# Changes in Soil Moisture Improved by High-Performance Ester Materials under Dry-Wet Cycles
## 3 Results and Discussion
### Rules of Soil Improvement Using High-Performance Ester Materials under Dry-Wet Cycling Conditions  
Dry-wet cyclesweaken the cohesion of soil, reducing the bonding force between soil particles. This leads to a deterioration of soil particle structure and a reduction in aggregation, which consequently leads to a decrease in the soil's water holding capacity and EC. As shown in Figure 7, high-performance ester materials respond to the dry-wet cycle in terms of soil water holding capacity. It can be seen that as the dry-wet cycle progresses, the soil's water holding capacity gradually weakens and then levels off, stabilizing around the 10 th time. After various dry-wet cycles, the improvement effect of the ester materials weakened, but the test groups with high-performance ester materials always showed stronger water holding capacity than the control group without materials, and the material still performed an improvement effect. As the number of dry-wet cycles increased, the improvement in water holding capacity becomes more pronounced. Water-retaining materials improve the soil's water holding capacity through their excellent water absorption and storage performance, which means that the soil still has sufficient moisture content after multiple wet-dry cycles. Adhesive materials enhance the bonding force between soil particles, allowing the soil to maintain a stable aggregate structure after multiple dry-wet cycles.  
The dry-wet cycle reduces soil cohesion, resulting in a decrease in the number of large soil aggregates, which in turn reduces organic matter in the soil and leads to a decrease in EC. As shown in Figure 8, the response of high-performance ester materials to dry-wet cycles in improving soil EC has been demonstrated. It was observed that after multiple dry-wet cycles, the improvement effect of the ester materials on soil EC weakened. As the dry-wet cycles continued, the soil EC gradually weakened and then stabilized, reaching a stable state after about 10 cycles. However, when comparing the test group with added materials and the control group without added materials after the influence of dry-wet cycles, high-performance ester materials still showed an improvement effect; the EC of the test group with added materials was higher than that of the control group. Adhesive materials can increase the number of large soil aggregates [10], restore a good aggregate structure to the soil, weaken the impact of dry-wet cycles on the soil's structure, enhance the soil's ability to store nutrients, increase the soil's organic matter content, and thus increase the soil's EC. Soil's EC is also closely related to soil's moisture; the more water is dissolved in the soil, the higher the EC.  
Figure 7: _Cont._Figure 8: \(Cont\).  
Figure 7: Response of high-performance ester materials to dry–wet cycles: Soil water holding capacity improvement: (**a**) CK and test group 1–9: Two polymer materials were added to the soil sample; (**b**) CK and test group 10–15: Soil sample added with one polymer material.  
Due to the effect of high-performance ester materials, the soil had undergone multiple dry-wet cycles and still had sufficient moisture and EC. Adequate water holding capacity is the key to effective plant growth and development, while EC reflects the fertility level of the soil. Therefore, we can infer that high-performance ester materials can improve the soil's ecological performance.