most important driver for increases in the soil microbial community richness（S） and structural diversity（H）. Overall utilization of carbon sources by soil microbial communities（average well color development, AWCD） and microbial substrate utilization diversity and evenness indices（H＇ and E） indicated that long-term inorganic fertilizer with organic amendments incorporated（NPKM, NPKS） could significantly stimulate soil microbial metabolic activity and functional diversity relative to CK, while no differences of them were found between NPKS and NPK treatments. Principal component analysis（PCA） based on carbon source utilization profiles also showed significant separation of soil microbial community under long-term fertilization regimes and NPKM treatment was significantly separated from the other three treatments primarily according to the higher microbial utilization of carbohydrates, carboxylic acids, polymers, phenolic compounds, and amino acid, while higher utilization of amines/amides differed soil microbial community in NPKS treatment from those in the other three treatments. Redundancy analysis（RDA） indicated that soil organic carbon（SOC） availability, especially soil microbial biomass carbon（Cmic） and Cmic/SOC ratio are the key factors of soil environmental characteristics contributing to the increase of both soil microbial community structure and functional metabolic diversity in the long-term fertilization trial. Our results showed that long-term inorganic fertilizer and swine manure application could significantly improve soil bacterial community structure and soil microbial metabolic activity through the increases in SOC availability, which could provide insights into the sustainable management of China＇s soil resource.

Effects of background fertilization followed by co-application of two kinds of bacteria on soil nutrient content and rice yield in Northeast China

With the improvement of living standards,people pay more and more attention to the quality and safety of rice.Microbial agents are favored by the public because they can activate the nutrient supply in the soil,and reduce the residue and application amount of chemical fertilizers and pesticides.Based on the conventional fertilization in the field,Bacillus mucilaginosus and Aspergillus niger were applied,Bacillus mucilaginosus was inoculated at four levels in the paddy soil in the cold region of Heilongjiang Province of China.The effects of different proportions of Bacillus mucilaginosus and Aspergillus niger on the number of soil microorganisms,enzyme activity,microbial biomass,soil biochemical intensity,soil nutrient content,plant nutrient content and yield were studied,and the effects on the plant nutrient content of rice and the nutrient dynamics were discussed.The results showed that a 2.62%-21.20%higher yield of rice obtained from co-application treatments compared with that of the control-blank treatment.Furthermore,the highest yield obtained(10736±65 kg/hm^(2))suggested that the optimized values for the two bacteria applied were 120×10^(11) CFU/hm^(2) for Bacillus mucilaginosus and 15×10^(11) CFU/hm^(2) for Aspergillus niger.Bacillus mucilaginosus can decompose minerals in soil,dissolve potassium and silicon,decompose apatite and release phosphorus into soil.Aspergillus niger can transform the phosphate which cannot be absorbed by plants into soluble phosphate which can be directly absorbed by plants by producing non-volatile acids.In particular,Bacillus mucilaginosus and Aspergillus niger have synergistic effect,and their combined application effect is greater than that of two bacteria alone.Co-application promoted the release of soil soluble silicon,and then increased the silicon content of plants.At the same time,soil microorganism,microbial biomass,enzyme activity and biochemical activity all increased significantly.This study provides an effective way to reduce the amount of chemical fertilizer applied in rice production in cold regions of China.