# Changes in Soil Moisture Improved by High-Performance Ester Materials under Dry-Wet Cycles
## 3 Results and Discussion
### The Improvement Effect of High-Performance Ester Materials on Soil Water Holding Capacity Soil EC  
Soil's EC also impacts plant growth. High-performance ester materials can improve soil's EC, as shown in Figure 6 for the improvement effect of the ester materials on soil EC. The results demonstrate that for soil EC in the test groups with different material ratios under various dry-wet cycles, evidently the high-performance ester materials improved the soil EC. Throughout all dry-wet cycles, the EC of the test group with added materials was higher than that of the CK group without added materials. In test groups 1-9 with added materials, it was found that the soil's EC increased with the increase of water-retaining materials, indicating that water-retaining materials played a key role in improving soil EC, which is consistent with the trend of improving soil moisture capacity. Soil EC is closely related to soil moisture. With the increase of adhesive materials, the soil's EC showed a slow increasing trend, with a smaller increase compared to the increase brought by water-retaining materials. Combining the observation and analysis from test groups 10-12 (with only water-retaining materials added) and groups 13-15 (with only adhesive materials added), it can be concluded that both water-retaining materials and adhesive materials can improve soil EC, but that the effect of adhesive materials is smaller than that of water-retaining materials.  
To explore the role of high-performance ester materials in improving soil's EC, variances in the data from the test's result were analyzed. Results from the 0 th, 4 th, 8 th, and 20 th dry-wet cycle tests from test groups 1-9 (with two materials added) were selected for variance analysis, with the added amount of adhesive and water-retaining materials as independent variables and the soil sample's EC as the dependent variable. For variable water-retaining materials, analysis of the F-test results from the data of the 0 th, 4 th, 8 th, and 20 th dry-wet cycle tests showed that the significance \(p\)-values were 0.003, 0.003, 0.008, and 0.016, respectively, which were less than 0.05, implying that water-retaining materials can significantly affect soil's EC. For variable adhesive materials, F-test results analysis of the data from the 0 th, 4 th, 8 th, and 20 th dry-wet cycle tests showed that the significance \(p\)-values were 0.003, 0.041, 0.004, and 0.046, respectively, all less than 0.05, showing that water-retaining materials had a significant impact on the EC of the soil samples. By comparing the \(p\) values of variables water-retaining materials and adhesive materials, the analysis revealed that overall, the \(p\) value of water-retaining materials was smaller, and their impact on soil EC was more significant than that of adhesive materials.  
From the analysis of the test results above demonstrate that high-performance ester materials can significantly improve soil's EC under various dry-wet cycles. Both water-retaining materials and adhesive materials play a major role in this improvement, but the influence of water-retaining materials is greater.  
Figure 6: Improvement effect of high-performance ester materials on soil EC: (**a**) CK and test groups 1–9: Two polymer materials were added to the soil sample; (**b**) CK and test groups 10–15: Soil sample added with one polymer material.