黄土丘陵区带状柠条锦鸡儿林地深层土壤干化及根系分布

Deep soil desiccation and root distribution of belted Caragana korshinskii forest in loess hilly region

针对黄土丘陵区带状柠条锦鸡儿人工林地根系、土壤水分特征及深层土壤干化研究薄弱问题,以宁夏南部山区20 a雨养带状人工柠条锦鸡儿林地为研究对象,选取相似的旱作农田为对照,对0~1000 cm深度土壤水分、柠条锦鸡儿根系垂直分布及其相关性进行分析。结果表明:(1)20 a人工柠条锦鸡儿林地0~1000 cm深度土壤干化,柠条锦鸡儿林地带内和带间土壤水分含量低于农田;0~1000 cm土层带内土壤水分含量较带间降低1.46%。(2)在300~1000 cm土层范围内,20 a人工柠条锦鸡儿林地出现了不同的亏缺程度与干燥化程度,带间、带内水分有效性分别为0.21和0.02,供水系数平均值分别为0.49和0.33。(3)柠条锦鸡儿林地根系主要集中在0~80 cm土层,0~80cm土层带间、带内根干重分别占总根重的46.33%和45.56%,根表面积密度分别占总根表面积密度的66.58%和63.51%,根长密度分别占总根长密度的59.54%和58.45%。该研究对于深入了解半干旱黄土区人工柠条锦鸡儿林地根系、水分具有积极意义。

To explore the deep water status and root distribution of artificial rainfed planting Caragana korshinskii forest in southern Ningxia of China,the 20-year rainfed strip planting C.korshinskii forest was chosen as the research object,a similar farmland for control was selected,and a 0-1000-cm depth of soil moisture,vertical distribution of root,and correlation were analyzed.Soil moisture and root systems were investigated in the center of the C.korshinskii and farmland.The soil drying method was used to determine the soil moisture content,and the root-drill sampling method was used to investigate the root system.The results showed the following:(1)Deep soil desiccation was determined in 0-1000 cm soil layers for the 20-year C.korshinskii forest.Soil water content for the interband and intra-band of C.korshinskii forest was lower than farmland.Compared with the interband soil water,the intra-band soil moisture content was reduced by 1.46%in the 0-1000 cm soil layer.(2)In the range of 300-1000 cm soil layer,the 20-year artificial C.korshinskii appeared in different water deficiency states and soil desiccation.Soil moisture availability for the interband and intra-band were 0.21 and 0.02 and the soil water supply coefficient were 0.49 and 0.33,respectively.(3)C.korshinskii roots mainly distributed in the 0-80 cm soil layer,accounting for 46.33%and 45.56%of the total root weight for interband and intra-band dried roots,respectively.The root surface area density accounted for 66.58%(interband)and 63.51%(intra-band)of the total root surface area density,and root length density accounted for 59.54%(interband)and 58.45%(intraband)of the total root length density.This study has positive significance for in-depth understanding of root systems,water content,and sustainable management of artificial vegetation in semiarid loess areas.