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Communication

The Application of Tomato Plant Residue Compost and Plant Growth-Promoting Rhizobacteria Improves Soil Quality and Enhances the Ginger Field Soil Bacterial Community

by
Kunhao Xie
1,2,
Mintao Sun
2,
Aokun Shi
2,
Qinghua Di
2,
Ru Chen
2,
Duo Jin
2,
Yansu Li
2,
Xianchang Yu
2,
Shuangchen Chen
1,* and
Chaoxing He
2,*
1
Collage of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471000, China
2
Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
*
Authors to whom correspondence should be addressed.
Agronomy 2022, 12(8), 1741; https://doi.org/10.3390/agronomy12081741
Submission received: 23 June 2022 / Revised: 21 July 2022 / Accepted: 21 July 2022 / Published: 23 July 2022
(This article belongs to the Section Soil and Plant Nutrition)
Browse Figures
Review Reports Versions Notes

Abstract

:
Treating and utilizing vegetable residues may reduce waste and improve rhizosphere soil. This study explored the effects of tomato plant residue compost and plant growth-promoting rhizobacteria (PGPR) on the physicochemical properties and microbial community of ginger field soil. Four treatment procedures were adopted: no compost or PGPR (CK), compost (TC), compost + Bacillus subtilis (TC-BS), and compost +Bacillus amyloliquefaciens SQR9 (TC-BA). The results showed that compared with the CK, TC significantly increased soil organic matter, alkali hydrolyzable nitrogen, available phosphorus, and available potassium by 17.34%, 21.66%, 19.56%, and 37.20%, respectively. Soil urease activity, neutral phosphatase activity, and sucrase activity increased by 55.89%, 35.59%, and 57.21%, respectively. Chloroflexi, Gemmatimonadetes, and Bacillus abundances increased by 1.40%, 1.80%, and 0.68%, respectively, while Firmicutes decreased by 0.80%. TC-BS significantly improved soil bacterial diversity than CK and TC, and relative abundance of Beneficial Proteobacteria, Acidobacteria, Chloroflexi, and Bacillus microorganisms dominated. Principal coordinate analysis revealed significant differences in bacterial community structure among different treatments. Redundancy analysis indicated total potassium (p = 0.002), pH (p = 0.0012), and available phosphorus (p = 0.016) as the main community composition driving factors. In conclusion, B. subtilis inoculation in ginger field soil supplemented with tomato compost enhanced bacterial diversity, altered bacterial community structure, enriched beneficial microorganisms, and promoted a healthy rhizosphere.

1. Introduction

With the rapid development of vegetable production in China, explosive growth has occurred in protected vegetable crop cultivation, bringing with it an increase in the amount of vegetable residues that lack economic value, such as roots, stems, and leaves [1]. Without a rational and effective treatment method, these vegetable residues are often disposed of carelessly, causing serious resource waste and environmental pollution [2]. In ginger production, growers apply large quantities of synthetic fertilizers in pursuit of yield and profit, resulting in environmental issues such as reduced soil organic matter (SOM), increased soil acidification and degradation, the destruction of microbial populations, and soil hardening [3,4]. Vegetable residue is usually high in water content, has a low C/N ratio, and can carry harmful pathogens [5]. Thus, the formation of pollution-free organic matter through high-temperature composting and the fermentation of vegetable residue for improving the soil environment of ginger roots has been demonstrated to be an effective way to utilize vegetable wastes as resources.
Soil microorganisms form the most biodiverse communities in the biosphere. They provide important ecosystem services, including services related to soil fertility, carbon sequestration, and plant productivity and health. Bacteria and fungi usually comprise the dominant species in terms of soil microbial biomass and diversity, and participate in processes including soil nutrient cycling and decomposition [6,7]. Soil enzymes secreted by soil microorganisms also play important roles in nutrient cycling, soil structure, and crop production [8]. Studies have shown that the long-term application of organic fertilizers increases the total microbial biomass and fungal abundance of alluvium in northern China but reduces bacterial abundance [9]. Crop residue, however, has a significant influence on the structure of bacterial communities, and helps to increase the relative abundances of Bacteroidetes, Betaproteobacteria, Cyanobacteria, and Gemmatimonadetes [10]. Meng et al. [11] have demonstrated that in the intensively managed agricultural areas of northern China, the combined use of nitrogen fertilizer and straw return promotes organic carbon sequestration and the retention of nitrogen from fertilizer. In addition, Kong et al. [12] reported that the joint application of straw and pig manure could significantly improve soil fertility and bacterial diversity in arid lands.
In recent years, an increasing number of plant rhizosphere bacteria have been commercialized [13]. These bacteria directly or indirectly promote plant growth and yield [14], and compete with pathogenic microbial populations for ecological niches. Changes in microbial diversity and species abundance can also be achieved via the inoculation of beneficial microorganisms (such as Bacillus subtilis and Trichoderma spp.) in soil [15]. Bacillus spp. have been found to secrete extracellular metabolites antagonistic to plant pathogens, including antibiotics, cell wall hydrolases, and iron carriers [16,17]. For example, in a previous study the foliar spraying of water-soluble fertilizers containing Bacillus amyloliquefaciens SQR9 on pepper and cabbage plants significantly increased the bacteria count and reduced the fungal count [18]. The combined application of B. subtilis NCD-2 and broccoli residue has been shown to effectively suppress the occurrence of potato Verticillium wilt, achieving a 37.85% prevention of the disease and a 27.12% increase in potato yield, while reducing the fungal diversity in the rhizosphere soil [19]. In a short-term study, Hui et al. [20] revealed that Firmicutes, Actinobacteria, Lysobacter, and Sphingopyxis became enriched after B. amyloliquefaciens DT inoculation, while Ascomycota was consumed, these results validated the disease inhibition role played by B. amyloliquefaciens DT in community structure.
Several plant growth-promoting rhizobacteria (PGPR) strains have been reported in recent years, but few have broad-spectrum efficacy and strong adaptability, possibly since PGPR require a complex living environment and are sensitive to external factors, such as soil fertility, soil physical and chemical properties, and crop species [21]. As single-strain, single-function fertilizers no longer meet the needs of modern-day agriculture, the combined use of PGPR and organic fertilizers could supply multiple functions and improve the environmental adaptability of PGPR [22].
At present, most studies have focused on the return of tomato residues from field crops or greenhouse vegetable [23,24]. No reported studies are available on soil environment improvement in ginger fields through the application of high-temperature composted tomato plant residue, and it still remains unclear whether the combined application of tomato residue compost and PGPR has a positive effect on the ginger field soil environment. In order to reduce the adverse effects of continuous cropping and vegetable waste on soil quality, we explored the effects of tomato plant residue compost and PGPR on the physicochemical properties, soil enzyme activity and microbial community of ginger field soil. We found that B. subtilis inoculation in ginger field soil supplemented with tomato compost enhanced bacterial diversity, altered bacterial community structure, enriched beneficial microorganisms, and promoted a healthy rhizosphere, providing a better understanding of the technical feasibility of the application of in resource utilization of vegetable residues and sustainable cultivation of ginger.

2. Materials and Methods

2.1. Test Field Conditions

The study was conducted in the field at the Nankou Pilot Base of the Chinese Academy of Agricultural Sciences in Beijing, China from April to November 2021. The test site is located in an area with a semi-humid, semi-arid temperate continental monsoon climate, with an annual average temperature of 11.8 °C and precipitation of 550.3 mm. The soil type is loam, the previous crop planted was onion. Before ginger cultivation, the conditions of the topsoil (0–20 cm) were as follows: 23.00 g/kg soil organic matter (SOM), 1.29 g/kg total nitrogen (TN), 1.56 g/kg total phosphorus (TP), 24.80 g/kg total potassium (TK), 107.1 mg/kg alkali hydrolyzable nitrogen (AN), 296 mg/kg available potassium (AK), 234.2 mg/kg available phosphorus (AP), 7.66 mg/kg arsenic (As), 0.168 mg/kg hydrargyrum (Hg), 29.3 mg/kg lead (Pb), 7.61 pH, and 3.6 ms/m electrical conductivity (EC).

2.2. Experimental Materials

A cultivar of Burmese ginger was used in this study. Tomato plant residue obtained from the solar greenhouse of the Nankou Pilot Base of the Chinese Academy of Agricultural Sciences was used for composting. After the fall harvest, the plant roots were removed, and the plants were piled in the fermentation tank and covered with plastic film for high-temperature fermentation. During this period, the temperature was maintained at above 55–60 °C for 15 days. The fermentation system was ventilated with air blowers every morning, noon, and evening to purge CO2 and replenish oxygen, thereby accelerating the fermentation process. Water was sprayed on the fermentation tank regularly to increase the moisture content of the compost. The tank was turned once a week to ensure the thorough fermentation of the compost. The temperature at the center of the compost and the ambient temperature were monitored with an agro-environmental monitor (Beijing Qishuo Foundation Technology Co., Ltd., Beijing, China). Ventilation and compost turning were performed until the temperature became stable, after which the compost was left in the fermentation tank for later use. The nutrient composition of the compost was as follows: 35.2% total carbon (TC), 1.65% TN, 0.763% TP, 3.97% TK, and 2.13 C: N.
Two kinds of commercial PGPR B. subtilis and B. amyloliquefaciens SQR9 were used in this study. The dry PGPR inoculants was produced by Jining Jinshan Biotechnology Co., Ltd., (Jining, China) via three-stage liquid fermentation, (The preparation method was). With a total viable bacteria count of 10 × 1010 bacteria/g, microorganism contamination ≤1%, a sporulation rate ≥98%, and water content ≤8%.

2.3. Experimental Design

Ginger planting furrows of 7 m (length) × 0.35 m (wide) × 0.15–0.2 m (depth) were plowed 0.7 m apart. Ginger plants were grown at a 0.2-m interval to achieve a planting density of 6.65 plants/m2. Four treatment procedures were used on the plants: no tomato plant residue compost or PGPR (CK), tomato plant residue compost (TC), tomato plant residue compost +B. subtilis (TC-BS), and tomato plant residue compost +B. amyloliquefaciens SQR9 (TC-BA). Five plots of land (Five biological repeats), each with an area of 6.4 m2, were randomly assigned under each treatment procedure. Before planting, 15 t/hm2 of refined organic fertilizer and 750 kg/hm2 of ternary fertilizer were applied to the land. The soil was thoroughly mixed with fertilizers and prepared for furrowing. Then, 15,000 kg/hm2 of tomato plant residue compost was applied to the furrows, covered with a thin layer of soil, and 150 kg/hm2 of B. subtilis and B. amyloliquefaciens SQR9 were applied evenly.

2.4. Soil Sample Collection

Soil sampling took place one day before ginger harvest (19 October 2021). Soil samples were taken from six sampling sites arranged in an ‘S’ shape for each treatment procedure. Visible contaminants, such as gravel and roots, were removed. The collected soil was placed into a sterile zip bag and mixed thoroughly. The soil content of each bag was divided into four 5–10 g portions, which were placed in zip bags and wrapped with aluminum foil. These samples were immediately transferred back to the lab in an ice box and stored in a freezer at −80 °C for DNA extraction and sequencing. Any leftover soil was kept in a cool and dry place to air-dry, ground, and passed through a 1-mm sieve for soil nutrient content and enzyme activity measurement.

2.5. Soil Nutrient Content and Enzyme Activity Determination

Soil pH and EC were measured with a multi-parameter water quality analyzer (Models: HQ440D, Manufacturer: HACH, Shanghai). SOM was determined by dichromate oxidation with external heating. TN was determined by the semi-micro Kjeldahl method. AN was quantified by boric acid absorption and the conductometric titration of the ammonia liberated from the NaOH hydrolysis of the soil sample. TP was determined by the molybdenum blue method following perchloric acid-sulfuric acid digestion. AP was determined by the molybdenum blue method following sodium bicarbonate extraction. TK and AK were both measured by atomic absorption spectrometry [25].
Soil urease activity was determined by the sodium phenoxide-sodium hypochlorite method. Neutral phosphatase activity was determined by the disodium phenyl phosphate method. Sucrase activity was determined by the 3, 5-dinitrosalicylic acid method [26].

2.6. Soil DNA Extraction, 16S rRNA Gene Amplicon Sequencing

Total microbial genomic DNA samples were extracted using the DNeasy PowerSoil Kit (QIAGEN, Shanghai Paiseno Biotechnology Co., Ltd., Shanghai, China), following the manufacturer’s instructions and stored at −20 °C prior to further analysis. The quantity and quality of extracted DNAs were measured using a NanoDrop ND-1000 spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA) and agarose gel electrophoresis, respectively [27].
PCR amplification of the bacterial 16S rDNA genes V3–V4 region was performed using the forward primer 338-F (5′-ACTCCTACGGGAGGCAGCA-3′) and the reverse primer 806-R (5′-GGACTACHVGGGTWTCTAAT-3′). Sample-specific 7-bp barcodes were incorporated into the primers for multiplex sequencing. The PCR components contained 5 μL of Q5 reaction buffer (5×), 5 μL of Q5 High-Fidelity GC buffer (5×), 0.25 μL of Q5 High-Fidelity DNA Polymerase (5 U/μL), 2 μL (2.5 mM) of dNTPs, 1 μL (10 uM) of each Forward and Reverse primer, 2 μL of DNA Template, and 8.75 μL of ddH2O. Thermal cycling consisted of initial denaturation at 98 °C for 2 min, followed by 25 cycles consisting of denaturation at 98 °C for 15 s, annealing at 55 °C for 30 s, and extension at 72 °C for 30 s, with a final extension of 5 min at 72 °C [28]. The library construction and sequencing steps were performed by Shanghai Paiseno Biotechnology Co., Ltd., Shanghai, China.

2.7. Soil Microbial Community Analysis

QIIME2 software was used in Paiseno cloud platform to remove primers, quality filtering, denoising, stitching and chimerism, and obtain high-quality sequences for subsequent analysis. Five bacteria alpha diversity indices (Chao1 richness estimator, Observed_species, Goods _Coverage, Shannon diversity index, and Simpson diversity index) were calculated by QIIME OTU tables [29]. Beta diversity analysis was performed based on the Bray–Curtis dissimilarity index (Bray and Curtis, 1957), Visualization was performed through principal coordinate analysis (PCoA) [30]. The relationships between soil environmental factor and soil microbial communities were analysed using redundancy analysis (RDA). CANOCO 5.0 software was used to extract the physicochemical characteristics which had the most decisive influence on microbial communities.

2.8. Data Analysis

Data compilation and computation were performed with Microsoft Excel 2016. DPS 9.01 was used for data analysis, and Duncan’s new multiple range test was used as the significance test for sample differences (α = 0.05). GraphPad Prism 8.4.2 was used to plot the data, and the Pearson correlation test in SPASS 26.0 was used for correlation analysis.

3. Results and Analyses

3.1. Effect of Applying Tomato Plant Residue Compost and PGPR on the Nutrient Content of Ginger Field Soil

As shown in Table 1, compared to CK, the TC, TC-BS, and TC-BA treatments significantly enhanced the AP content (increases of 19.54%, 31.09%, and 18.91%, respectively) and AK content (increases of 37.20%, 37.38%, and 18.78%, respectively) of ginger field soil. In addition, the TC and TC-BS treatments significantly enhanced the AN (increases of 21.66% and 11.05%, respectively) and TN content. Compared to CK, the TC treatment significantly increased the amount of SOM, while the TC-BS treatment significantly lowered the amount of TK and improved the EC of ginger field soil.

3.2. Effect of Applying Tomato Plant Residue Compost and PGPR on the Enzyme Activity of Ginger Field Soil

As shown in Figure 1, different treatment procedures had different effects on soil enzyme activities. Compared to CK, the TC and TC-BS treatments significantly increased soil urease activity, neutral phosphatase activity, and sucrase activities (TC treatment: 55.89%, 35.59%, and 57.27% increases in the activity of these three enzymes, respectively; TC-BS treatment: 29.57%, 27.03%, and 25.37% increases in activity, respectively). TC-BA only significantly increased the activity of sucrase. Compared to TC, the TC-BS and TC-BA treatments inhibited the activity of soil urease, neutral phosphatase, and sucrase. Thus, the effects of different treatments on the activity of the three soil enzymes followed the order of TC > TC-BS > TC-BA > CK.

3.3. Effect of Applying Tomato Plant Residue Compost and PGPR on the Alpha Diversity of Ginger Field Soil Bacteria

After chimera removal, a total of 249,467 high-quality target sequences were obtained from the four treatments. Sparse curves indicated the gradual flattening of the operational taxonomic unit count in the samples as the number of sequences increased (Figure 2), demonstrating that the amount of sequencing data was large enough to reflect the data of most species in the samples. For a comprehensive evaluation of the alpha diversity in microbial communities, the Chao1 index and Observed_species was selected to characterize the abundance in these communities, the Good’s coverage index was selected to characterize the coverage, while the Shannon index and Simpson index were chosen to characterize the diversity. As shown in Table 2, compared to CK and TC, the TC-BS treatment led to significantly increases in the Chao1 index, Observed_species, Shannon index, and Simpson index, while the TC-BA treatment significantly decreased the Chao1 index, Observed_species and Shannon index.

3.4. Effect of Applying Tomato Plant Residue Compost and PGPR on the Relative Abundance of Soil Bacteria in Ginger Field at the Phylum and Genus Level

Sequences in each operational taxonomic unit were analyzed at 97% similarity. It was found that 98.68% of the sequences belonged to the phylum level, and 34 bacterial phyla were identified. As shown in Figure 3a, the dominant bacterial phyla in the ginger field soil were Proteobacteria (35.53–40.45%), Actinobacteria (15.23–17.15%), Acidobacteria (14.52–15.91%), Chloroflexi (7.60–9.85%), Firmicutes (5.42–8.49%), and Gemmatimonadetes (3.60–5.26%). Compared to CK, the TC treatment increased the relative abundances of Chloroflexi and Gemmatimonadetes by 1.40% and 1.80%, respectively, and reduced the relative abundance of Firmicutes by 0.80%. The TC-BS treatment led to increases in the relative abundances of Proteobacteria, Acidobacteria, and Chloroflexi of 2.80%, 0.40%, and 1.30%, respectively, and a reduction in the relative abundance of Firmicutes of 2.90%. The TC-BA treatment had no significant influence on the relative abundances of bacterial phyla.
A total of 504 bacterial genera were identified by sequence analysis, as shown in Figure 3b. The top 10 bacterial genera accounted for about 25.00% of the total genus count. Other than the undefined genera, the dominant bacterial genera in the ginger field soil were Subgroup_6 (7.71–8.42%), Bacillus (2.33–4.11%), MND1 (2.64–3.44%), KD4-96 (1.69–2.15%), Skermanella (1.60–1.92%), and RB41 (1.39–1.75%). Compared to CK, the TC treatment increased the relative abundance of Bacillus by 0.68%; the TC-BS treatment increased the relative abundances of Subgroup_6, MND1, Bacillus, and Skermanella by 0.14%, 0.41%, 1.12%, and 0.30%, respectively; and the TC-BA treatment increased the relative abundances of the above genera by 0.51%, 0.43%, 0.59%, and 0.32%, respectively.

3.5. Principal Coordinate Analysis (PCoA) of the Ginger Field Soil Bacterial Community

PCoA based on Bray-Curtis dissimilarity metrics was used to compare the structural differences in bacterial communities across different treatments (Figure 4). The explained variances of samples on PCo1 and PCo2 were 19.3% and 14.3%, respectively. In the analysis results, each sample formed a cluster by itself on PCo1 and PCo2, indicating good reproducibility of the treatments. Samples from different treatments aggregated in four different regions of the plot, an indication of significant changes in the bacterial community structure of ginger field soil after the application of tomato plant residue compost and PGPR.

3.6. Redundancy Analysis (RDA) of the Soil Bacterial Community of Ginger Field Soil and Environmental Factors

RDA was applied to reveal the correlations between the community composition of ginger field soil bacteria at the phylum level and environmental factors (Figure 5). The bacterial communities were significantly affected by environmental factors. PCo1 and PCo2 was able to explain 50.55% and 20.36% of the variance seen in bacterial communities, respectively. By ranking the constraints in Canoco5, five environmental factors making the greatest contributions to the composition of bacterial communities were selected: TK (30.60%), pH (24.20%), AP (22.80%), AK (14.80%), and AN (12.40%). Proteobacteria and Actinobacteria, the dominant bacterial phyla, were positively correlated with pH, AP, and AK, and negatively correlated with AN and TK. Acidobacteria was positively correlated with TK and AN, and negatively correlated with AP and pH, while showing no correlation with AK. The above results showed that TK (p = 0.002), pH (p = 0.0012), and AP (p = 0.016) were the main driving forces behind the composition of bacterial communities in the ginger field soil.

4. Discussion

4.1. Effect of Applying Tomato Plant Residue Compost and PGPR on Ginger Field Soil Nutrient Content

Vegetable residue compost contains a large amount of cellulolytic bacteria. In the composting process, these bacteria decompose residue into nutrients that are easily absorbed by plants [31]. PGPR could inhibit pathogens by producing plant hormones, iron carriers, volatile organic compounds, and antibiotics [32,33], while accelerating the decomposition of organic substances and dissolving the phosphorus and potassium in soil to promote nutrient absorption by plants [34,35,36]. The results of this study confirmed the synergic interaction between vegetable residue compost and PGPR. The joint application of tomato plant residue compost and PGPR led to significantly increased levels of SOM, TN, AN, and AK in ginger field soil. However, the best effect was achieved when tomato plant residue compost was applied alone. Consistent results were obtained by Saqib et al. [37] in their effort to restore polluted soil using vegetable waste compost. In addition, compared to the application of tomato plant residue compost alone, or no application of tomato plant residue compost or PGPR, B. subtilis inoculation in soil supplemented with tomato plant residue compost increased the AP content by 9.66%–31.09%. These results were consistent with those obtained by Babalola [38], who reported that B. subtilis could dissolve bound phosphorus, mineralize organic phosphorus, and release soluble inorganic phosphate into soil by decomposing phosphate-rich organic compounds. Other than the potassium directly provided by the decomposition of vegetable residue, the increase in AK in ginger field soil may have originated from the transformation of mineralized potassium into free potassium by acid hydrolysis [39].

4.2. Effect of Applying Tomato Plant Residue Compost and PGPR on Ginger Field Soil Enzyme Activity

Soil enzymes exhibit rapid responses to stress [40]. Hydrolases are one of the two major enzyme families involved in the bioremediation of polluted soil [41]. The main representatives of hydrolases (i.e., urease, sucrase, and phosphatase) play important roles in the decomposition of exogenous organic matter [42]. In this study, the application of tomato plant residue compost and PGPR significantly increased the activity of these three enzymes in soil. Similar results have been obtained in a number of studies. For example, Chen et al. [43] showed that increasing crop residue application significantly improved the activity of soil sucrase, acid phosphatase, and urease in Loess Plateau soil. Asghar et al. [44] find that Trichoderma spp. RW309 inoculation in organic compost could significantly improve soil phosphatase activity. This was largely due to the increase in microorganism diversity in the ginger rhizosphere by PGPR, as the inducing compounds secreted by this class of enzymes could improve soil enzyme activity [45]. Vegetable residue compost, however, increases the SOM and humus levels and supplies soil enzymes with abundant binding sites and protective sites, thus enhancing their activity [46]. Lu et al. [47] found that Bacillus velezensis inoculation in tomato field soil significantly reduced soil urease activity, but had no significant effect on sucrase activity. Similar results were also obtained in the present study. Compared to the control, the inoculation of B. amyloliquefaciens had no significant effect on urease or phosphatase activity. However, compared to the application of tomato plant residue compost alone, this treatment significantly reduced soil urease activity, phosphatase activity, and sucrase activity, indicating a less-than-optimum response of soil enzyme activity to the combined application of tomato plant residue and PGPR.

4.3. Effect of Applying Tomato Plant Residue Compost and PGPR on the Ginger Field Soil Bacterial Community

A diverse bacterial community helps to promote the healthy and sustained growth of the soil ecosystem and is an indicator of soil health [48]. In the sand dunes of the Netherlands, rhizosphere soil bacteria possess more functional genes related to transport proteins, glycolysis, and hydrogen metabolism compared to non-rhizosphere soil bacteria [49]. In this study, tomato plant residue compost and PGPR were applied to ginger field soil and soil bacterial communities in the proximity of ginger roots were sequenced and analyzed using the Illumina MiSeq system (Shanghai Paiseno Biotechnology Co., Ltd. Shanghai, China). The results showed that the Chao1 index and Shannon index of ginger root soil increased after the application of tomato plant residue compost. Significant increases in these two bacterial diversity indices were also observed after B. subtilis inoculation. These results were consistent with those obtained by Du et al. [50], who reported that the addition of organic fertilizers or bio-fertilizer was beneficial to soil fertility, crop growth, and microbial diversity, and that these fertilizers helped to enrich the amounts of Bacillus and Clostridium bacteria in walnut orchard soil, while reducing the number of Fusarium bacteria. Tomato plant residue compost is rich in nutrients such as nitrogen, phosphorus, and potassium [51]. B. subtilis contains a large quantity of organic substances, such as amino acids and sugars. The active strains of B. subtilis also secrete bioactive factors such as growth-promoting hormones after they have colonized the soil, stimulating plant root secretion [52] and enhancing the proliferation of beneficial soil bacteria.
The spores of B. subtilis and their multi-layer membranes allow for the long-term survival of bacteria [53]. Due to the presence of the 16S rRNA gene, Proteobacteria, Actinobacteria, and Acidobacteria are the most abundant bacterial phyla in the soil of coniferous forest, shrub grassland, and tropical forest ecosystems [54]. In the present study, it was found that B. subtilis inoculation in soil following the application of tomato plant residue compost significantly increased the relative abundance of dominant bacterial phyla (Proteobacteria, Acidobacteria, and Chloroflexi) and dominant bacterial genera (Subgroup_6, Bacillus, and MND1). These results are similar to the findings of Sui et al. [55]. The inoculation of B. amyloliquefaciens SQR9, however, had no such noticeable effect on the bacterial diversity and species abundance of ginger field soil, possibly as a result of bacterial antagonism and competition. The antibiotics, secondary metabolites, and degradative enzymes released by Actinobacteria may have an active effect on soil microbiota by inhibiting the growth of some soil microorganisms, including plant pathogens [17]. Wei et al. [56] noticed the increased abundance of Actinobacteria after returning vegetable residue to the field. Similar results were also observed in this study. In contrast, no significant change in Actinobacteria abundance was observed after PGPR inoculation.
Soil environmental factors either directly or indirectly affect the structure of the soil bacterial community. Xun et al. [57] have suggested that soil properties, rather than the number of microorganisms inoculated, determine the composition and function of these microorganisms, and that soil pH is the dominant factor behind changes in bacterial community structure. The results of RDA in the present study confirmed these observations. After the application of tomato plant residue compost and PGPR, the pH, TK, and AP were identified as the main driving factors of bacterial community composition in ginger field soil.

5. Conclusions

Compared to CK, the TC and TC-BS treatment significantly increased the level of SOM, AN, AP, AK, and TN, increased soil urease activity, neutral phosphatase activity, and sucrase activity, and enhanced the relative abundances of the phylum Chloroflexi, the phylum Gemmatimonadetes, and the genus Bacillus, while decreasing the relative abundance of Firmicutes. Compared to the TC treatment, the TC-BS and TC-BA treatments had no significant effects on soil nutrients and enzyme activity, but TC-BS significantly improved the diversity of soil bacteria, the beneficial microorganisms, Proteobacteria, Acidobacteria, Chloroflexi, and Bacillus, were dominant in all soil samples. PCoA revealed significant differences in bacterial community structure across different treatments. RDA indicated that TK (p = 0.002), pH (p = 0.0012), and AP (p = 0.016) were the main driving factors of bacterial community composition in ginger field soil.
In conclusion, the high-temperature composting and fermentation of tomato plant residue and its return to the field is a simple and economical way to improve the soil quality of ginger fields. This method effectively reduces the waste of tomato plant residue as a resource, and helps to address continuous cropping obstacle in ginger field soil such as the decrease of soil fertility. The synergic application of tomato plant residue compost and PGPR enhances the relative abundance of beneficial microorganisms in the soil, reduces the occurrence of soil-borne diseases, and helps to maintain a healthy ginger rhizosphere.

Author Contributions

Conceptualization, C.H. and S.C.; methodology and software, C.H., K.X. and A.S.; validation and formal Analysis, C.H. and K.X.; investigation, K.X. and R.C.; resources, C.H. and K.X.; data curation, K.X.; writing—original draft preparation, K.X.; writing—review and editing, C.H., S.C., M.S., Q.D. and D.J.; visualization, K.X.; supervision, C.H. and S.C.; project administration, C.H. and S.C.; funding acquisition, C.H., Y.L. and X.Y. All authors have read and agreed to the published version of the manuscript.

Funding

This research was supported by the Modern Agro-industry Technology Research System (Grant Number CARS-24-B-04), the Central Public-interest Scientific Institution Basal Research Fund (No. IVF-BRF2022009), and the National Natural Science Foundation of China (31872092).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data are contained within the article.

Acknowledgments

This research acknowledged the supports of The Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, the Ministry of Agriculture, China.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Han, L.; Li, Y.S.; Yu, X.C.; He, C.X. Effects of vegetable residue compost returning to soil on soil properties and vegetable yield in solar greenhouse. Chin. J. Appl. Ecol. 2016, 27, 1553–1559. [Google Scholar] [CrossRef]
  2. Wang, R.; Zhao, Y.; Xie, X.; Mohamed, T.A.; Zhu, L.; Tang, Y.; Chen, Y.; Wei, Z. Role of NH3 recycling on nitrogen fractions during sludge composting. Bioresour. Technol. 2020, 295, 122175. [Google Scholar] [CrossRef] [PubMed]
  3. Meena, R.S.; Meena, V.S.; Meena, S.K.; Verma, J.P. The needs of healthy soils for a healthy world. J. Clean. Prod. 2015, 102, 560–561. [Google Scholar] [CrossRef]
  4. Kianpoor Kalkhajeh, Y.; Huang, B.; Hu, W.; Ma, C.; Gao, H.; Thompson, M.L.; Bruun Hansen, H.C. Environmental soil quality and vegetable safety under current greenhouse vegetable production management in China. Agric. Ecosyst. Environ. 2021, 307, 107230. [Google Scholar] [CrossRef]
  5. Fernández-Gómez, M.J.; Romero, E.; Nogales, R. Feasibility of vermicomposting for vegetable greenhouse waste recycling. Bioresour. Technol. 2010, 101, 9654–9660. [Google Scholar] [CrossRef] [PubMed]
  6. Sokol, N.W.; Slessarev, E.; Marschmann, G.L.; Nicolas, A.; Blazewicz, S.J.; Brodie, E.L.; Firestone, M.K.; Foley, M.M.; Hestrin, R.; Hungate, B.A.; et al. Life and death in the soil microbiome: How ecological processes influence biogeochemistry. Nat. Rev. Microbiol. 2022, 20, 415–430. [Google Scholar] [CrossRef] [PubMed]
  7. Postma-Blaauw, M.B.; de Goede, R.G.; Bloem, J.; Faber, J.H.; Brussaard, L. Soil biota community structure and abundance under agricultural intensification and extensification. Ecology 2010, 91, 460–473. [Google Scholar] [CrossRef]
  8. Zhao, S.; Li, K.; Zhou, W.; Qiu, S.; Huang, S.; He, P. Changes in soil microbial community, enzyme activities and organic matter fractions under long-term straw return in north-central China. Agric. Ecosyst. Environ. 2016, 216, 82–88. [Google Scholar] [CrossRef]
  9. Ai, C.; Liang, G.; Sun, J.; Wang, X.; Zhou, W. Responses of extracellular enzyme activities and microbial community in both the rhizosphere and bulk soil to long-term fertilization practices in a fluvo-aquic soil. Geoderma 2012, 173–174, 330–338. [Google Scholar] [CrossRef]
  10. Navarro-Noya, Y.E.; Gómez-Acata, S.; Montoya-Ciriaco, N.; Rojas-Valdez, A.; Suárez-Arriaga, M.C.; Valenzuela-Encinas, C.; Jiménez-Bueno, N.; Verhulst, N.; Govaerts, B.; Dendooven, L. Relative impacts of tillage, residue management and crop-rotation on soil bacterial communities in a semi-arid agroecosystem. Soil Biol. Biochem. 2013, 65, 86–95. [Google Scholar] [CrossRef]
  11. Meng, F.; Dungait, J.A.J.; Xu, X.; Bol, R.; Zhang, X.; Wu, W. Coupled incorporation of maize (Zea mays L.) straw with nitrogen fertilizer increased soil organic carbon in Fluvic Cambisol. Geoderma 2017, 304, 19–27. [Google Scholar] [CrossRef]
  12. Kong, P.J.; Zheng, J.; Luan, L.; Chen, Z.Y.; Xue, J.R.; Sun, B.; Jiang, Y.J. Effects of Different Types of Straw Returning on the Bacterial Community, Organic Carbon Mineralization and Maize Yield in Upland Red Soil. Environ. Sci. 2021, 42, 6047–6057. (In Chinese) [Google Scholar] [CrossRef]
  13. Olasupo, I.O.; Liang, Q.; Zhang, C.; Islam, M.S.; Li, Y.; Yu, X.; He, C. Agronomic Biofortification of Cayenne Pepper Cultivars with Plant Growth-Promoting Rhizobacteria and Chili Residue in a Chinese Solar Greenhouse. Microorganisms 2021, 9, 2398. [Google Scholar] [CrossRef] [PubMed]
  14. Gray, E.J.; Smith, D.L. Intracellular and extracellular PGPR: Commonalities and distinctions in the plant-bacterium signaling processes. Soil Biol. Biochem. 2005, 37, 395–412. [Google Scholar] [CrossRef]
  15. Senkovs, M.; Nikolajeva, V.; Makarenkova, G.; Petrina, Z. Influence of Trichoderma asperellum and Bacillus subtilis as biocontrol and plant growth promoting agents on soil microbiota. Ann. Microbiol. 2021, 71, 34. [Google Scholar] [CrossRef]
  16. Miljaković, D.; Marinković, J.; Balešević-Tubić, S. The Significance of Bacillus spp. in Disease Suppression and Growth Promotion of Field and Vegetable Crops. Microorganisms 2020, 8, 1037. [Google Scholar] [CrossRef]
  17. Kaspar, F.; Neubauer, P.; Gimpel, M. Bioactive Secondary Metabolites from Bacillus subtilis: A Comprehensive Review. J. Nat. Prod. 2019, 82, 2038–2053. [Google Scholar] [CrossRef]
  18. Lu, Y.F.; Xu, H.; Duan, H.T.; Mei, X.L.; Li, R.; Guan, X.J.; Zhang, N.; Shen, Q.R. Foliar Spraying of Liquid Compound Microbial Fertilizer Containing Bacillus amyloliquefaciens SQR9 Promoted Plant Foliar Spraying of Liquid Compound Microbial Fertilizer Containing Bacillus amyloliquefaciens SQR9 Promoted Plant Growth. Soils 2019, 51, 903–909. (In Chinese) [Google Scholar] [CrossRef]
  19. Zhao, W.; Guo, Q.; Li, S.; Wang, P.; Dong, L.; Su, Z.; Zhang, X.; Lu, X.; Ma, P. Effects of Bacillus subtilis NCD-2 and broccoli residues return on potato Verticillium wilt and soil fungal community structure. Biol. Control. 2021, 159, 104628. [Google Scholar] [CrossRef]
  20. Hui, C.; Sun, P.; Guo, X.; Jiang, H.; Zhao, Y.; Xu, L. Shifts in microbial community structure and soil nitrogen mineralization following short-term soil amendment with the ammonifier Bacillus amyloliquefaciens DT. Int. Biodeterior. Biodegrad. 2018, 132, 40–48. [Google Scholar] [CrossRef]
  21. Huang, X.F.; Zhou, D.; Guo, J.; Manter, D.K.; Reardon, K.F.; Vivanco, J.M. Bacillus spp. from rainforest soil promote plant growth under limited nitrogen conditions. J. Appl. Microbiol. 2015, 118, 672–684. [Google Scholar] [CrossRef] [PubMed]
  22. Li, H.; Qiu, Y.; Yao, T.; Ma, Y.; Zhang, H.; Yang, X. Effects of PGPR microbial inoculants on the growth and soil properties of Avena sativa, Medicago sativa, and Cucumis sativus seedlings. Soil Tillage Res. 2020, 199, 104577. [Google Scholar] [CrossRef]
  23. Pane, C.; Celano, G.; Piccolo, A.; Villecco, D.; Spaccini, R.; Palese, A.M.; Zaccardelli, M. Effects of on-farm composted tomato residues on soil biological activity and yields in a tomato cropping system. Chem. Biol. Technol. Agric. 2015, 2, 4. [Google Scholar] [CrossRef] [Green Version]
  24. Ghaly, A.E.; Alkoaik, F.; Snow, A. Inactivation of Botrytis cinerea during thermophilic composting of greenhouse tomato plant residues. Appl. Biochem. Biotechnol. 2006, 133, 59–75. [Google Scholar] [CrossRef]
  25. Bao, S.D. Analysis Method of Soil and Agricultural Chemistry, 3rd ed.; China Agricultural Press: Beijing, China, 2000; pp. 25–108. [Google Scholar]
  26. Guan, S.Y. Soil Enzyme and Its Study Method; China Agriculture Press: Beijing, China, 1986; pp. 270–285. [Google Scholar]
  27. Liu, Z.; Xie, W.; Yang, Z.; Huang, X.; Zhou, H. Effects of Manure and Chemical Fertilizer on Bacterial Community Structure and Soil Enzyme Activities in North China. Agronomy 2021, 11, 1017. [Google Scholar] [CrossRef]
  28. Zhang, X.; Tian, X.; Ma, L.; Feng, B.; Liu, Q.; Yuan, L.; Fan, C.; Huang, H.; Huang, H.; Yang, Q. Biodiversity of the Symbiotic Bacteria Associated with Toxic Marine Dinoflagellate Alexandrium tamarense. J. Biosci. Med. 2015, 3, 23–28. [Google Scholar] [CrossRef] [Green Version]
  29. Lozupone, C.; Knight, R. UniFrac: A New Phylogenetic Method for Comparing Microbial Communities. Appl. Environ. Microbiol. 2005, 72, 8228–8235. [Google Scholar] [CrossRef] [Green Version]
  30. Ramette, A. Multivariate analyses in microbial ecology. FEMS Microbiol. Ecol. 2007, 62, 142–160. [Google Scholar] [CrossRef] [Green Version]
  31. Kong, T.; Li, B.; Ke, Y.; Zhu, H.Y.; Ma, Y.; Han, Y.N.; Li, J.F.; Wen, J.F.; Zhang, X. Effect of vegetables waste compost on protected vegetable yield and soil microbial property. Soil Fertil. Sci. China 2017, 5, 157–160. (In Chinese) [Google Scholar] [CrossRef]
  32. Tabassum, B.; Khan, A.; Tariq, M.; Ramzan, M.; Iqbal Khan, M.S.; Shahid, N.; Aaliya, K. Bottlenecks in commercialisation and future prospects of PGPR. Appl. Soil Ecol. 2017, 121, 102–117. [Google Scholar] [CrossRef]
  33. Sánchez, Ó.J.; Ospina, D.A.; Montoya, S. Compost supplementation with nutrients and microorganisms in composting process. Waste Manag. 2017, 69, 136–153. [Google Scholar] [CrossRef] [PubMed]
  34. Tanwar, A.; Aggarwal, A.; Parkash, V. Effect of bioinoculants and superphosphate fertilizer on the growth and yield of broccoli (Brassicaoleracea L. var italica Plenck). N. Z. J. Crop Hortic. Sci. 2014, 42, 288–302. [Google Scholar] [CrossRef] [Green Version]
  35. Yildirim, E.; Karlidag, H.; Turan, M. Growth, Nutrient Uptake, and Yield Promotion of Broccoli by Plant Growth Promoting Rhizobacteria with Manure. HortsSience 2011, 46, 932–936. [Google Scholar] [CrossRef] [Green Version]
  36. Liu, X. Application of microbial fertilizer in agricultural production. Agric. Henan 2021, 17, 14–15. (In Chinese) [Google Scholar] [CrossRef]
  37. Bashir, S.; Bakhsh Gulshan, A.; Iqbal, J.; Husain, A.; Alwahibi, M.S.; Alkahtani, J.; Dwiningsih, Y.; Bakhsh, A.; Ahmed, N.; Jamal Khan, M.; et al. Comparative role of animal manure and vegetable waste induced compost for polluted soil restoration and maize growth. Saudi J. Biol. Sci. 2021, 28, 2534–2539. [Google Scholar] [CrossRef]
  38. Babalola, O.O. Beneficial bacteria of agricultural importance. Biotechnol. Lett. 2010, 32, 1559–1570. [Google Scholar] [CrossRef]
  39. Sheng, X.F.; He, L.Y. Solubilization of potassium-bearing minerals by a wild-type strain of Bacillus edaphicus and its mutants and increased potassium uptake by wheat. Saudi J. Biol. Sci. 2006, 52, 66–72. [Google Scholar] [CrossRef]
  40. Du, J.; Hou, F.; Zhou, Q. Response of soil enzyme activity and soil bacterial community to PCB dissipation across different soils. Chemosphere 2021, 283, 131229. [Google Scholar] [CrossRef]
  41. Paz-Ferreiro, J.; Trasar-Cepeda, C.; Leirós, M.C.; Seoane, S.; Gil-Sotres, F. Biochemical properties in managed grassland soils in a temperate humid zone: Modifications of soil quality as a consequence of intensive grassland use. Biol. Fertil. Soils 2009, 45, 711–722. [Google Scholar] [CrossRef] [Green Version]
  42. Lee, S.; Xiong, J.; Ru, S.; Patil, S.M.; Kurade, M.B.; Govindwar, S.P.; Oh, S.; Jeon, B. Toxicity of benzophenone-3 and its biodegradation in a freshwater microalga Scenedesmus obliquus. J. Hazard. Mater. 2020, 389, 122149. [Google Scholar] [CrossRef]
  43. Chen, H.; Liang, Q.; Gong, Y.; Kuzyakov, Y.; Fan, M.; Plante, A.F. Reduced tillage and increased residue retention increase enzyme activity and carbon and nitrogen concentrations in soil particle size fractions in a long-term field experiment on Loess Plateau in China. Soil Tillage Res. 2019, 194, 104296. [Google Scholar] [CrossRef]
  44. Asghar, W.; Kataoka, R. Effect of co-application of Trichoderma spp. with organic composts on plant growth enhancement, soil enzymes and fungal community in soil. Arch. Microbiol. 2021, 203, 4281–4291. [Google Scholar] [CrossRef]
  45. Ning, C.C.; Wang, J.H.; Cai, K.Z. The Effects of Organic Fertilizers on Soil Fertility and Soil Environmental Quality: A Review. Ecol. Environ. Sci. 2016, 25, 175–181. (In Chinese) [Google Scholar] [CrossRef]
  46. Pascual, J.A.; García, C.; Hernandez, T. Lasting microbiological and biochemical effects of the addition of municipal solid waste. Arid. Soil. Biol. Fertil. Soils 1999, 30, 1–6. [Google Scholar] [CrossRef]
  47. Lu, K.Z.; Jin, Q.; Cao, Q.; Li, S.S.; Sun, S.; Jiang, Q.Y.; JIin, J.R.; Ling, L.C.; Fu, X.H.; Du, X.; et al. Effects of different microbial agents on tomato quality and soil enzyme activity. J. Shanghai Norm. Univ. Nat. Sci. 2019, 48, 197–206. (In Chinese) [Google Scholar] [CrossRef]
  48. Li, J.H.; Gao, K.X.; Wan, L.; Cao, G.Y.; Jiao, F.Y.; Wang, Y.P.; Tian, Y.H.; Zhao, B.J.; Li, C.R. Effects of microbial agent on the growth of Catalpa bungei seedlings and the diversity of bacterial community in rhizosphere soil. Acta Ecol. Sin. 2020, 40, 7588–7607. (In Chinese) [Google Scholar] [CrossRef]
  49. Yan, Y.; Kuramae, E.E.; de Hollander, M.; Klinkhamer, P.G.; van Veen, J.A. Functional traits dominate the diversity-related selection of bacterial communities in the rhizosphere. ISME J. 2017, 11, 56–66. [Google Scholar] [CrossRef] [Green Version]
  50. Du, T.; He, H.; Zhang, Q.; Lu, L.; Mao, W.; Zhai, M. Positive effects of organic fertilizers and biofertilizers on soil microbial community composition and walnut yield. Appl. Soil Ecol. 2022, 175, 104457. [Google Scholar] [CrossRef]
  51. Olasupo, I.O.; Wang, J.; Wei, X.; Sun, M.; Li, Y.; Yu, X.; Yan, Y.; He, C. Chili residue and Bacillus laterosporus synergy impacts soil bacterial microbiome and agronomic performance of leaf mustard (Brassica juncea L.) in a solar greenhouse. Plant Soil 2022. [Google Scholar] [CrossRef]
  52. Song, Y.L.; Yu, J.; Chen, S.G.; Xiao, C.Z.; Li, Y.H.; Su, X.R.; Ding, F.J. Effects of Complex Microbial Agent on Cotton Physiological Characteristics, Microorganism and Physicochemical Properties in Rhizosphere Soil. Soils 2019, 51, 477–487. (In Chinese) [Google Scholar] [CrossRef]
  53. McKenney, P.T.; Driks, A.; Eichenberger, P. The Bacillus subtilis endospore: Assembly and functions of the multilayered coat. Nat. Rev. Microbiol. 2013, 11, 33–44. [Google Scholar] [CrossRef] [PubMed]
  54. Delgado-Baquerizo, M.; Oliverio, A.M.; Brewer, T.E.; Benavent-González, A. A global atlas of the dominant bacteria found in soil. Science 2018, 359, 320–325. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  55. Sui, J.; Ji, C.; Wang, X.; Liu, Z.; Sa, R.; Hu, Y.; Wang, C.; Li, Q.; Liu, X. A plant growth-promoting bacterium alters the microbial community of continuous cropping poplar trees’ rhizosphere. J. Appl. Microbiol. 2019, 126, 1209–1220. [Google Scholar] [CrossRef]
  56. Wei, X.; Li, Y.; Fan, X.; He, C.; Yan, Y.; Sun, M.; Ding, C.; Wang, J.; Yu, X. Techno-Economic Feasibility of In Situ Vegetable Residue Return in the Chinese Solar Greenhouse. Agronomy 2021, 11, 1828. [Google Scholar] [CrossRef]
  57. Xun, W.; Huang, T.; Zhao, J.; Ran, W.; Wang, B.; Shen, Q.; Zhang, R. Environmental conditions rather than microbial inoculum composition determine the bacterial composition, microbial biomass and enzymatic activity of reconstructed soil microbial communities. Soil Biol. Biochem. 2015, 90, 10–18. [Google Scholar] [CrossRef]
Agronomy 12 01741 g001 550
Figure 1. Effect of applying tomato plant residue compost and PGPR on the enzyme activity of ginger field soil. CK: no tomato plant residue compost or PGPR; TC: tomato plant residue compost; TC-BS: tomato plant residue compost +B. subtilis; TC-BA: tomato plant residue compost +B. amyloliquefaciens SQR9. (a) Urease activity (mg NH3-N/g·24 h); (b) neutral phosphatase activity (mg Phenol/g·24 h); (c) sucrase activity (mg Glucose/g·24 h), (different letters indicate significant difference, Duncan’s new complex range method, n = 3, p < 0.05).
Figure 1. Effect of applying tomato plant residue compost and PGPR on the enzyme activity of ginger field soil. CK: no tomato plant residue compost or PGPR; TC: tomato plant residue compost; TC-BS: tomato plant residue compost +B. subtilis; TC-BA: tomato plant residue compost +B. amyloliquefaciens SQR9. (a) Urease activity (mg NH3-N/g·24 h); (b) neutral phosphatase activity (mg Phenol/g·24 h); (c) sucrase activity (mg Glucose/g·24 h), (different letters indicate significant difference, Duncan’s new complex range method, n = 3, p < 0.05).
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Figure 2. Sparse graph of each sample. CK: no tomato plant residue compost or PGPR; TC: tomato plant residue compost; TC-BS: tomato plant residue compost +B. subtilis; TC-BA: tomato plant residue compost +B. amyloliquefaciens SQR9.
Figure 2. Sparse graph of each sample. CK: no tomato plant residue compost or PGPR; TC: tomato plant residue compost; TC-BS: tomato plant residue compost +B. subtilis; TC-BA: tomato plant residue compost +B. amyloliquefaciens SQR9.
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Agronomy 12 01741 g003a 550Agronomy 12 01741 g003b 550
Figure 3. Relative abundance of soil bacteria in ginger field at the phylum and genus level. [(a) for phylum level; (b) for genus level]. CK: no tomato plant residue compost or PGPR; TC: tomato plant residue compost; TC-BS: tomato plant residue compost +B. subtilis; TC-BA: tomato plant residue compost + B. amyloliquefaciens SQR9.
Figure 3. Relative abundance of soil bacteria in ginger field at the phylum and genus level. [(a) for phylum level; (b) for genus level]. CK: no tomato plant residue compost or PGPR; TC: tomato plant residue compost; TC-BS: tomato plant residue compost +B. subtilis; TC-BA: tomato plant residue compost + B. amyloliquefaciens SQR9.
Agronomy 12 01741 g003aAgronomy 12 01741 g003b
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Figure 4. Principal coordinate analysis (PCoA) of the ginger field soil bacterial community.
Figure 4. Principal coordinate analysis (PCoA) of the ginger field soil bacterial community.
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Figure 5. Redundancy analysis (RDA) of the soil bacterial community of ginger field soil and environmental factors.
Figure 5. Redundancy analysis (RDA) of the soil bacterial community of ginger field soil and environmental factors.
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Table
Table 1. Effect of applying tomato plant residue compost and PGPR on the nutrient content of ginger field soil.
Table 1. Effect of applying tomato plant residue compost and PGPR on the nutrient content of ginger field soil.
TreatmentsSOM
g/kg		TN
%		TP
%		TK
%		AN
mg/kg		AP
mg/kg		AK
mg/kg		pHEC
us/cm
CK33.43 ± 1.33 b0.16 ± 0.01 b0.17 ± 0.01 a1.86 ± 0.07 a137.00 ± 2.00 c158.67 ± 6.66 c381.67 ± 6.51 c7.2 ± 0.01 a120.00 ± 0.01 b
TC39.23 ± 3.06 a0.19 ± 0.01 a0.18 ± 0.01 a1.80 ± 0.23 a166.67 ± 6.51 a189.67 ± 4.62 b523.67 ± 18.18 a7.2 ± 0.02 a123.33 ± 1.15 ab
TC-BS36.33 ± 0.85 ab0.18 ± 0.01 a0.18 ± 0.01 a1.51 ± 0.16 b152.00 ± 1.00 b208.00 ± 8.54 a524.33 ± 28.01 a7.3 ± 0.01 a130.33 ± 4.51 a
TC-BA34.43 ± 0.78 b0.16 ± 0.01 b0.17 ± 0.01 a1.78 ± 0.09 a137.67 ± 1.53 c188.67 ± 5.78 b453.33 ± 22.37 b7.3 ± 0.01 a126.67 ± 4.93 b
Note: CK: no tomato plant residue compost or PGPR; TC: tomato plant residue compost; TC-BS: tomato plant residue compost +B. subtilis; TC-BA: tomato plant residue compost +B. amyloliquefaciens SQR9. (Average ± standard deviation, n = 3. The different letters in the same column indicate significant differences at level of p < 0.05).
Table
Table 2. Effect of applying tomato plant residue compost and PGPR on the alpha diversity of ginger field soil bacteria.
Table 2. Effect of applying tomato plant residue compost and PGPR on the alpha diversity of ginger field soil bacteria.
TreatmentsEffective Sequence NumberChao1 IndexShannon IndexSimpson IndexObserved_SpeciesGoods_Coverage
CK612825561.30 ± 581.21 b10.96 ± 0.10 b0.9988 ± 0.00 b4406.63 ± 324.11 b0.95 ± 0.01 a
TC587455891.18 ± 86.66 b10.98 ± 0.04 b0.9988 ± 0.00 b4539.30 ± 61.51 b0.95 ± 0.00 a
TC-BS905487446.96 ± 250.02 a11.43 ± 0.02 a0.9992 ± 0.00 a5590.23 ± 107.54 a0.96 ± 0.00 a
TC-BA388854162.51 ± 50.14 c10.69 ± 0.06 c0.9986 ± 0.00 b3609.3± 54.23 c0.95 ± 0.00 a
Note: The different letters in the same column indicate significant differences at level of p < 0.05.
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Xie, K.; Sun, M.; Shi, A.; Di, Q.; Chen, R.; Jin, D.; Li, Y.; Yu, X.; Chen, S.; He, C. The Application of Tomato Plant Residue Compost and Plant Growth-Promoting Rhizobacteria Improves Soil Quality and Enhances the Ginger Field Soil Bacterial Community. Agronomy 2022, 12, 1741. https://doi.org/10.3390/agronomy12081741

AMA Style

Xie K, Sun M, Shi A, Di Q, Chen R, Jin D, Li Y, Yu X, Chen S, He C. The Application of Tomato Plant Residue Compost and Plant Growth-Promoting Rhizobacteria Improves Soil Quality and Enhances the Ginger Field Soil Bacterial Community. Agronomy. 2022; 12(8):1741. https://doi.org/10.3390/agronomy12081741

Chicago/Turabian Style

Xie, Kunhao, Mintao Sun, Aokun Shi, Qinghua Di, Ru Chen, Duo Jin, Yansu Li, Xianchang Yu, Shuangchen Chen, and Chaoxing He. 2022. "The Application of Tomato Plant Residue Compost and Plant Growth-Promoting Rhizobacteria Improves Soil Quality and Enhances the Ginger Field Soil Bacterial Community" Agronomy 12, no. 8: 1741. https://doi.org/10.3390/agronomy12081741

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