## 4 Discussion
### The Role of Perennial Sweet Pea in Soil and Water Conservation  
Culturing perennial sweet peas has been shown to significantly impact soil moisture content, primarily due to their dense vegetation cover. One of the fundamental mechanisms through which vegetation influences soil moisture is the reduction of ground-level evaporation [38]. The abundant foliage and vigorous growth of perennial sweet peas create a protective canopy over the soil surface, reducing direct exposure to sunlight and wind. This shading effect is pivotal in diminishing the soil evaporation rate, consequently contributing to maintaining higher levels of soil re [39]. Furthermore, the presence of perennial sweet peas facilitates the capture and retention of rainwater within the soil profile. The plant's canopy intercepts and slows down raindrops, allowing more water to infiltrate the soil rather than running off, increasing soil moisture [18; 19]. Another critical factor contributing to soil moisture retention is the efficient utilization of soil water by the deep root system of perennial sweet peas. Their extensive root network can tap into water resources that are typically beyond the reach of shallower-rooted plants, effectively minimizing competition for soil moisture [39]. While perennial sweet peas enhance soil moisture content, it is essential to note that the moisture levels gradually recede over time. This decline can be attributed to plant transpiration and soil evaporation [39; 40; 41]. Dynamic fluctuations  
Figure 6: The coverage of four-year-old perennial sweet peas, encompassing (**a**) the impact of two distinct planting methods, strip seeding and hole seeding, on the coverage of perennial sweet peas and (**b**) the vegetation recovery coverage of perennial sweet peas following harvesting. in soil moisture in perennial sweet pea plots reveal that plants actively transpire water through their leaves and stems. As soil moisture is exposed to atmospheric conditions, a gradual decrease in soil moisture occurs [42; 43]. Nevertheless, this decline is generally slower compared to bare ground plots (CK) due to the initial moisture accumulation and the overall moisture-conserving properties of the perennial sweet pea ecosystem. These findings underscore the potential benefits of incorporating perennial sweet peas into land management strategies to conserve soil moisture. The hygroscopic properties of perennial sweet pea leaves and litter play a pivotal role in soil and water conservation. During specific key phenological stages, the leaf's moisture-absorbing characteristics enable the plant to effectively capture water vapor from the air, particularly during periods of high humidity or dew formation, further enhancing its ability to capture and retain water resources within the canopy [18; 19]. These attributes contribute to the mitigation of soil erosion, improvement of soil structure, and enhancement of overall resilience in water-limited ecosystems. Moreover, the leaf litter layer beneath the canopy of perennial sweet peas serves as a reservoir for capturing moisture [6; 16; 17]. This accumulated water gradually infiltrates the soil, thereby increasing soil moisture content and augmenting the overall water storage capacity of the ecosystem. These mechanisms hold significant importance in soil and water conservation and broader watershed management strategies, highlighting the multifaceted benefits of perennial sweet peas in sustainable land management practices. The correlation between fallen leaf accumulation and improved rainfall interception underscores the intricate interplay between vegetation and litter, collectively sustaining water resources [44]. Under heavy rainfall, the four-year-old perennial sweet pea trial area effectively intercepts rainwater and reduces runoff, surpassing the runoff reduction capabilities of mature natural vegetation.