The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the soil.This study focused on the effects of different...The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the soil.This study focused on the effects of different gravel contents on the water absorption characteristics and hydraulic parameters of stony soil.The stony soil samples were collected from the eastern foothills of the Helan Mountains in April 2023 and used as the experimental materials to conduct a one-dimensional horizontal soil column absorption experiment.Six experimental groups with gravel contents of 0%,10%,20%,30%,40%,and 50%were established to determine the saturated hydraulic conductivity(K_(s)),saturated water content(θ_(s)),initial water content(θ_(i)),and retention water content(θ_(r)),and explore the changes in the wetting front depth and cumulative absorption volume during the absorption experiment.The Philip model was used to fit the soil absorption process and determine the soil water absorption rate.Then the length of the characteristic wetting front depth,shape coefficient,empirical parameter,inverse intake suction and soil water suction were derived from the van Genuchten model.Finally,the hydraulic parameters mentioned above were used to fit the soil water characteristic curves,unsaturated hydraulic conductivity(K_(θ))and specific water capacity(C(h)).The results showed that the wetting front depth and cumulative absorption volume of each treatment gradually decreased with increasing gravel content.Compared with control check treatment with gravel content of 0%,soil water absorption rates in the treatments with gravel contents of 10%,20%,30%,40%,and 50%decreased by 11.47%,17.97%,25.24%,29.83%,and 42.45%,respectively.As the gravel content increased,inverse intake suction gradually increased,and shape coefficient,K_(s),θ_(s),andθ_(r)gradually decreased.For the same soil water content,soil water suction and K_(θ)gradually decreased with increasing gravel content.At the same soil water suction,C(h)decreased with increasing gravel content,and the water use efficiency worsened.Overall,the water holding capacity,hydraulic conductivity,and water use efficiency of stony soil in the eastern foothills of the Helan Mountains decreased with increasing gravel content.This study could provide data support for improving soil water use efficiency in the eastern foothills of the Helan Mountains and other similar rocky mountainous areas.展开更多
为提升贺兰山东麓葡萄园晚霜冻灾害精细化防御能力,利用2020—2023年4—5月贺兰山东麓葡萄园农田小气候站最低气温观测数据,分析葡萄园最低气温变化特征、晚霜冻发生频率和区域分布特征,并基于欧洲中期天气预报中心(European Centre for...为提升贺兰山东麓葡萄园晚霜冻灾害精细化防御能力,利用2020—2023年4—5月贺兰山东麓葡萄园农田小气候站最低气温观测数据,分析葡萄园最低气温变化特征、晚霜冻发生频率和区域分布特征,并基于欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)模式预报产品和宁夏地区格点气温实况,采用径向基函数(Radial Basis Function,RBF)神经网络算法,构建贺兰山东麓葡萄园最低气温和霜冻预报模型。结果表明:贺兰山东麓葡萄园轻霜冻最为普遍,其次是中霜冻,4月是霜冻发生的主要月份,东方裕兴酒庄霜冻出现最频繁,观兰酒庄霜冻最少,红寺堡产区是霜冻易发区。最低气温和霜冻预报检验结果显示,与ECMWF模式相比,RBF模型对贺兰、永宁和红寺堡产区的最低气温预报准确率提高,最高提升幅度达33.8%,平均绝对误差降低0.20~1.50℃。从单站霜冻预报看,RBF模型有明显优势,准确率普遍提升1.0%~14.0%,平均绝对误差降低0.04~0.37℃;从产区平均看,RBF模型对红寺堡产区霜冻预报准确率提高最多,达13.0%。在针对霜冻的实例分析中,RBF模型预报效果更优,特别是对中霜冻预报优势明显,相比ECMWF模式准确率提升25.0%~50.0%,平均绝对误差降低1.80~2.10℃。展开更多
基金funded by the National Natural Science Foundation of China(32360321)the Natural Science Foundation of Ningxia Hui Autonomous Region,China(2023AAC03046,2023AAC02018)the Ningxia Key Research and Development Project(2021BEG02011).
文摘The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the soil.This study focused on the effects of different gravel contents on the water absorption characteristics and hydraulic parameters of stony soil.The stony soil samples were collected from the eastern foothills of the Helan Mountains in April 2023 and used as the experimental materials to conduct a one-dimensional horizontal soil column absorption experiment.Six experimental groups with gravel contents of 0%,10%,20%,30%,40%,and 50%were established to determine the saturated hydraulic conductivity(K_(s)),saturated water content(θ_(s)),initial water content(θ_(i)),and retention water content(θ_(r)),and explore the changes in the wetting front depth and cumulative absorption volume during the absorption experiment.The Philip model was used to fit the soil absorption process and determine the soil water absorption rate.Then the length of the characteristic wetting front depth,shape coefficient,empirical parameter,inverse intake suction and soil water suction were derived from the van Genuchten model.Finally,the hydraulic parameters mentioned above were used to fit the soil water characteristic curves,unsaturated hydraulic conductivity(K_(θ))and specific water capacity(C(h)).The results showed that the wetting front depth and cumulative absorption volume of each treatment gradually decreased with increasing gravel content.Compared with control check treatment with gravel content of 0%,soil water absorption rates in the treatments with gravel contents of 10%,20%,30%,40%,and 50%decreased by 11.47%,17.97%,25.24%,29.83%,and 42.45%,respectively.As the gravel content increased,inverse intake suction gradually increased,and shape coefficient,K_(s),θ_(s),andθ_(r)gradually decreased.For the same soil water content,soil water suction and K_(θ)gradually decreased with increasing gravel content.At the same soil water suction,C(h)decreased with increasing gravel content,and the water use efficiency worsened.Overall,the water holding capacity,hydraulic conductivity,and water use efficiency of stony soil in the eastern foothills of the Helan Mountains decreased with increasing gravel content.This study could provide data support for improving soil water use efficiency in the eastern foothills of the Helan Mountains and other similar rocky mountainous areas.
文摘为提升贺兰山东麓葡萄园晚霜冻灾害精细化防御能力,利用2020—2023年4—5月贺兰山东麓葡萄园农田小气候站最低气温观测数据,分析葡萄园最低气温变化特征、晚霜冻发生频率和区域分布特征,并基于欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)模式预报产品和宁夏地区格点气温实况,采用径向基函数(Radial Basis Function,RBF)神经网络算法,构建贺兰山东麓葡萄园最低气温和霜冻预报模型。结果表明:贺兰山东麓葡萄园轻霜冻最为普遍,其次是中霜冻,4月是霜冻发生的主要月份,东方裕兴酒庄霜冻出现最频繁,观兰酒庄霜冻最少,红寺堡产区是霜冻易发区。最低气温和霜冻预报检验结果显示,与ECMWF模式相比,RBF模型对贺兰、永宁和红寺堡产区的最低气温预报准确率提高,最高提升幅度达33.8%,平均绝对误差降低0.20~1.50℃。从单站霜冻预报看,RBF模型有明显优势,准确率普遍提升1.0%~14.0%,平均绝对误差降低0.04~0.37℃;从产区平均看,RBF模型对红寺堡产区霜冻预报准确率提高最多,达13.0%。在针对霜冻的实例分析中,RBF模型预报效果更优,特别是对中霜冻预报优势明显,相比ECMWF模式准确率提升25.0%~50.0%,平均绝对误差降低1.80~2.10℃。