Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science submitted time 2023-03-13 Cooperative journals: 《干旱区研究》
Abstract： A thorough investigation of the distribution of natural Populus euphratica, tree growth, regeneration characteristics, soil types, and factors in the Hexi Corridor was conducted. The distribution and regeneration status of natural P. euphratica in the Hexi Corridor, as well as its relationship with soil factors, were then examined. The results showed that: (1) Natural P. euphratica forests in the Hexi Corridor were mainly distributed in riparian terraces, ancient river terraces and the edge of oasis cultivated land in the lower reaches of Shule River, Black River, and Shiyang River. There are four main types of forest land: abandoned land, the land around cultivated fields and irrigation canals, land along the current river course, and land among ancient river course and Gobi low-lying land. (2) The growth status, age structure, and seedling regeneration of P. euphratica in the land around cultivated fields and irrigation canal, land along the current river course are better than those of the abandoned land, and among ancient river course and Gobi low- lying land. In terms of the number of renewed seedlings per unit area, the land around the cultivated field and irrigation canal was the largest, with an average value of 22.13, followed by abandoned cultivated land (20.92), land along the current river course (10.50), and among ancient river course and Gobi low- lying land (1.33). (3) Different types of P. euphratica forests have different soil factor contents: (i) Available P: In the 0-20 cm soil layer, the soil available phosphorus showed the trend as; land along the current river course < land among ancient river course and Gobi low- lying land < abandoned land, land around cultivated field and irrigation canal cultivated land; in the 20-40 cm soil layer, land along the current river course had significant less available phosphorus than the other three types of forest land (all P < 0.05); (ii) Moisture content was higher in the land around cultivated fields and irrigation canals, and land along the current river course than in abandoned land, land among ancient river course and Gobi low-lying land (all P < 0.05); (iii) In comparison to the other three types of forest land, abandoned land has significantly lower soil conductivity between the 0-20 cm and 20-40 cm soil layers (P < 0.05). There was no significant difference in the contents of total N and organic matter among different types of forest land (P > 0.05) and in the 40-60 cm soil layer, land among the ancient river course and Gobi low- lying land was significantly higher (P < 0.05). Except for the coarse sand in the 0-20 cm soil layer, the soil clay particles, silt particles, and coarse particles in the land around the cultivated field and irrigation canal performed significantly higher than those in the other three types of forest land (P < 0.05). (4) The contents of soil moisture and available P were positively correlated with the middle and young age of P. euphratica and the number of seedlings (P < 0.05). (5) To encourage the sustainable development of P. euphratica forest, improve forest management and protection, timely thinning, removal of branches and dieback, thinning, and irrigation.
Subjects: Environmental Sciences, Resource Sciences >> Other Disciplines of Environmental Sciences, Resource Sciences submitted time 2021-03-02 Cooperative journals: 《干旱区研究》
Abstract：选取不同年限退/弃耕地（退耕1 a、2 a、4 a、8 a、13 a、20 a、30 a、40 a和CK）为研究对象，采用时空替代法，分析了不同年限退/弃耕地植被群落特征和土壤理化性质及其相关性。结果表明：（1）石羊河下游青土湖退/弃耕地40 a的植被恢复过程中，9个样方共出现15科29属43种植物，退/弃耕地物种构成表现为：多数种属于少数科、少数种属于多数科。植被演变分为：一年生草本和多年生植物快速生长期（1~2 a），一年生草本向多年生草本演变期（2~8 a），多年生草本向灌木演变期（8~20 a）和以灌木为主的稳定期（20~40 a）；（2）随退耕年限增加，土壤含水量呈先减小后增加最后波动式减小趋势，上层土壤含水量高于下层土壤含水量。各样方比例最大是细砂粒，粉粒次之，比例最小的是粗砂粒和黏粒，随退耕年限的变化，各粒径占比变化不大；（3）随退耕年限增加，土壤全氮和有机质均呈下降趋势，速效钾含量呈先增加后减小趋势，速效磷含量呈先减小后增加再减小趋势，表聚现象明显；（4）植被群落演替与土壤理化性质具有密切相关性。Margalef丰富度指数与土壤全氮和有机质呈极显著正相关关系，Shannon多样性指数与土壤容重和细砂粒呈显著的正相关关系，与土壤黏粒和粉粒呈显著负相关关系。退耕第4 a是青土湖退/弃耕地在恢复治理过程中关键时期。
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2020-04-26 Cooperative journals: 《干旱区研究》
Abstract：通过对民勤绿洲外围4种不同立地类型黑果枸杞群落物种组成、生长特征、土壤因子等的调查，分析不同立地类型土壤因子对黑果枸杞生长的影响。结果表明：① 不同立地类型黑果枸杞群落物种结构简单，共出现12科24属28种，存在多个单属单科单种现象，多为适应干旱盐碱化的藜科、蒺藜科植物，无乔木和高大灌木，黑果枸杞在不同立地类型中优势地位明显。② 黑果枸杞群落丰富度指数砾石地高于盐碱地、覆沙地及固定或半固定沙丘地（P＜0.05）；多样性指数砾石地高于盐碱地，盐碱地高于覆沙地及固定或半固定沙丘地（P＜0.05）。③ 不同立地类型黑果枸杞密度表现为：盐碱地＞覆沙地＞固定或半固定沙丘地＞砾石地。株高表现为：固定或半固定沙丘地＞盐碱地＞覆沙地＞砾石地。冠幅表现为：固定或半固定沙丘地＞盐碱地＞砾石地＞覆沙地。④ 土壤速效钾、有效磷、全磷及有机质含量均为盐碱地显著高于其他3个立地类型（P＜0.05），全钾、全氮含量在4种不同立地类型之间差异性不显著（P＞0.05）。不同土层中土壤因子变化规律不同。⑤ 土壤水分随土层深度的增加变化趋势不同，砾石地和固定或半固定沙丘地中土壤含水率随土层深度的增加而增加，覆沙地随土层深度的增加呈现波动变化，盐碱地随土层深度的增加变化不大。⑥ 黑果枸杞的生长状况和形态学特征株高、冠幅等受土壤水分、土壤氮、磷、钾及有机质等土壤因子的影响和制约，且10~20 cm土层深度土壤因子影响最为密切。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2020-01-02 Cooperative journals: 《干旱区研究》
Abstract： 在样地调查的基础上，结合相邻格子取样方法，采用扩散系数（C）、丛生指标（I）、负二项参数(K)、聚块性系数（Ca）、平均拥挤指标（m*）、聚集度指标（G）、Moristia指数（ ）、Green指数（IG）等8个指标，对石羊河下游不同立地类型黑果枸杞种群分布格局、聚集强度进行了研究，结果表明：沙地和盐碱地黑果枸杞个体数量较多，聚集程度相对较高，砾石和固定半固定沙地黑果枸杞的个体数量较少，聚集程度相对较低；盐碱地和沙地黑果枸杞种群呈现聚集分布，固定半固定沙地和砾石样地相对于沙地和盐碱地的聚集程度有所减弱，有一定的随机趋势；不同发育阶段的黑果枸杞种群格局类型总体呈现聚集分布的特点，随着龄级的增大，黑果枸杞种群分布格局表现出由聚集向均匀分布的变化趋势。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-09 Cooperative journals: 《干旱区研究》
Abstract： 通过测定石羊河下游民勤绿洲外围4个不同立地类型黑果枸杞群落植被特征和黑果枸杞株数、株高、冠幅等生物学特征，以及黑果枸杞分布格局的点坐标，采用空间点格局分析方法中的Ripley’s K函数，分析了民勤绿洲外围不同立地类型上黑果枸杞空间分布格局。结果表明：① 4个不同立地类型中植被物种数为：砾石地﹥盐碱地﹥固定或半固定沙丘地、覆沙地，植物群落结构比较简单，存在多个科单属单种现象。② 黑果枸杞株数在盐碱地中最多，覆沙地次之，固定或半固定沙丘地和砾石地中最少；而平均株高由高到低依次是固定或半固定沙丘地、盐碱地、覆沙地、砾石地；平均冠幅分布与平均株高类似。③ 在4个样地中，固定或半固定沙丘地和砾石地中的黑果枸杞呈现聚集分布；覆沙地中，黑果枸杞在较小尺度（0.2～0.5 m）呈现聚集分布，在较大尺度（1.5～2.5 m）呈现随机分布；盐碱地中，黑果枸杞种群表现为完全的随机分布。
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