Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： In order to reveal the effects of soil microbial film sand fixation on photosynthetic and fluorescence characteristics of psammophyte seedlings, Ammopiptanthus mongolicus and Astragalus laxmannii seedlings were selected. Pot experiment with different application methods (spray, mix) and application amount (0, 1, 3, 5, 7 and 10 g kg -1). The characteristics of plant gas exchange and chlorophyll fluorescence after soil microbial biofilm formation were analyzed. The results show that: (1) When the application amount of bacterial was greater than 3 g·kg-1, the hardness, thickness of the consolidated layer and soil urease and sucrase activities were significantly higher than those of the control group (P<0.05). (2) The net photosynthetic rate of Astragalus laxmannii in 3-7 g·kg-1 treatment was significantly higher than that of the control (P<0.05). And the transpiration rate, net photosynthetic rate and intercellular CO2 concentration were significantly higher than those of Ammopiptanthus mongolicus (P<0.05). (3) The Fv/Fm of Astragalus laxmannii treated with more than 5 g kg-1 was significantly higher than that of the control group (P < 0.05). Except for 3 g kg-1 treatment, the Fv/Fm and QP of Ammopiptanthus mongolicus were higher than those of Astragalus laxmannii. (4) Soil properties, photosynthetic gas exchange and chlorophyll fluorescence were partially mediated models. The change of soil characteristics can directly affect the chlorophyll fluorescence characteristics of Ammopiptanthus mongolicus and Astragalus laxmannii. The soil microbial film increased the hardness, thickness of the consolidated layer by 3.84% and 152.85% on average, and the activities of catalase, urease and sucrase were increased by 93.37%, 170.68% and 256.03% on average. By improving soil quality and stomatal conductance of leaves, the photosynthetic efficiency and capacity of the two plants were enhanced. The net photosynthetic rate and Fv/Fm were increased by 28.48% and 0.84% respectively.
Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： To reveal the soil bacterial community structure and its effects on Cyperus esculentus, affected bydifferent irrigation and salinity treatments in the Qian Gorlos Irrigation District, a random plot samplingexperiment was conducted using two-factor, three-level (irrigation level: 50%, 70%, and 100% standard irrigation quota;salt level: control group, mild salinity stress, and moderate salinity stress). Comparative analysis of soil bacterialcommunity characteristics in C. esculentus cropland under different irrigation and salinity treatments was performed.Simultaneously, the molecular ecological network of soil bacteria was constructed to determine the keystone species andits interrelationship with C. esculentus growth. Results showed that (1) The dominant phyla of soil bacteria in C.esculentus cropland were Proteobacteria (22.85% ± 3.80%), Acidobacteriota (20.02% ± 3.21%), and Actinobacteriota(18.85% ± 2.41%). The dominant genera were RB41, Sphingomonas, and Rubrobacter. Bacterial alpha diversity differedinsignificantly under different irrigation or salinity treatments (P > 0.05). With increasing irrigation, the relativeabundance of Proteobacteria gradually increased, whereas that of RB41 gradually decreased. The same trend wasobserved with increasing salinity stress. (2) The co-existence relationship between bacterial species was stronger in 100%standard irrigation quota treatments, with a positive correlation rate of 78.05%. Additionally, the degree of interactionsand tightness of connections between bacterial species was highest at 50% standard irrigation quota treatments. Thehighest ecological network complexity and degree of interactions among bacterial communities were found in controlgroup soils, and stronger co-existence relationships among bacterial species were found in moderate salinity soils, with apositive correlation rate of 75.31%. (3) The number of keystone species increased with increasing irrigation. Additionally,the RB41 genus appeared under 70% and 100% standard irrigation quota treatments. Significant differences wereobserved in keystone species under different salinity stresses. At an S2 salinity gradient, the number of keystone speciesreached a maximum, with the emergence of the dominant genera RB41 and Lysobacter. The keystone species wereRubrobacter, RB41, Dongia, Steroidobacter, Nitrospira, Lysobacter, and Luteolibacter. (4) Variations in irrigationsignificantly affected plant height, crown size, number of tillers, above-ground dry weight, carboxylase activity, proline,and superoxide dismutase activities of C. esculentus plants (P < 0.05). Changes in salt application significantly affectedplant height, above- ground dry weight, abscisic acid, soluble sugar, peroxidase activity, and malondialdehyde in C.esculentus (P < 0.05). The final screening was performed to conclude that Lysobacter, Nitrospira, Lysobacter, Dongia,RB41, Steroidobacter, and Luteolibacter were significantly associated with the growth and physiological traits of C.esculentus (P < 0.05). The soil bacterial community composition, molecular network, and keystone species were changedas a result of different irrigation or salt treatments, and keystone species were significantly associated with the growth ofC. esculentus. This improved information contributes to a better understanding of the soil bacterial community structureand its ecological function in C. esculentus cropland and provides a theoretical basis for adaptive planting and stable andhigh yield of C. esculentus.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2020-11-20 Cooperative journals: 《干旱区地理》
Abstract：为揭示科尔沁沙地不同林龄沙地樟子松人工林对风沙土粒径分布特征的影响，以中龄、近熟 和成熟沙地樟子松人工林风沙土为研究对象，以裸沙地风沙土为实验对照，采用激光衍射技术测定土壤样品粒度组成，计算分析土壤粒度参数特征，绘制土壤粒配曲线。结果显示：（1）科尔沁沙地樟子松人工林风沙土以砂粒为主，其次是粉粒，黏粒含量最少。随林龄的增长，土壤黏粒、粉粒含量呈增加趋势，砂粒含量呈减少趋势。裸沙地风沙土砂粒含量多高于同层林地土壤。（2）科尔沁沙地樟子松人工林风沙土质地较粗，分选性较差，偏度值多为正偏度，峰度值多为尖窄，0～10 cm和10～20 cm风沙土分形维数分别为2.18～2.43和1.98～2.17。裸沙地风沙土质地更粗，分选性更好，分形维数更小。（3）科尔沁沙地樟子松人工林风沙土的粒度频率分布曲线均为双峰型。随林龄的增长，10～20 cm风沙土的土壤颗粒细化滞后于0～10 cm。林地悬移组分的含量高于裸沙地，裸沙地跃移组分的分选性高于林地。科尔沁沙地不同樟子松人工林风沙土粒径分布特征存在显著差异，本研究结果可为科 尔沁沙地土地沙漠化防治及生态修复提供理论依据。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-11 Cooperative journals: 《干旱区地理》
Abstract：为揭示毛乌素沙地风沙土粒径分布特征，推测其影响因素，以毛乌素沙地流动、半固定和固定沙丘风沙土为研究对象，利用激光衍射技术分析其粒度组成，并计算粒度参数，解析粒配曲线，研究结果表明：（1）毛乌素沙地风沙土优势粒径组为细砂，其平均体积含量约为29.89%～32.46%，不同类型沙丘无显著差异（P>0.05）；少数粒径组分为粗砂、黏粒和极粗砂，其中流动沙丘与半固定、固定沙丘黏粒与粗砂含量均无显著差异（P>0.05），从半固定到固定沙丘，黏粒含量显著增加（P0.05），峰态显著变宽平（P<0.05），半固定沙丘偏态值与其他2种沙丘相比显著偏负（P<0.05）。（3）流动、半固定与固定沙丘跃移组分的粒径区间分别为44～435 μm、63～500 μm和31～354 μm，风沙运动在半固定沙丘中最为强烈。毛乌素沙地风沙土优势粒径组分含量主要受物源影响，少数粒径组分含量主要受沙丘流动性影响，风沙运动强度随沙丘的固定呈先增大后减小的规律。
Subjects: Computer Science >> Computer Application Technology submitted time 2017-03-10
Abstract：随着互联网发展的日益深入，网络已成为当今社会信息传播的主要媒介之一。网络舆情形成迅速，对社会影响巨大，加强网络舆情的监测和分析，值得引起社会各界的高度重视。天玑舆情监测系统是专门针对网络舆情监测的工作要求和特点而打造的，不仅采用了专业化的搜索引擎技术，还融入了更加智能的数据挖掘技术，建立一个以日为周期的网络舆情监测平台，同时配上以周或者以月为基础的舆情分析报告，从而提供了一个便捷、科学、可操作的舆情工作平台。
Peer Review Status:
Awaiting Review
Hits
Hits
Downloads
Comment