## 3 Results
### Overall Effect of Organic Fertilizer on Tomato Yield and Quality
The percentage increases were 14.21%, 11.24%, and 8.43% in plant organic fertilizer, animal organic fertilizer, and mixed organic fertilizer, respectively. Other organic fertilizer had no effect, which was 5.73%. Plant organic fertilizer significantly improved tomato soluble solids. At a pH \(<\) 7, the percentage increase of TSS was 16.67%, whereas at a pH \(>\) 7, the percentage increase was 12.52% (Figure 5d). In conclusion, the application of organic fertilizers on acidic soil significantly improved the tomato soluble solids more than that on alkaline soil (Figure 5e). The soluble solid content of tomato cultivated in a greenhouse is higher (16.81%) than that cultivated in the field (4.98%). There is a statistical difference between them. Figure 3: Relationship between soil organic matter, total soil nitrogen, and tomato quality: TSS (**a**), SS (**b**), SAR (**c**), VC (**d**), and nitrate (**e**); TSS (**f**), SS (**g**), SAR (**h**), VC (**i**), and nitrate (**j**). Effect of Organic Fertilizer Combined with Soil Organic Matter, Total Soil Nitrogen, and Organic-Fertilizer Type on SS and SAR  
The percentage change of organic fertilizers on the soluble sugar of tomato increased significantly when the organic matter was <20 g\(\cdot\)kg\({}^{-1}\); the percentage change of organic fertilizers on the soluble sugar of tomato increased by 60.35% (Figure 6a). The percentage change was \(-\)18.09% when the organic fertilizers were \(\geq\)20 g\(\cdot\)kg\({}^{-1}\). When the total soil nitrogen was 0.1-1 g\(\cdot\)kg\({}^{-1}\) and >1 g\(\cdot\)kg\({}^{-1}\), organic fertilizers had positive effects on tomato soluble sugar, and the percentage changes were 51.86% and 30.53%, respectively (Figure 6b). Both plant organic fertilizers and animal organic fertilizers had positive effects on tomato soluble sugar, and the respective percentage changes were 48.04% and 48.02%; thus, the  
Figure 4: Organic fertilizers combined with soil organic matter (**a**), total soil nitrogen (**b**), type of organic fertilizers (**c**), soil pH (**d**), and cultivation type (**e**) on tomato yield percentage changes. Points represent the mean effect, while bars represent 95% confidence intervals. The numbers on the right side of the confidence intervals represent the sample sizes. AOF, animal organic fertilizer; MOF, mixed animal-and-plant organic fertilizer; POF, plant organic fertilizer; OOF, other organic fertilizer. confidence intervals overlap (Figure 6c). However, there was no significant difference between mixed organic and other types of organic fertilizers in the percentage changes in tomato soluble sugar. The confidence intervals overlapped, and percentage changes were 25.03% and 18.14%. When the pH was \(\geq\)7, organic fertilizers increased tomato soluble sugar with a percentage change of 20.86%, but there was no significant difference (Figure 6d). The increase of soluble sugar in tomatoes with a pH \(<\) 7 was significantly different, with a percentage change of 84.52%. Both cultivation types had positive effects on the soluble sugars. The application of organic fertilizers in facility cultivation had significant effects on tomato soluble sugar, with a percentage change of 46.13%, but no significant effect was observed in the open field, with a percentage change of 29.82% (95% CI: \(-\)3.43% to 74.53%) (Figure 6e). As can be seen from the figure, compared with no application of organic fertilizers, the cultivation type, organic-fertilizer type, soil organic matter, soil pH, and total soil nitrogen had no significant influence on the tomato sugar/acid ratio under the increased application of organic fertilizers compared to no application of organic fertilizers (Figure 7). Figure 5: Organic fertilizers combined with soil organic matter (**a**), total soil nitrogen (**b**), type of organic fertilizers (**c**), soil pH (**d**), and cultivation type (**e**) on tomato TSS (total soluble solids) percentage changes. Points represent the mean effect, while bars represent 95% confidence intervals.