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Article

Diversity of the Soil Bacterial Community of Abandoned Jujube Land in the Loess Area of Northern Shaanxi in Different Years

by
Ning Ai
1,
Menghuan Zou
1,
Xuejiao Yu
2 and
Jie Gao
1,*
1
Key Laboratory of Applied Ecology on the Loess Plateau of Shaanxi Higher Education Institutions, College of Life Sciences, Yan’an University, Yan’an 716000, China
2
Institute of Scientific and Technical Information of China, Beijing 100038, China
*
Author to whom correspondence should be addressed.
Diversity 2025, 17(7), 462; https://doi.org/10.3390/d17070462
Submission received: 27 April 2025 / Revised: 28 June 2025 / Accepted: 28 June 2025 / Published: 30 June 2025
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Abstract

This research aimed to study changes in the diversity of the soil bacterial community in a jujube forest with different years of abandonment. To this end, we took the mountain jujube forest with different abandoned years (1 a, 3 a, 6a and 20 a) in the Qijiashan jujube experimental demonstration base in Yanchuan County as the research object; we used Illumina Miseq high-throughput sequencing technology to analyze the changes in the soil bacterial community structure and reveal the key environmental drivers of bacterial community variation in the abandoned jujube forest in the study area. The results showed the following findings: (1) Phylum Actinomycetota (34%), Proteobacteria (29%), and Acidobacteriota (13%) were the dominant phyla of the soil bacterial community in the abandoned jujube forest. (2) Abandonment altered the composition of soil bacteria at the OTU level in jujube plantations. (3) There are differences in the soil bacterial community structure across different periods of abandonment in the jujube forest. (4) Soil water content is the main factor affecting the bacterial community structure of the abandoned jujube forest. There are differences in the soil water content of abandoned woodlands, which affects the community structure of soil microorganisms.

1. Introduction

Soil microorganisms play an important role in ecosystems [1] and are the key factors affecting soil quality [2] and soil fertility [3]. Soil microorganisms interact with water and minerals in the soil to recycle nutrients and support plant growth [4], while soil microorganisms decompose organic organisms into inorganic forms of carbon, nitrogen, phosphorus, and other nutrients required for plant growth [5]. Studies have shown that the relationship between the microbial community’s structure and function has widespread effects on the biogeochemical cycle in the environment [6]. The strong influence of plant roots on microbial community structure may be due to the quantity and quality of plant carbon and nitrogen released from roots to the surrounding soil. The chemical diversity components of root exudates enrich specific microorganisms by stimulating the growth of specific microorganisms or inducing or inhibiting specific microbial functions. These specific microbial functions play an important role in the interactions between plants and microorganisms [7,8,9,10]. Changes in rhizosphere soil microorganisms affect the absorption and transformation of soil nutrients [11,12,13]. Therefore, the number and species of rhizosphere soil microorganisms are important factors affecting plant growth, development, and health [14]. Bacteria are important decomposition agents in soil, and their community structure and diversity play an important role in ecosystem balance [15]. Yu et al. showed that litter input reduced the population of soil carbon-fixing microorganisms but increased their community diversity and affected the community structure of soil carbon-fixing microorganisms [16]. Wang et al. also showed that soil microbial diversity was positively correlated with soil litter content [17]. Based on the response of the soil microbial diversity of artificial grassland in the Yellow River source to planting years, Sun et al. proposed that the restoration and succession of artificial grassland were beneficial to the restoration of microbial diversity, but the restoration of the soil microbial diversity of artificial grassland would take longer [18]. Studies have shown that the main environmental factors affecting soil microbial functional diversity include soil organic carbon, soil total nitrogen, and soil pH [19,20]. Bian et al. suggested that the number of soil microbial communities was significantly correlated with soil physical and chemical factors [21]. Yang et al. proposed that soil total phosphorus, soil available phosphorus, and soil bulk density were the main factors affecting the soil bacterial community structure in different vegetation types [22]. Wu et al. showed that land abandonment significantly influenced multiple microbial attributes and profoundly enhanced the microbial functional adaptation [23].
At present, many scholars focus on the effects of planting patterns [24,25,26,27,28], fertilization, soil types [29,30], and vegetation types on soil microorganisms, but there are few studies on the effects of abandonment on the soil microbial community structure. Abandonment is not only a waste of land resources but also affects farmers’ income and the ecological environment. The related research on the soil biology and soil properties of abandoned land has important practical significance for the development and utilization of abandoned land and scientific guidance regarding agricultural production practice [31]. Therefore, in this study, soil bacteria in jujube forests with different abandonment years were selected as the research objects, and Illumina Miseq high-throughput sequencing technology was used to analyze the changes in the soil bacterial community structure, with the aims of clarifying the composition and diversity of the soil bacterial community in jujube forests with different abandonment years, exploring the effect of abandonment on the bacterial community structure in jujube forests, and revealing the relationships between the soil bacterial community in jujube forests and soil environmental factors. We aimed to provide data-related support and a scientific basis for the future development and utilization of abandoned jujube forest land, as well as improving its quality and efficiency, in the Loess area of northern Shaanxi.

2. Materials and Methods

2.1. Study Area Overview and Formation Mechanisms of Abandoned Land

The study area is located in the Qijiashan jujube experimental demonstration base (36°57′ N, 110°29′ E, average altitude: 880 m) in Yanchuan County. The topography is a typical gully region of the Loess plateau in northern Shaanxi, with complex topography and vertical and horizontal gullies. This region has a temperate continental monsoon climate, with annual average precipitation of about 500 mm. The spatial and temporal distribution of rainfall is uneven, mainly concentrated in July–September, mostly comprising short-term heavy rainfall. The average annual temperature of the study area was 10.8 °C, the frost-free period was 183 d, and there were 6.99 h of sunshine. Soil erosion resistance is poor, and soil erosion is serious.
As an important economic tree species on the Loess Plateau, jujube forests are widely distributed in the study area. However, over the past three decades, rapid socioeconomic development has driven rural-to-urban migration. Coupled with declining economic returns from jujube land in recent years, an increasing number of farmers in the study area have abandoned the management of jujube land, leaving it to grow unmanaged. This has led to overgrown weeds, a loss of economic value, and ultimately the formation of extensive abandoned jujube land. Thus, the term “abandoned land” in this study specifically refers to this unmanaged jujube land.

2.2. Sample Collection

In September 2019, according to the principles of typicality and representativeness, the research group selected fixed sample plots of red jujube with different abandonment years for investigation and sampling in Qijiashan red jujube experimental base in Yanchuan County, Shaanxi Province. Detailed information about the sample plots is shown in Table 1 and a map of the research area is provided in another study [32].
Three sampling points were randomly selected from four fixed plots, and five 10 cm × 10 cm quadrats were selected for each sampling point according to the five-point sampling method, allowing us to collect the soil in the 0–10 cm soil layer. Then, the 15 soil samples from each sample plot were mixed evenly and weighed to 1 kg through a 2 mm sieve, before being divided into two parts. One part was loaded into a sealed sterile bag and put into an ice box for transportation to the laboratory; it was stored at −70 °C for DNA extraction. The second portion was put into a plastic bag and brought back to the laboratory at room temperature. After air drying, it was used for the determination of soil physicochemical properties. The methods used in this investigation were similar to those described in [33].

2.3. Experimental Method

The “ring-cutting and water immersion” method was used to measure and calculate the soil bulk density (BD), field capacity (FC), capillary water holding capacity (CWHC) and total capillary porosity (TV) [34]. The volume percentage of the soil particle size was measured using a laser particle size analyzer (with the soil particle size classification according to the American soil texture classification standard). The pH value was measured using a PHS-320 high precision intelligent acidity gauge (the water/soil ratio was 2.5:1). The conductivity was measured using a DDS-608 multifunctional conductivity meter (the water/soil ratio was 5:1). A potassium dichromate oxidation process in combination with a heating method was used to measure the soil organic carbon (SOC). Available nitrogen (AN) was determined using the alkaline hydrolysis–diffusion absorption method. Available phosphorus (AP) was determined using the molybdenum antimony anti-colorimetric method; available potassium (AK) was determined using the flame photometer method. Total nitrogen (TN) was determined using the Kjeldahl method; total phosphorus was determined using the sodium hydroxide melting–molybdenum antimony colorimetric method [35]. The permanganate titration method was used to determine catalase (CAT), sucrase (SUC), and urease (URE) was determined using 3,5-dinitro salicylic acid and sodium hypochlorite on the spectrophotometer using the colorimetry method [36].

2.4. Soil Bacterial Community Structure Analysis

The soil samples were stored at −80 °C and mailed to Beijing Novogene Biomedical Technology for high-throughput sequencing. Based on DNA extraction and quality control, PCR amplification and sequencing, and high-throughput sequencing and data analysis, the average raw reads reached 227,281. Following low-quality sequence removal, the mean effective reads were 217,099 (95.52% of raw reads). After denoising, the post-denoising effective reads averaged 207,311 (91.21% of raw reads). Subsequent chimera removal yielded high-quality sequences averaging 156,487 reads, accounting for 75.84% of the effective reads. The high-quality and sufficient-volume 16S rRNA gene (V3–V4 region) sequencing data from all samples support a robust comparative analysis of soil bacterial community composition in jujube forests across varying abandonment durations within the study area. The amplification primers of the bacterial PCR were ACTCCTACGGGAGGCAGCA and GGACTACHVGGTWTCTAAT.

2.5. Statistical Analysis and Data Analysis

Further analysis of the relationship between soil physicochemical factors and microbial communities was conducted using redundancy analysis (RDA) [37]. The bacterial diversity analysis was completed in Uparse software v7.0.1001, the typical correspondence analysis was completed in the software CANOCO 5, and the significant indigenous level was determined to be p < 0.05. Data analysis was performed using Excel 2010.

3. Results and Analysis

3.1. Characteristics of Soil Physical and Chemical Properties of Jujube Forests at Different Abandonment Years

We investigated the soil physical and chemical properties of the jujube forest land at different abandoned years (Figure 1). In general, the soil physical and chemical properties of woodland changed significantly with the increase in abandoned years. Among them, the contents of clay and silt increased first and then decreased with the increase in abandoned years. The highest soil bulk density was 1.23 g/cm3 after six years of abandonment, and the lowest was 1.03 g/cm3 after one year of abandonment. Soil moisture content was between 6% and 15%. Soil pH > 8 corresponds to alkaline status. Soil electrical conductivity decreased with the increase in abandoned years. Soil organic carbon content was between 6.98 and 9.22 g/kg. The contents of soil available phosphorus, soil available potassium, soil available nitrogen, and soil total nitrogen showed an increasing trend with the increase in abandonment years, with the lowest at one year and the highest at twenty years. Soil catalase activities were 1.07 mL/g·d, 0.88 mL/g·d, 0.95 mL/g·d, 1.02 mL/g·d at one year, three years, six years and twenty years after abandonment, respectively. With the increase in abandoned years, soil sucrase activity showed an upward trend: that is, the highest enzyme activity was 9.80 mg/g·d in 20 years. The change trend in soil urease activity was the same as that for soil sucrase activity.

3.2. Soil Bacterial Community Composition Characteristics of Jujube Forest at Different Abandoned Years

Studies have shown that Phylum Actinomycetota (34%), Proteobacteria (29%), Acidobacteriota (13%), Gemmatimonadetes (7%), Chloroflexota (7%) and Bacteroidetes (3%) are the most abundant soil bacterial groups in jujube forests. Among them, the relative abundance of actinomycete phyla was the highest at 20 years of abandonment (39.7%), followed by 6 years (38.4%), 3 years (31.3%) and 1 year (26.7%). The relative abundance distribution of Proteobacteria was 3 a (34.3%) > 1 a (30.7%) > 6 a (25.2%) > 20 a (24.1%); the relative abundance distribution of Acidobacteriota was 1 a (16.2%) > 3 a (12.6%) > 6 a (12%) > 20 a (11.3%).
Based on the taxonomic level of classes, the soil in the jujube forest was mainly dominated by Alphaproteobacteria (12%), Gammaproteobacteria (12%), Phylum Actinomycetota (11%), Thermoleophilia (11%) and Acidimicrobiia. As shown in Table 2, the thermophilic oil-producing bacteria were the most abundant in the abandoned jujube forest at 1 and 20 years, with relative abundances of 0.13 and 0.14, respectively. The Alphaproteobacteria were the most abundant in abandoned jujube forest at three and six years, with relative abundances of 0.16 and 0.14, respectively.
We further studied the relative abundance of the genus level of the soil bacterial community structure in jujube forest land at different abandoned years (Figure 2). It can be seen from the figure that Pseudonocardia and Geodermatophilus in bacterial communities have high abundance levels in the soil after one year of abandonment. The abundances of Mycobacterium, Ramllibacterhe and Sphingoaurantiacus in abandoned jujube forests years were high at three years. The abundance of Kricbtella was higher at six years of abandonment, and the relative abundance of Gemmatimonas was higher at twenty abandoned years, but this level was very low at one, three, and six abandoned years.

3.3. Diversity Analysis of Soil Bacterial Community

The species diversity analysis of samples from various plots is shown in Table 3. The Goods coverage index is close to 1, indicating that the sequencing depth is reasonable; the sequencing depth basically covered all species in the sample, the sequencing library reached saturation, and the results truly reflect the sample conditions. Chao 1 and the observed species index are used as the community richness index, while the Shannon and Simpson indexes are the community diversity index. Among them, the Shannon index of the bacterial community was between 11.54 and 12.06, the Chao 1 index was between 9296.42 and 11,888.5, and the observed species index was between 8828.5 and 10,838.7. The diversity index of the bacterial community from high to low was 1 a > 20 a > 6 a > 3 a. The diversity of the most abundant bacterial species in the soil of the jujube forest that had been abandoned for one year was higher, and the diversity of bacterial species in the soil of the jujube forest abandoned for three years was lower. With the increase in abandoned years, the richness of the soil bacteria first decreased and then increased.

3.4. Similarity Analysis of Soil Bacterial Community

It can be seen from Figure 3 that there were 10,561, 8680, 9031, and 9607 bacterial species in the soil samples of abandoned 1 a, 3 a, 6 a, and 20 a, respectively. There were 27,857 OTUs in the soil bacterial community of the jujube forest land under different abandoned years, of which 1258 OTUs were common bacterial species, accounting for 4.52%. With the increase in abandoned years, the number of soil bacterial species decreased first and then increased. The number of bacterial species was the largest after one year and the smallest at three years. The species composition of OTUs in 1-year-old and 3-year-old, 6-year-old, and 20-year-old jujube forests changed significantly, but there was little difference between 3-year-old and 6-year-old forests.

3.5. Relationship Between Soil Microbial Community and Soil Physicochemical Properties

The correlation between the soil microbial community and soil physicochemical indexes was analyzed (Table 4). It can be seen from the table that soil physicochemical properties affect soil microbial community composition. Among them, in the composition of the soil bacterial community, the relative abundance of Phylum Actinomycetota was significantly negatively correlated with soil clay, soil silt, and soil water content, while it was positively correlated with soil available nutrients. Proteobacteria was negatively correlated with soil nutrients and soil enzyme activities. Acidobacteriota has a strong correlation with soil mechanical composition. Gemmatimonadetes, Chloroflexota, and Verrucomicrobia were positively correlated with soil enzyme activities.
Further analysis of the relationship between soil physicochemical factors and microbial communities was conducted using redundancy analysis (RDA) (Figure 4). Among the soil bacterial community composition, the environmental factors with the highest contribution rate were soil water content, soil porosity and soil catalase activity, with a cumulative contribution rate of 97.9%. The interpretation rate of the first sorting axis is 86.75%, the interpretation rate of the second sorting axis is 13.09%, and the cumulative interpretation rate of the axis–axis-two is 99.84%. Among them, the bacterial community in abandoned year one and year twenty of the jujube forest was mainly related to the capillary water holding capacity and soil catalase, the bacterial community was mainly related to soil bulk density, soil total nitrogen, and soil organic carbon.

4. Discussions

At the phylum level, Phylum Actinomycetota, Proteobacteria, Acidobacteriota, Gemmatimonadetes, Chloroflexota and Bacteroidetes were the main phyla of soil bacteria in jujube plantations at different abandoned years; this finding is similar to the results of other studies on microbial diversity [38,39]. Actinomycetes, as saprophytic bacteria, produce a series of extracellular hydrolases that can degrade animal and plant polymers, including lignin, cellulose, chitin and other organic compounds [40]. They are important for the circulation of carbon, nitrogen, phosphorus, potassium and other elements in soil [41]. In this study, Phylum Actinomycetota had the highest relative abundance of soil bacterial phyla in the abandoned jujube forest. The main reason was that actinomycetes were usually the main soil microorganisms in the soil, and many microorganisms in these phyla could survive in various environments [42]. Secondly, Proteobacteria was the dominant bacterial group in the abandoned jujube forest. This may be because Proteobacteria are carbon-fixing microorganisms [16]. With the abandonment of forest land, the surface litter increased; the supply of vegetation litter and a large amount of dead root decomposition and other litter layers were important sources of soil organic carbon. As a kind of nutritious bacteria, Proteobacteria grew rapidly in the carbon-rich environment [43], so they were the dominant bacterial group.
At different abandoned years, the abundance of the soil bacterial community in the jujube forest was different, and the diversity was not significantly different (p < 0.05). With the increase in abandoned years, the abundance of the dominant genera of bacterial microorganisms also changed. Yang et al. showed that soil mechanical composition and soil nutrients played an important role in the growth of soil microorganisms [44]. There were differences in soil nutrients in abandoned forest land, which led to differences in soil microbial communities. At the same time, the organic carbon in abandoned jujube forest land increased through biological pathways such as plant residues, which led to increased microbial carbon sources and an increase in the relative abundance of most genera in bacteria. Therefore, abandonment may lead to the enhancement of the carbon and nitrogen cycling function of microorganisms. The more soil microbial OTUs there are, the more species of soil bacteria. In this study, with the increase in abandoned years, the number of soil bacteria OTUs showed an increasing trend. Sun et al. found that vegetation diversity was positively correlated with microbial diversity [18]. With the increase in herbaceous vegetation in abandoned forests, vegetation can increase microbial diversity. The aboveground litter increased with the increase in the duration of abandonment. The litter was the nutrient source of the soil microorganisms [45], so the number of soil bacterial OTUs showed an increasing trend.
Different microbial communities have different responses to soil factors. In this study, soil water content is the main factor affecting the soil microbial community in the abandoned jujube forest, which is consistent with the results of Liu et al. [26] and Zhang et al. [46]. The main reason for this is that soil water content affects soil aeration, resulting in changes in the number of nutritional bacteria and aerobic bacteria, as well as changes in microbial abundance and biological activity, which further affects the composition and diversity of microbial communities [47,48]. At the same time, soil water content is necessary for the growth and reproduction of soil bacteria and is also one of the most important factors affecting the composition of soil bacterial communities.

5. Conclusions

There are significant differences in the soil physical and chemical properties of jujube plantations with different abandonment years in the Loess area of northern Shaanxi. With the increase in abandonment years, the soil properties are optimized. Phylum Actinomycetota, Proteobacteria and Acidobacteriota were the main bacterial groups in the four types of abandoned jujube forest at the phylum level, and Alphaproteobacteria, Gammaproteobacteria, Phylum Actinomycetota, Thermoleophilia and Acidimicrobiia were the dominant groups at the class level. With the increase in abandoned years, the soil bacterial richness showed a trend of first decreasing and then increasing. Soil water content plays an important role in driving the change in the soil microbial community in jujube forest land with different abandoned years. Therefore, for future ecological restoration and soil quality enhancement of abandon jujube forest, the optimal utilization of soil bacterial communities should be achieved through a comprehensive consideration of soil moisture conditions, with corresponding improvement strategies tailored accordingly.

Author Contributions

Conceptualization, N.A. and M.Z.; methodology, N.A. and J.G.; software, N.A. and X.Y.; validation, N.A., M.Z. and J.G.; formal analysis, N.A.; investigation, N.A. and J.G.; data curation, N.A.; writing—original draft preparation, N.A.; writing—review and editing, N.A. and J.G.; visualization, N.A., X.Y. and J.G.; supervision, M.Z., J.G. and X.Y.; project administration, N.A. All authors have read and agreed to the published version of the manuscript.

Funding

This research work was supported by the National Key Research and Development Plan of China (2023YFF1305104) and; the Research Project of Yan’an University (2023JBZR-20).

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding authors.

Acknowledgments

The authors greatly appreciate the assistance of Qiaoyu Zong and Dahong Qiang.

Conflicts of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this study.

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Diversity 17 00462 g001
Figure 1. Soil physical and chemical properties. Note: A1 instead of abandoned 3 a; C1 instead of abandoned 6 a; D1 instead of abandoned 1 a; E1 instead of abandoned 20 a.
Figure 1. Soil physical and chemical properties. Note: A1 instead of abandoned 3 a; C1 instead of abandoned 6 a; D1 instead of abandoned 1 a; E1 instead of abandoned 20 a.
Diversity 17 00462 g001
Diversity 17 00462 g002
Figure 2. Genus-level species composition heat map of species clusters. Note: A1 instead of abandoned 3 a; C1 instead of abandoned 6 a; D1 instead of abandoned 1 a; E1 instead of abandoned 20 a.
Figure 2. Genus-level species composition heat map of species clusters. Note: A1 instead of abandoned 3 a; C1 instead of abandoned 6 a; D1 instead of abandoned 1 a; E1 instead of abandoned 20 a.
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Diversity 17 00462 g003
Figure 3. Venn diagram of the ASV/OTU number based on bacteria in soils. Note: A1 instead of abandoned 3 a; C1 instead of abandoned 6 a; D1 instead of abandoned 1 a; E1 instead of abandoned 20 a.
Figure 3. Venn diagram of the ASV/OTU number based on bacteria in soils. Note: A1 instead of abandoned 3 a; C1 instead of abandoned 6 a; D1 instead of abandoned 1 a; E1 instead of abandoned 20 a.
Diversity 17 00462 g003
Diversity 17 00462 g004
Figure 4. Redundancy analysis (RDA) of bacterial community structure and soil physicochemical properties.
Figure 4. Redundancy analysis (RDA) of bacterial community structure and soil physicochemical properties.
Diversity 17 00462 g004
Table 1. Basic conditions of sampling points.
Table 1. Basic conditions of sampling points.
Sample PlotsElevation/mSlopes PositionAbandoned Years (a)Land Preparation Method
Jujube forest880Downslope segment1None
Jujube forest867Downslope segment3None
Jujube forest836Downslope segment6None
Jujube forest880Downslope segment20None
Note: “Abandoned years” means the number of years that have elapsed between the cessation of the last cultivation/management activity on the previously cultivated jujube land and the year of sampling in this study.
Table 2. Composition of the soil bacterial community at the class level.
Table 2. Composition of the soil bacterial community at the class level.
Group DistributionRelative Abundance of Bacteria
1 a3 a6 a20 a
Alphaproteobacteria0.100.160.140.10
Gammaproteobacteria0.100.150.130.09
Phylum Actinomycetota0.120.120.100.12
Thermoleophilia0.130.080.090.14
Acidimicrobiia0.070.080.050.07
Subgroup 60.050.060.080.05
Gemmatimonadetes0.060.050.070.06
Deltaproteobacteria0.050.030.040.05
Blastocatellia0.040.030.040.03
Bacteroidia0.020.030.030.03
Miscellaneous0.260.210.230.26
Total1.001.001.001.00
Table 3. Alpha diversity index of the sample.
Table 3. Alpha diversity index of the sample.
Sample AreaShannon IndexSimpson IndexChao 1 IndexObserved Species IndexGoods Coverage Index
1 a12.060.999311,888.5010,838.70.9815
3 a11.540.99909296.428828.50.9884
6 a11.690.99909777.039199.20.9874
20 a11.960.99929867.509711.70.9925
Table 4. Correlation analysis of bacterial community (phyla classification level) and soil physical and chemical properties.
Table 4. Correlation analysis of bacterial community (phyla classification level) and soil physical and chemical properties.
Gate Level ClassificationActinob
Acteria		Proteoba
Cteria		Acidobac
Teria		Gemmatimo
Nadetes		Chloro
Flexi		Bacte
Roidetes		Plancto
Mycetes		Verruco
Microbia		Rokub
Acteria		Patesci
Bacteria
Clay−0.984 *0.7130.946−0.0650.3880.7840.738−0.6010.5530.087
Silt−0.971 *0.7460.926−0.1080.210.5330.768−0.770.7520.196
Sand0.981 *−0.746−0.9370.101−0.242−0.58−0.770.748−0.725−0.179
SM−0.958 *0.9080.789−0.398−0.0490.450.922−0.8980.8690.471
BD−0.8490.4240.9410.2510.6940.910.455−0.2680.219−0.263
SMC0.061−0.164−0.040.1270.480.66−0.160.558−0.639−0.325
CC0.944−0.843−0.8230.2950.006−0.394−0.8590.89−0.875−0.394
TV0.662−0.106−0.899−0.578−0.868−0.794−0.1420.039−0.0170.564
EC−0.0210.36−0.169−0.513−0.795−0.7190.343−0.6670.7260.67
pH−0.5250.6040.404−0.341−0.417−0.2680.606−0.880.9230.52
SOC−0.524−0.070.8320.7280.8750.612−0.0330.039−0.034−0.679
AP0.091−0.252−0.020.2420.5640.66−0.2460.625−0.7−0.434
TN−0.234−0.1130.3730.3950.7940.875−0.0930.448−0.52−0.544
ALN0.087−0.093−0.13−0.0230.3350.596−0.0950.499−0.585−0.182
AK0.382−0.64−0.1620.570.6680.418−0.6310.888−0.925−0.727
CAT0.732−0.941−0.3950.7540.276−0.494−0.9380.716−0.642−0.708
SUC0.392−0.478−0.3020.2770.4450.4−0.4780.8−0.857−0.468
URE0.076−0.23−0.0140.2210.5540.668−0.2230.608−0.684−0.414
Note: * Significant indigenous correlation at the 0.05 level (bilateral).
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Ai, N.; Zou, M.; Yu, X.; Gao, J. Diversity of the Soil Bacterial Community of Abandoned Jujube Land in the Loess Area of Northern Shaanxi in Different Years. Diversity 2025, 17, 462. https://doi.org/10.3390/d17070462

AMA Style

Ai N, Zou M, Yu X, Gao J. Diversity of the Soil Bacterial Community of Abandoned Jujube Land in the Loess Area of Northern Shaanxi in Different Years. Diversity. 2025; 17(7):462. https://doi.org/10.3390/d17070462

Chicago/Turabian Style

Ai, Ning, Menghuan Zou, Xuejiao Yu, and Jie Gao. 2025. "Diversity of the Soil Bacterial Community of Abandoned Jujube Land in the Loess Area of Northern Shaanxi in Different Years" Diversity 17, no. 7: 462. https://doi.org/10.3390/d17070462

APA Style

Ai, N., Zou, M., Yu, X., & Gao, J. (2025). Diversity of the Soil Bacterial Community of Abandoned Jujube Land in the Loess Area of Northern Shaanxi in Different Years. Diversity, 17(7), 462. https://doi.org/10.3390/d17070462

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