To establish the Qiannian Xiulin (Millennium Forest of Xiong’an) that closely resembles a natural forest and is stable and self-adjusting, this study utilized soil precipitation and soil moisture data from 32 weather stations and the Qiannian Xiulin Regional Observation Station in Xiong’an New Area, Hebei Province. Machine learning and mathematical analysis methods were employed to investigate the change pattern of soil moisture content in the Qiannian Xiulin. The results indicate that the soil moisture content of the Qiannian Xiulin in Xiong’an is significantly influenced by the monsoon climate and exhibits distinct seasonal fluctuations. Specifically, soil moisture content increases slightly after soil thawing from January to March, gradually decreases from March to June, and reaches the lowest point in June. After June, it shows an upward trend, reaching the maximum in August, and then decreases again after September. The relative humidity of the surface soil at a depth of 0–10 cm in Qiannian Xiulin is positively correlated with precipitation, while the change pattern of relative soil humidity and precipitation in 20–30 cm and 30–50 cm soil layers are not obvious. There are differences in the impact of precipitation intensity on relative soil moisture in different soil layers. Significant changes in soil moisture will only occur when the daily precipitation exceeds 20 mm. The soil moisture content at these weather stations is consistent with the field observation data of Qiannian Xiulin. This study provides scientific soil moisture change rules for artificial planting management of the Qiannian Xiulin.

Xiong’an New Area, Qiannian Xiulin (Millennium Forest of Xiong’an), soil moisture content, soil relative humidity, seasonal variation, spatial distribution

为了营造近似自然林、具有自我调节能力的“千年秀林”, 利用千年秀林观测站样地实测土壤水分数据, 对照河北雄安新区32个气象站气象数据, 采用机器学习和数理统计方法, 研究雄安新区千年秀林的土壤含水量变化规律, 得到如下结果。1) 雄安新区千年秀林土壤含水量受季风气候的影响显著, 存在明显的季节性波动。1—3月土壤解冻后, 土壤含水量小幅度升高, 3—6月逐步下降, 6月降到最低; 6月以后呈现上升的趋势, 8月达到年际最高; 9月之后有下降的趋势。2) 千年秀林0~10 cm表层的土壤相对湿度与降水量显著正相关, 20~30 cm和30~50 cm土层的土壤相对湿度与降水量之间变化规律不明显。3) 降水强度对不同土层土壤相对湿度的影响存在差异, 当日降水量超过20 mm时, 土壤湿度才会出现显著的变化。4) 雄安新区气象站土壤水分含量数据与千年秀林实地观测数据的变化规律基本上一致。研究结果可为千年秀林的植树管理提供水分变化的科学依据。