Effects of Organic Fertilizer Supply on Soil Properties, Tomato Yield, and Fruit Quality: A Global Meta-Analysis

: The increased use of chemical fertilizer input in agricultural production and the promotion of sustainable agriculture encourage researchers around the globe to undertake experiments regarding application of organic fertilizers on tomato production. This study aims to amalgamate the comprehensive effects of organic fertilizer application compared with the pure application of chemical fertilizers (100% CF) on soil properties, tomato yield, and fruit quality through meta-analysis. It helps to provide a certain reference for the sustainable development of circular agriculture systems in tomato planting. Articles related to the impact of organic


Introduction
Tomato is the second largest vegetable crop in the human diet worldwide, after potato, with a very high nutritional and economic value [1,2].In 2000, the total tomato production exceeded 100 million tons around the globe, and in 2021, the world's total tomato output was 182.05 million tons.The tomato planting area around the world also increased from 3.16 million hectares in 1994 to 5.055 million hectares in 2020 [3].Tomatoes are an essential food for people and a valuable source of nourishment.Tomatoes are a source of highquality vitamin C required by the human body [4].Tomato and other vegetable crops have a large requirement for nitrogen.Driven by global demand and economic interests, farmers generally use excessive chemical fertilizers in order to pursue high yields [5].The extensive application of chemical fertilizers can lead to a decrease in soil pH, which in turn leads to a decrease in the abundance of bacterial communities [6].Moreover, intensive agriculture has also reduced soil biodiversity, increased the risk of soil-borne disease outbreaks, and seriously threatened the sustainable development of agriculture [7].Similarly, over-manuring can also lead to many potential adverse factors, such as nitrate accumulation or leaching [8,9].In addition, soil degradation such as acidification and salinization are common in vegetable fields [10].The application of organic fertilizers has significantly improved the activity of microbial enzymes such as urease, catalase, and β-glucosidase, which are the biological indicators of the soil [11].The main problems in the current vegetable system are reduced productivity, environmental degradation, and soil quality degradation [12,13].Therefore, the application of organic fertilizers is an efficient and long-lasting solution.Previous studies have shown that the application of organic fertilizer is a sustainable vegetable planting strategy [14], it increases the yield of vegetables [15], reduces the loss of nutrients in the soil [16], reduces the greenhouse gas emission in agricultural production [17], controls the occurrence of vegetable diseases [18], and keeps the soil healthy enough for a long time [19].The long-term application of organic fertilizers can improve the availability of soil phosphorus, which is affected by the comprehensive impact of organic fertilizer input, soil properties, and climatic conditions [20].Bio-organic fertilizers usually combine the effects of microbial fertilizers and organic fertilizers with specialized functional microorganisms, manifold with harmless and decomposed organic materials and animal and plant residues as the source [21].Compared with natural fermentation, bio-organic fertilizers are added with microbial agents to increase the beneficial bacteria in the fertilizer.In intensive vegetable cultivation, the use of microbial agents and compost to form bio-organic fertilizer is a win-win approach, which can increase yield and reduce nitrogen loss [22].
The Meta-analysis method is a statistical method which can comprehensively analyze the statistical results of several independent studies [23,24].It was used to study the effects of different nitrogen fertilizer application rates on tomato yield, quality, and soils' physical and chemical properties [3].Others used meta-analysis to investigate the effect of different microbial groups' biological control agents on tomato bacterial wilt [25,26].The feasibility of using meta-analysis in tomato research is comprehensively explained.This study utilizes meta-analysis to explain the changes in properties of the soil and the yield and quality of the tomato after the application of different organic fertilizers (bio-organic fertilizers and ordinary organic fertilizers) compared with the pure application of chemical fertilizers (100% CF) and the correlation between yield, quality, and soil.The results of this study can provide a theoretical basis for the selection of organic fertilizers for different purposes in tomato planting and sustainable green agriculture.

Data Collection
Articles related to the impact of organic fertilizers on tomato planting were searched on the Web of Science website (www.webofscience.com,accessed on 30 June 2022), Science direct (www.sciencedirect.com,accessed on 30 June 2022), and Google Scholar (scholar.google.com,accessed on 30 June 2022).All the articles published from 2000 to 30 June 2022, were systematically reviewed.The relevant experiments on tomato yield, quality, and soil with organic fertilizers were included in the analysis.According to the requirements for data integration in meta-analysis and the purpose of this study, screening was carried out for: (1) The same study must include the treatment of organic fertilizer application and the control treatment of 100% CF.Organic fertilizer application was used in data processing.Fertilizer was used as the treatment group and chemical fertilizer only (100% CF) was used as the control group; (2) The article must have the mean of the relevant data, the standard deviation SD (can be converted by the standard error SE, SE = SD/ √ n), and the number of repetitions n.The data in the table can be directly extracted.The data in the figure were extracted by using the function of the image digitization tool in the tools in origin 2022.For data without standard deviation or standard error, we use 10% of its mean value (SD = mean × 10%) [27]; (3) Articles or data related to activated carbon was excluded from meta-analysis, since the literature revealed that activated carbon is a soil conditioner rather than an organic fertilizer and the fertility of activated carbon is difficult to release into the soil [28,29]; (4) Organic fertilizers are divided into two subgroups.The first type of bio-organic fertilizers are organic fertilizers with added microorganisms (Bacillus, Trichoderma, etc.), vermicompost (The studied literature has shown that vermicompost is a subdivided peat-like substance that biodegrades and stabilizes organic matter through the interaction between earthworms and microorganisms.It is produced through a non-thermophilic process [30], with more total microorganism and higher biological activity [31,32]).The second type of common organic fertilizer are commercial organic fertilizer, green manure, various manure, various straw compost, biogas residue, manure, etc.; (5) The basic information of test site, organic fertilizer type, and so on is relatively complete and reliable.
This research includes relevant test data from all around the world, including data from five continents, as shown in Figure 1, including 53 test points in Asia, 37 test points in Europe, 21 test points in North America, 4 test points in South America, and 9 test sites in Africa.The record included journal name, article title, test date, test location, test point coordinates (Table S1), and other information which were extracted from 124 documents.Screening revealed that yield was included in 373 groups; fruit data: nitrate in 48 groups, sugar in 85 groups, lycopene in 130 groups, protein in 30 groups; and soil data: electrical conductivity (Ec)in 115 groups, pH (<6, acid soil) in 119 groups, pH (6~8, neutral soil) in 101 groups, soil organic matter (SOM) in 173 groups, soil total nitrogen (TN) in 133 groups, total phosphorus (TP) in 57 groups, total potassium (TK) in 41 groups, ammonium nitrogen (NH 4 + -N) in 66 groups, nitrate nitrogen (NO 3 − -N) in 80 groups, available phosphorus (AvP) in 168 groups, available potassium (AvK) in 145 groups, soil bacteria in 63 groups, soil fungi in 63 groups, soil urease in 30 groups, and soil catalase in 31 groups (Table S1).A total of 2041 groups of data.

Meta-Analysis
Metawin 2.1 software was used for meta-analysis, the response ratio was selected as the effect ratio for different indicators.The formula for calculating the response ratio is [33]:

Meta-Analysis
Metawin 2.1 software was used for meta-analysis, the response ratio was selected as the effect ratio for different indicators.The formula for calculating the response ratio is [33]: where X t represents the average value of the treatment group (applied organic fertilizer), X c represents the average value of the control group (100% CF).The variation coefficient V(R), weight (W ij ), weighted effect ratio (R ++ ), standard error S(R ++ ), and 95% CI were calculated as follow [3]: The results of the studies were tested for heterogeneity prior to analysis.Fixed effect model (FEM) was used when probability value was p > 0.1, it is the indicator of heterogeneity of the data set.Random effect model (REM) was used when p ≤ 0.1, indicated the data set is not heterogeneous [34].The smaller the standard deviation of the effect size, the greater the weight assigned, the weighted effect ratio (RR ++ ) is the percentage of treatment relative to the control increase and decrease.If the 95% confidence interval (95%CI = (e RR++ − 1) × 100%) of a set of data does not coincide with 0, it is considered that the treatment has a significant impact on the target variable, and the interval < 0 has a negative effect, and > 0 has a positive effect [35].

Mapping Software and Correlation Analysis
Meta-analysis was conducted by Metawin 2.1 software, forest plot and regression analysis were carried by GraphPad Prism 8.0.2,Origin 2022 was utilized for normal distribution fitting and correlation analysis, tables were designed by excel 2007, and the world map was drawn by ArcMap 10.7 in ArcGIS.

Heterogeneity Test and Analysis of Organic Fertilizer Application on Tomato Yield and Quality and Soil Properties
The Q test (the Q value represents the standardized sum of squares of the effect value, the larger the Q value, the greater the heterogeneity) and the I 2 test (the I 2 value represents the heterogeneity of individual effect values to the total effect value, the larger the I 2 value, the greater the heterogeneity) were carried out for meta-analysis.The heterogeneity analysis of tomato yield and quality and soil physical and chemical properties after the application of organic fertilizers was shown in Table 1.The results showed that, except for Soil urease (p < 0.1), all our indexes met p < 0.01.The cut-off values for high, medium, and low heterogeneity were 75%, 50%, and 25%, respectively [36] Since there is a difference between field and potted production data, in order to reduce this difference, the effect ratio InR ++ is used as the observed value, and origin 2023 is used for frequency statistics, and the number of frequencies is used as the vertical axis to make a histogram.Curve fitting is performed using the GaussAmp function, and the processing of the following data is similar.According to the classification of soil pH, pH < 6 is classified as acidic soil, pH 6~8 is classified as neutral soil, and pH > 8 is classified as alkaline soil and the research objects were all classified by pH under 100% CF.Since the data sets of alkaline soils are few and did not pass the heterogeneity test during data extraction, thus alkaline soils are not specifically studied.The normal distribution was fitted to the observed values of meta-analysis (Figure 2).Since there is a difference between field and potted production data, in order to reduce this difference, the effect ratio InR++ is used as the observed value, and origin 2023 is used for frequency statistics, and the number of frequencies is used as the vertical axis to make a histogram.Curve fitting is performed using the GaussAmp function, and the processing of the following data is similar.According to the classification of soil pH, pH<6 is classified as acidic soil, pH 6~8 is classified as neutral soil, and pH>8 is classified as alkaline soil and the research objects were all classified by pH under 100% CF.Since the data sets of alkaline soils are few and did not pass the heterogeneity test during data extraction, thus alkaline soils are not specifically studied.The normal distribution was fitted to the observed values of meta-analysis (Figure 2).
When organic fertilizers (the total) were applied, compared with the 100% CF (Figure 3), Soil Ec was not significantly reduced (its 95% CI passed through the zero line), however bio-organic fertilizer (BF) could significantly reduce Ec by 13.66% (95% CI, −25.22% −2.09%), similarly, ordinary organic fertilizer (OF) could not significantly improve Soil Ec.When the pH < 6, the application of organic fertilizers can increase the soil pH, the total can significantly increase the soil pH by 7.98% (95% CI, +5.82% +10.13%),BF can increase the pH by 6.32% (95% CI, +1.86% +10.77%) whereas OF could significantly increase the pH by 8.52% (95% CI, +6.03% +11.01%), although the difference between groups was not significant (p = 0.38, Table 1).When the pH was 6-8, the application of organic fertilizers could still increase the pH, but the increase was smaller compared with pH<6.The increase in the pH due to the total was 3.35% (95% CI, +2.36% +4.33%), BF can significantly increase the pH by 3.42% (95% CI, +1.56% +5.28%), whereas OF can significantly increase the pH by 3.31% (95% CI, +2.12% +4.50%), the difference between groups was not significant (p = 0.92).The results of the meta-analysis showed that bio-organic fertilizer could significantly reduce Soil Ec compared with the 100% CF.In acidic soils, organic fertilizers could increase Soil pH.In neutral soils, organic fertilizers could still increase pH, but the increase was small.When organic fertilizers (the total) were applied, compared with the 100% CF (Figure 3), Soil Ec was not significantly reduced (its 95% CI passed through the zero line), however bioorganic fertilizer (BF) could significantly reduce Ec by 13.66% (95% CI, −25.22% −2.09%), similarly, ordinary organic fertilizer (OF) could not significantly improve Soil Ec.When the pH < 6, the application of organic fertilizers can increase the soil pH, the total can significantly increase the soil pH by 7.98% (95% CI, +5.82% +10.13%),BF can increase the pH by 6.32% (95% CI, +1.86% +10.77%) whereas OF could significantly increase the pH by 8.52% (95% CI, +6.03% +11.01%), although the difference between groups was not significant (p = 0.38, Table 1).When the pH was 6-8, the application of organic fertilizers could still increase the pH, but the increase was smaller compared with pH < 6.The increase in the pH due to the total was 3.35% (95% CI, +2.36% +4.33%), BF can significantly increase the pH by 3.42% (95% CI, +1.56% +5.28%), whereas OF can significantly increase the pH by 3.31% (95% CI, +2.12% +4.50%), the difference between groups was not significant (p = 0.92).The results of the meta-analysis showed that bio-organic fertilizer could significantly reduce Soil Ec compared with the 100% CF.In acidic soils, organic fertilizers could increase Soil pH.In neutral soils, organic fertilizers could still increase pH, but the increase was small.

Meta-Analysis of Organic Fertilizer Application on Soil Nutrient Index
The application of organic fertilizer significantly manipulates the nutrient index of the soil, and this change can be traced.Frequency statistics were performed on the response ratio (InR) of the soil's SOM, TN, TP, TK, NH4 + -N, NO3 − -N, AvP, and AvK, and fitted in the normal distribution.The fitting results are shown in Figure 4, whose R 2 values are 0.8966, 0.8492, 0.9577, 0.9678, 0.9185, 0.9415, 0.9481, 0.9067, and their P values are all <0.001.The fitting results were significant and have certain research significance.

Meta-Analysis of Organic Fertilizer Application on Soil Microbial Quantity and Enzyme Activity
The application of organic fertilizer has a certain impact on the microbial and enzyme activities in the soil, and the frequency of its response ratio (InR) has been fitted with a normal distribution.The results are shown in Figure 6.Soil bacteria, fungi, urease, catalase whose R 2 = 0.9147, 0.9943, 0.8805, 0.9523, respectively, have p values < 0.0001.The fitting results are satisfactory, which has certain research significance.The total compared with the 100% CF significantly increased Soil bacteria by 5.94% (95% CI, +5.73% +6.15%), and BF and OF were significantly increased by 4.86% (95%CI, +4.49% +5.23%) and 6.54% (95% CI, +6.27% +6.80%), respectively.The difference between the groups was significant (Table 1).However, Soil fungi passed the zero line, and the total and OF could not be significantly reduced, and BF could not be significantly increased.Soil urease is related to the nitrogen cycle in soil, and soil catalase activity is related to soil detoxification ability.Applying organic fertilizer (the total) can significantly increase soil urease by 22.32% (95%CI, +11.28% +33.35%),BF cannot be significantly increased after the zero line, and OF can be significantly increased by 25.41% (95%CI, +11.35% +39.47%) (Figure 7).Through the application of organic fertilizers, the total, BF, and OF could significantly increase soil catalase activity by 17.68% (95% CI, +13.17% 22.18%), 24.55% (95% CI, +16.92% 32.18%), and 12.31% (95% CI, +6.14% 18.47%), respectively.The results of the meta-analysis showed that the application of organic fertilizers can increase soil bacteria, and also that BF has a better effect than OF, whereas no significant effect was revealed on soil fungi.The application of organic fertilizer can increase the activity of soil urease, whereas BF showed no significant effect.The effect of BF is better than that of OF as it can increase the activity of soil catalase.Soil urease is related to the nitrogen cycle in soil, and soil catalase activity is related to soil detoxification ability.Applying organic fertilizer (the total) can significantly increase soil urease by 22.32% (95%CI, +11.28% +33.35%),BF cannot be significantly increased after the zero line, and OF can be significantly increased by 25.41% (95%CI, +11.35% +39.47%) (Figure 7).Through the application of organic fertilizers, the total, BF, and OF could significantly increase soil catalase activity by 17.68% (95% CI, +13.17% 22.18%), 24.55% (95% CI, +16.92% 32.18%), and 12.31% (95% CI, +6.14% 18.47%), respectively.The results of the meta-analysis showed that the application of organic fertilizers can increase soil bacteria, and also that BF has a better effect than OF, whereas no significant effect was revealed on soil fungi.The application of organic fertilizer can increase the activity of soil urease, whereas BF showed no significant effect.The effect of BF is better than that of OF as it can increase the activity of soil catalase.

Meta-Analysis of Organic Fertilizer Application on Tomato Yield and Quality
The fitting results of the yield data are shown in Figure 8A, the data collected for the study satisfies the normal distribution, which has a good research value.The application of organic fertilizers (the total) increased the yield by 3.48% (95% CI, +0.28% +6.67%) compared with 100% CF.The yield of bio-organic fertilizer (BF) was increased by 14.15% (95% CI, +8.28% +20.02%).Since the confidence interval of Ordinary organic fertilizer (OF) (95%

Meta-Analysis of Organic Fertilizer Application on Tomato Yield and Quality
The fitting results of the yield data are shown in Figure 8A, the data collected for the study satisfies the normal distribution, which has a good research value.The application of organic fertilizers (the total) increased the yield by 3.48% (95% CI, +0.28% +6.67%) compared with 100% CF.The yield of bio-organic fertilizer (BF) was increased by 14.15% (95% CI, +8.28% +20.02%).Since the confidence interval of Ordinary organic fertilizer (OF) (95% CI, −4.91% +2.72%) passed through zero, the effect of organic fertilizer on the yield was not significant, and the difference between groups was p < 0.001 (Table 1).The results of the meta-analysis showed that compared with the total, BF significantly increased the yield, while OF had no significant effect.CI, −4.91% +2.72%) passed through zero, the effect of organic fertilizer on the yield was not significant, and the difference between groups was p < 0.001 (Table 1).The results of the meta-analysis showed that compared with the total, BF significantly increased the yield, while OF had no significant effect.The fitting of the normal distribution was carried out during the data processing.The data for the meta-analysis revealed the normal distribution, which is of research significance (Figure 9).The application of organic fertilizers can significantly reduce the nitrate content of tomato fruit by 12.66% (95% CI, −21.81% −3.50%) compared with the 100% CF.BF cannot significantly reduce tomato nitrate, whereas OF can significantly reduce tomato nitrate by 13.02% (95% CI, −25.20% −0.84%) (Figure 10).The application of organic fertilizers (the total) can significantly increase the tomato sugar content by 4.79% (95% CI, +2.41% +7.17%) compared with 100% CF.BF cannot significantly reduce the tomato sugar content after passing through the zero line, and OF can significantly increase the tomato sugar content by 10.66% (95% CI, +7.50% +13.82%).The application of the total can significantly increase the lycopene content of tomato fruit by 4.80% (95% CI, +2.01%+7.58%), and BF cannot significantly reduce the fruit lycopene content after passing through the zero line.Ordinary organic fertilizer could significantly increase the lycopene content by The fitting of the normal distribution was carried out during the data processing.The data for the meta-analysis revealed the normal distribution, which is of research significance (Figure 9).The application of organic fertilizers can significantly reduce the nitrate content of tomato fruit by 12.66% (95% CI, −21.81% −3.50%) compared with the 100% CF.BF cannot significantly reduce tomato nitrate, whereas OF can significantly reduce tomato nitrate by 13.02% (95% CI, −25.20% −0.84%) (Figure 10).The application of organic fertilizers (the total) can significantly increase the tomato sugar content by 4.79% (95% CI, +2.41% +7.17%) compared with 100% CF.BF cannot significantly reduce the tomato sugar content after passing through the zero line, and OF can significantly increase the tomato sugar content by 10.66% (95% CI, +7.50% +13.82%).The application of the total can significantly increase the lycopene content of tomato fruit by 4.80% (95% CI, +2.01%+7.58%), and BF cannot significantly reduce the fruit lycopene content after passing through the zero line.Ordinary organic fertilizer could significantly increase the lycopene content by 10.78% (95% CI, +7.04% +14.52%).The protein content of tomato significantly increased by 13.82% (95% CI, +7.56% +20.08%) after the application of organic fertilizer (the total), whereas BF significantly increased the protein content by 10.12% (95% CI, +1.30% +18.93%) and OF significantly increased the protein of tomato fruit by 18.30% (95% CI, +8.47% +28.13%).There was no significant difference between the groups (p = 0.18, Table 1).The meta-analysis revealed that OF can significantly improve tomato fruit quality compared with BF.

Regression Analysis of Yield after Organic Fertilizer Application
The yield index is particularly important in actual production, so we specially analyzed it in the regression analysis.Due to the differences between potted plants and fields, and the differences between measurement methods, to eliminate this difference, response ratio (InR) was used as the observed value when performing regression analysis, the regression analysis was performed after one-to-one correspondence.This correlation represents the increase or decrease in output which is related to the increase or decrease of a certain indicator (i.e., InR = 0.1, indicated the increase is 10.52%).When this range is correlated, the same indicator itself is also relevant.In terms of quality indicators, yield is positively correlated with lycopene.Among the soil indicators, yield is significantly positively correlated with soil Ec.When the pH of the 100% CF is less than 6, there is a significant positive correlation between yield and pH.Similarly, there is a significant positive correlation between yield and pH when pH = 6~8, and the slopes of the two are similar (the slope of Figure 11C is

Regression Analysis of Yield after Organic Fertilizer Application
The yield index is particularly important in actual production, so we specially analyzed it in the regression analysis.Due to the differences between potted plants and fields, and the differences between measurement methods, to eliminate this difference, response ratio (InR) was used as the observed value when performing regression analysis, the regression analysis was performed after one-to-one correspondence.This correlation represents the increase or decrease in output which is related to the increase or decrease of a certain indicator (i.e., InR = 0.1, indicated the increase is 10.52%).When this range is correlated, the same indicator itself is also relevant.In terms of quality indicators, yield is positively correlated with lycopene.Among the soil indicators, yield is significantly positively correlated with soil Ec.When the pH of the 100% CF is less than 6, there is a significant positive correlation between yield and pH.Similarly, there is a significant positive correlation between yield and pH when pH = 6~8, and the slopes of the two are similar (the slope of Figure 11C

Correlation Analysis of Soil Properties and Tomato Yield, Fruit Quality after Application of Organic Fertilizer
Similarly, we used the response ratio (InR) of all indicators as the observed value and used the Correlation Plot in origin 2022′s Apps to conduct a correlation analysis.The Correlation Type was selected as Pearson, and the significance level was selected as 0.05.As shown in Figure 12, the correlation of output is consistent with the regression analysis results in Figure 11.Fruit nitrate was significantly positively correlated with lycopene, soil pH (<6), pH (6~8), and TK, and significantly negatively correlated with fruit sugar and soil TN.Fruit sugar was significantly positively correlated with fruit protein, soil Ec, TN, NO3 − -N, and bacteria, and significantly negatively correlated with soil NH4 + -N.Lycopene was significantly positively correlated with soil SOM, TN, NO3 − -N, and AvK, and was significantly negatively correlated with soil NH4 + -N.Protein was significantly positively correlated with soil SOM, and negatively correlated with Soil pH (6-8) and Soil nitrate nitrogen.Soil Ec was significantly positively correlated with Soil pH (<6), TN, TP, TK, NO3 − -N, AvP, AvK, and urease, and significantly negatively correlated with Soil pH (6~8).pH (<6) was significantly positively correlated with Soil TN, TP, TK, and NH4 + -N, and significantly negatively correlated with soil fungi and catalase.Soil pH (6~8) was significantly negatively correlated with soil SOM and AvP.Soil SOM was significantly positively correlated with Soil TN, AvP, AvK, and bacteria, and significantly negatively correlated with soil catalase.Soil TN was significantly negatively correlated with soil TP, TK, AvP, AvK, Bacteria, and Soil catalase.Soil TP was significantly positively correlated with Soil TK, AvP, and AvK.Soil TK was significantly positively correlated with Soil NO3 − -N and The results of the regression analysis showed that when the pH was slightly acidic, the increase in yield was the highest.The results revealed that the application of organic fertilizers has a significant positive correlation with SOM.The slope of SOM is 0.278.Similarly, the application of organic fertilizers cannot significantly increase or decrease soil ammoniacal nitrogen and nitrate nitrogen, and the slope of NH 4 + -N (0.231) is greater than the slope of NO 3 − -N (0.178), indicating that the yield increases with the increase of NH 4 + -N is greater than NO 3 − -N.Among the nutrient indicators, yield has no significant correlation with total nutrients, but it is significantly positively correlated with AvP, and its slope is the highest (0.772).In addition, yield is also significantly positively correlated with soil urease (slope is 1.26).The regression analysis results showed that yield has a strong correlation with lycopene in the quality index, also when the soil electrical conductivity and AvP increases, the yield increases.Tomato yields are higher when the soil is slightly acidic.Its yield has a strong correlation with soil nitrogen-related indicators (NH 4 + -N, NO 3 − -N, urease).

Correlation Analysis of Soil Properties and Tomato Yield, Fruit Quality after Application of Organic Fertilizer
Similarly, we used the response ratio (InR) of all indicators as the observed value and used the Correlation Plot in origin 2022's Apps to conduct a correlation analysis.The Correlation Type was selected as Pearson, and the significance level was selected as 0.05.
As shown in Figure 12, the correlation of output is consistent with the regression analysis results in Figure 11.Fruit nitrate was significantly positively correlated with lycopene, soil pH (<6), pH (6~8), and TK, and significantly negatively correlated with fruit sugar and soil TN.

Effects of Organic Fertilizer Application on Soil Properties
In our study, a meta-analysis study showed that only bio-organic fertilizers (BF nificantly reduced soil Ec by 13.66%, while ordinary organic fertilizers (OF) did not

Effects of Organic Fertilizer Application on Soil Properties
In our study, a meta-analysis study showed that only bio-organic fertilizers (BF) significantly reduced soil Ec by 13.66%, while ordinary organic fertilizers (OF) did not (Figure 3).Both kinds of organic fertilizers could significantly increase soil pH (acid soil, <6 and neutral soil, 6~8).In fact, the application of organic fertilizers can provide long-term fertility for agricultural production [37].It is speculated that long term fertility is closely related to the improvement of soil conductivity through the input of organic fertilizer to avoid or reduce the risk brought by inorganic fertilizer [38].Vermicomposting (BF) has the lowest electrical conductivity compared with other organic fertilizers [39].Some studies have suggested that the excessive application of a certain compost (OF) in tomato planting will lead to the excessive concentration of certain ions, which ultimately leads to the death of tomatoes [40], hence indicating that some organic fertilizers do not reduce Ec but rather increase Ec.Organic fertilizers can activate soil nutrients, and thus improve soil fertility [41,42].The biodegradation and transformation of organic matter in organic fertilizers can significantly increase the metabolic activity of microorganisms, activate soil nutrients, and promote the absorption of nutrients by crops [43].It is evident from the meta-analysis that the application of organic fertilizers can significantly increase soil SOM, TN, TP, TK, AvP, and AvK compared with 100% CF, but it has no significant effect on NH 4 + -N and NO 3 − N (Figure 5).The effect of BF was not as good as OF on total nutrients.However, the effects of AvP and AvK were equivalent.Studies have proposed that BF can improve AvP better than OF [44].Compared with conventional fertilization, the contents of AvN, AvP, and AvK in soil treated with organic fertilizer and microbial preparation were increased by 27.7%, 12.3%, and 133.7% [45], respectively, which fully indicated the characteristics of 100% CF leaching easily.Studies have shown that the combined application of organic fertilizers and microbial preparations can significantly increase soil pH and increase SOM, soil TN, AvN, AvP, and AvK [46,47].The long-term application of organic fertilizers can increase microbial biomass and enzyme activity, and improve the quantity and quality of SOM [48].Adding Bacillus and Pseudomonas to organic fertilizer can further improve soil enzyme activity and nutrient content [49].The improvement of soil fertility is due to the propagation of microorganisms in organic fertilizers, which can regulate the accumulation and circulation of soil nutrients [50].Organic fertilizer can improve different crops and different soils to some extent.The improvement of total soil nutrients by BF is not as good as that by OF, which may be due to the reproduction and fixation of microorganisms in BF which consume part of the organic matter and the nitrogen, phosphorus, and potassium.The increasing effect of BF in soil fertility due to AvP and AvK is equivalent to that of OF, and microorganisms play a very important role.Soil enzyme activity is very important, and this indicator contributes to revealing the mechanism of disease suppression after soil improvement with organic fertilizers [51].Organic fertilizers can improve the number of soil microorganisms and the availability of nutrients so that crops can be better absorbed [52].Many studies have manifested that the application of organic fertilizers can increase soil enzyme activity and soil microbial functional diversity [48,53].Meta-analysis indicated that the application of organic fertilizers could significantly increase soil bacteria by 5.94% compared with 100% CF, however the effect on soil fungi was not significant.The application of organic fertilizers can significantly increase soil urease by 22.32% compared with 100% CF (BF is not significant), and soil catalase by 17.68% (where BF is better than OF) (Figure 7).Studies have shown that in cotton drip irrigation systems, the combined application of organic and inorganic fertilizers has the best effect on the total scale of microbial communities, whereas organic fertilizers have the greatest impact on soil enzyme activities [54].Verstraete and Voets [55] showed that the application of animal manure plus green manure over a 7-year period substantially increased diphosphatase, urease, saccharase, and b-glucosidase activities.Compared with conventional fertilization, organic fertilizers and microbial preparations treated soil increased urease, phosphatase, sucrase and catalase activities by 86.3, 85.1, 46.6, and 33.5%, respectively.Furthermore, the number of bacteria and actinomycetes increased by 89.9 and 183.4%, respectively [45].The effect of BF on improving soil bacteria is not as good as that of OF, which is consistent with the result that the soil SOM of BF is not as good as that of BF because the reproduction and survival of microorganisms require certain nutrients provided by organic matter in the soil.In general, all kinds of organic fertilizers improved the physicochemical and biological properties of soil.The catalase and pH of BF were better than that of OF, while the Ec, bacteria, urease, and total nutrients were lower than that of OF.This may be related to the structure and quantity of microbial communities in BF, and the specific reasons need further study.

Effects of Organic Fertilizer Application on Tomato Yield
The results of the meta-analysis revealed that the application of organic fertilizers can increase the yield by 3.48% compared with 100% CF.BF can increase the yield by 14.15%, whereas OF have no significant effect on yield (Figure 8).Studies have shown that organic fertilizers can change soil microbial community structure after fumigation.Chemical fertilizers increased strawberry yield, and increased Fusarium and Phytophthora pathogen mortality.A significant increase in strawberry yield was positively correlated with increases in beneficial microorganisms such as Gemmatimonadetes, Firmicutes, Bacillus, and Flavisolibacter.Organic fertilizers can activate beneficial microorganisms in the soil after fumigation, promote soil health, and increase fruit yield [56].The significant impact of bio-organic fertilizers and chemical fertilizers on soil lies in the structure of soil microbial communities.Studies have shown that the application of organic fertilizers increases Ascomycota, which can promote the absorption of nutrient elements by plant roots and promote plant growth and development [57].Some studies have shown that fresh chicken manure can significantly improve soil microbial substrate-induced respiration and shorten the recovery time of soil beneficial microorganisms and increase taxonomic diversity [58].Studies have revealed that vermicomposting can produce more stable yields compared with chemical fertilizers.This can be attributed to the high proportion of degraded organic matter in vermicomposting, thus resulting in higher nutrient utilization compared with other organic amendments.Vermicomposting also contains humic acid, which can promote the release of cations and promote plant growth [59].Vermicomposting resulted in an increase in the concentration of nitrogen-fixing microorganisms in the soil, hence the increased N availability [30].In the production of pak choi, a combination of biological organic fertilizer and chemical fertilizer was used.The application of organic fertilizer could increase the yield, and the diversity and richness of the microorganisms were increased [60].Organic fertilizer application increased the soil microbial community's resistance to disturbance compared with chemical fertilization or no fertilization [61][62][63].This revealed that bio-organic fertilizers and common organic fertilizers have changed the community structure of soil microorganisms.The improvement methods of different organic fertilizers were different, and the community structure was related to the yield.Then soil microbial community structure interacts with crops, which affects the yield.The specific reasons for the impact need further mechanistic research.

Effects of Organic Fertilizer Application on Tomato Quality
The results of the meta-analysis showed that the application of organic fertilizers could significantly reduce fruit nitrate by 12.66%, and significantly increase fruit sugar by 4.79%, fruit lycopene by 4.80%, and fruit protein by 13.82% (Figure 10).OF showed significant effects on nitrate, sugar, lycopene, and protein, while BF only showed significant effects on protein.BF could not significantly improve the fruit quality, and it was speculated that it was related to significantly increasing the yield.In this case, the nutrient supply required by the crop was not sufficient, resulting in a lower quality than with OF.Studies have revealed that in bread wheat, grain yield is negatively correlated with its grain protein content.Quantitative trait locus (QTL) is intended to alleviate this relationship in genetic breeding [64].A higher 1000 grain weight was negatively correlated with quality characteristics [65].The meta-analysis revealed that the bio-organic fertilizer had significantly increased the tomato yield, but the effect was non-significant on its quality.It is evident from a study that the total contents of flavonoids, anthocyanin, and oxalic acid in strawberry fruits was higher for OF than for those in BF [66].The application of cattle manure (OF) on dragon's head (Lallemantia iberica (M.Bieb.)Fisch.and C. A. Mey), produced a higher quality essential oil content than vermicomposting (BF) [67].Similarly, the application of ordinary organic fertilizer increased total phenol, flavonoids, and DPPH antioxidant activity in Syrian cephalaria (Cephalaria syriaca L.), more than bioorganic fertilizer [68].It is evident from the previous studies that bio-organic fertilizers are not as good as organic fertilizers in improving the fruit quality of different crops, but this conclusion is not universal and varied accordingly, and was thus related to the type of crops and the quality of organic fertilizers.Moreover, there is a negative correlation between the yield and quality of different crops, but this negative correlation is not certain.The effect of BF on quality improvement is not as good as that OF, and the reasons need to be further studied.

Conclusions
Organic fertilizers can improve soil properties, tomato yield, and fruit quality.Bioorganic fertilizers have better effects on tomato yield, soil electrical conductivity, and soil catalase activity.Common ordinary organic fertilizers have better effects on tomato quality (nitrate, sugar, tomato red element) and soil total nitrogen, phosphorus, and potassium, and soil bacteria.Both bio-organic and ordinary organic fertilizer can improve the protein content of tomato and the pH of acidic and neutral soil, and increase soil organic matter and available phosphorus and potassium, but have no significant effect on soil ammonium nitrogen, nitrate nitrogen, and soil fungi.However, the mechanism of these effects needs to be further investigated.

Sustainability 2023 , 20 Figure 1 .
Figure 1.Trial sites for the application of organic fertilizers in global tomato cultivation (n = 124).

Figure 1 .
Figure 1.Trial sites for the application of organic fertilizers in global tomato cultivation (n = 124).

Figure 2 .
Figure 2. Soil conductivity and pH sample distribution number map, the red curve is the normal distribution fitting curve.Figure 2. Soil conductivity and pH sample distribution number map, the red curve is the normal distribution fitting curve.

Figure 2 .
Figure 2. Soil conductivity and pH sample distribution number map, the red curve is the normal distribution fitting curve.Figure 2. Soil conductivity and pH sample distribution number map, the red curve is the normal distribution fitting curve.

Sustainability 2023 , 20 Figure 3 .
Figure 3. Global effects of organic fertilizer application on soil electrical conductivity and pH.

Figure 3 .
Figure 3. Global effects of organic fertilizer application on soil electrical conductivity and pH.3.2.2.Meta-Analysis of Organic Fertilizer Application on Soil Nutrient Index The application of organic fertilizer significantly manipulates the nutrient index of the soil, and this change can be traced.Frequency statistics were performed on the response ratio (InR) of the soil's SOM, TN, TP, TK, NH 4 + -N, NO 3 − -N, AvP, and AvK, and fitted in the normal distribution.The fitting results are shown in Figure 4, whose R 2 values are 0.8966, 0.8492, 0.9577, 0.9678, 0.9185, 0.9415, 0.9481, 0.9067, and their P values are all <0.001.The fitting results were significant and have certain research significance.Sustainability 2023, 15, x FOR PEER REVIEW 8 of 20

Figure 4 .
Figure 4. Soil nutrient index sample distribution quantity map, the red curve is the normal distribution fitting curve.

Figure 4 .
Figure 4. Soil nutrient index sample distribution quantity map, the red curve is the normal distribution fitting curve.

Figure 5 .
Figure 5. Global effects of organic fertilizer application on soil nutrient index.

Figure 6 .Figure 6 .
Figure 6.The number of soil microorganisms and the distribution of enzyme activity samples, the red curve is the normal distribution fitting curve.

Figure 6 .
Figure 6.The number of soil microorganisms and the distribution of enzyme activity samples, the red curve is the normal distribution fitting curve.

Figure 7 .
Figure 7. Global effects of organic fertilizer application on soil microbial quantity and enzyme activity.

Figure 7 .
Figure 7. Global effects of organic fertilizer application on soil microbial quantity and enzyme activity.

Figure 8 .
Figure 8.The number of tomato yield samples and global effects of organic fertilizer application on tomato yield.

Figure 8 .
Figure 8.The number of tomato yield samples and global effects of organic fertilizer application on tomato yield.

Figure 9 .
Figure 9.The distribution quantity map of tomato quality index samples, the red curve is the normal distribution fitting curve.Figure 9.The distribution quantity map of tomato quality index samples, the red curve is the normal distribution fitting curve.

Figure 9 . 20 Figure 10 .
Figure 9.The distribution quantity map of tomato quality index samples, the red curve is the normal distribution fitting curve.Figure 9.The distribution quantity map of tomato quality index samples, the red curve is the normal distribution fitting curve.Sustainability 2023, 15, x FOR PEER REVIEW 12 of 20 2.46, and the slope of Figure 11D is 2.79).

Figure 10 .
Figure 10.Global effects of organic fertilizer application on tomato quality.

20 Figure 11 .
Figure 11.Regression analysis of yield after applying organic fertilizer, the straight line represents the fitting curve after one regression, and the dotted line is the 95% confidence interval.

Figure 11 .
Figure 11.Regression analysis of yield after applying organic fertilizer, the straight line represents the fitting curve after one regression, and the dotted line is the 95% confidence interval.
Fruit sugar was significantly positively correlated with fruit protein, soil Ec, TN, NO 3 − -N, and bacteria, and significantly negatively correlated with soil NH 4 + -N.Lycopene was significantly positively correlated with soil SOM, TN, NO 3 − -N, and AvK, and was significantly negatively correlated with soil NH 4 + -N.Protein was significantly positively correlated with soil SOM, and negatively correlated with Soil pH (6-8) and Soil nitrate nitrogen.Soil Ec was significantly positively correlated with Soil pH (<6), TN, TP, TK, NO 3 − -N, AvP, AvK, and urease, and significantly negatively correlated with Soil pH (6~8).pH (<6) was significantly positively correlated with Soil TN, TP, TK, and NH 4 + -N, and significantly negatively correlated with soil fungi and catalase.Soil pH (6~8) was significantly negatively correlated with soil SOM and AvP.Soil SOM was significantly positively correlated with Soil TN, AvP, AvK, and bacteria, and significantly negatively correlated with soil catalase.Soil TN was significantly negatively correlated with soil TP, TK, AvP, AvK, Bacteria, and Soil catalase.Soil TP was significantly positively correlated with Soil TK, AvP, and AvK.Soil TK was significantly positively correlated with Soil NO 3 − -N and fungi.Soil NH 4 + -N was significantly positively correlated with soil NO 3 − -N, and significantly negatively correlated with Soil fungi.Soil NO 3 − -N was significantly positively correlated with Soil AvK.Soil AvP was significantly positively correlated with Soil AvK.Soil AvK was significantly positively correlated with Soil catalase.Soil urease was significantly positively correlated with Soil catalase.Sustainability 2023, 15, x FOR PEER REVIEW 14 fungi.Soil NH4 + -N was significantly positively correlated with soil NO3 − -N, and sig cantly negatively correlated with Soil fungi.Soil NO3 − -N was significantly positively related with Soil AvK.Soil AvP was significantly positively correlated with Soil AvK AvK was significantly positively correlated with Soil catalase.Soil urease was sig cantly positively correlated with Soil catalase.

Figure 12 .
Figure 12.Correlation analysis of soil properties and tomato yield, fruit quality after applicati organic fertilizer.Red indicates positive correlation, blue indicates negative correlation, darker indicates stronger correlation, if the point is white and marked with *, it means that there overlap between the two datasets.

Figure 12 .
Figure 12.Correlation analysis of soil properties and tomato yield, fruit quality after application of organic fertilizer.Red indicates positive correlation, blue indicates negative correlation, darker color indicates stronger correlation, if the point is white and marked with *, it means that there is no overlap between the two datasets.

Table 1 .
Heterogeneity test of different indicators and analysis of differences between the groups.