分类： 农、林、牧、渔 >> 土壤学 提交时间： 2024-04-15 合作期刊: 《干旱区科学》
摘要： The unique geomorphological features and farming methods in the Mollisol region of Northeast China increase water catchment flow and aggravate the erosion of ephemeral gully (EG). Vegetation suffers from rain erosion and damage during the growth stage, which brings serious problems to the restoration of grass in the early stage. Therefore, effects of coir geotextile and geocell on EG erosion under four confluence intensities were researched in this study. Results of the simulated water discharge erosion test showed that when the confluence strength was less than 30 L/min, geocell and coir geotextile had a good effect on controlling EG erosion, and sediment yield of geocell and coir geotextile was reduced by 25.95%–37.82% and 73.73%–88.96%, respectively. However, when confluence intensity increased to 40 L/min, protective effect of coir geotextile decreased, and sediment yield rate increased sharply by 189.03%. When confluence intensity increased to 50 L/min, the protective effect of coir geotextile was lost. On the other hand, geocell showed that the greater the flow rate, the better the protective effect. In addition, with the increase in confluence intensity, erosion pattern of coir geotextile developed from sheet erosion to intermittent fall and then to completion of main rill, and the protective effect was gradually weakened. In contrast, the protective effect of EG under geocell was gradually enhanced from the continuous rill to the intermittent rill and finally to the intermittent fall. This study shows that coir geotextile and geocell can prevent EG erosion, and the effect of geocell is better than that of coir geotextile on the surface of EG.
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2024-03-13 合作期刊: 《干旱区科学》
摘要： One of the goals of grazing management in the desert steppe is to improve its ecosystem. However, relatively little is known about soil microbe communities in the desert steppe ecosystem under grazing management. In this study, we investigated the diversity and aboveground biomass of Caragana korshinskii Kom. shrub communities in long-term fencing and grazing areas, combined with an analysis of soil physical-chemical properties and genomics, with the aim of understanding how fence management affects plant-soil-microbial inter-relationships in the desert steppe, China. The results showed that fence management (exclosure) increased plant diversity and aboveground biomass in C. korshinskii shrub area and effectively enhanced soil organic carbon (233.94%), available nitrogen (87.77%), and available phosphorus (53.67%) contents. As well, the Shannon indices of soil bacteria and fungi were greater in the fenced plot. Plant-soil changes profoundly affected the alpha- and beta-diversity of soil bacteria. Fence management also altered the soil microbial community structure, significantly increasing the relative abundances of Acidobacteriota (5.31%–8.99%), Chloroflexi (3.99%–5.58%), and Glomeromycota (1.37%–3.28%). The soil bacterial-fungal co-occurrence networks under fence management had higher complexity and connectivity. Based on functional predictions, fence management significantly increased the relative abundance of bacteria with nitrification and nitrate reduction functions and decreased the relative abundance of bacteria with nitrate and nitrite respiration functions. The relative abundances of ecologically functional fungi with arbuscular mycorrhizal fungi, ectomycorrhizal fungi, and saprotrophs also significantly increased under fence management. In addition, the differential functional groups of bacteria and fungi were closely related to plant-soil changes. The results of this study have significant positive implications for the ecological restoration and reconstruction of dry desert steppe and similar areas.
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2024-03-13 合作期刊: 《干旱区科学》
摘要： In the Loess Plateau of China, land-use pattern is a major factor in controlling underlying biological processes. Additionally, the process of land-use pattern was accompanied by abandoned lands, potentially impacting soil microbe. However, limited researches were conducted to study the impacts of land-use patterns on the diversity and community of soil microorganisms in this area. The study aimed to investigate soil microbial community diversity and composition using high-throughput deoxyribonucleic acid (DNA) sequencing under different land-use patterns (apricot tree land, apple tree land, peach tree land, corn land, and abandoned land). The results showed a substantial difference (P<0.050) in bacterial alpha-diversity and beta-diversity between abandoned land and other land-use patterns, with the exception of Shannon index. While fungal beta-diversity was not considerably impacted by land-use patterns, fungal alpha-diversity indices varied significantly. The relative abundance of Actinobacteriota (34.90%), Proteobacteria (20.65%), and Ascomycota (77.42%) varied in soils with different land-use patterns. Soil pH exerted a dominant impact on the soil bacterial communities' composition, whereas soil available phosphorus was the main factor shaping the soil fungal communities' composition. These findings suggest that variations in land-use pattern had resulted in changes to soil properties, subsequently impacting diversity and structure of microbial community in the Loess Plateau. Given the strong interdependence between soil and its microbiota, it is imperative to reclaim abandoned lands to maintain soil fertility and sustain its function, which will have significant ecological service implications, particularly with regards to soil conservation in ecologically vulnerable areas.
分类： 农、林、牧、渔 >> 农业基础学科 提交时间： 2024-02-21 合作期刊: 《干旱区科学》
摘要： Drip irrigation and flood irrigation are major irrigation methods for maize crops in the Hetao Irrigation District, Inner Mongolia Autonomous Region, China. This research delves into the effects of these irrigation methods on carbon dioxide (CO2) exchange and crop growth in this region. The experimental site was divided into drip and flood irrigation zones. The irrigation schedules of this study aligned with the local commonly used irrigation schedule. We employed a developed chamber system to measure the diurnal CO2 exchange of maize plants during various growth stages under both drip and flood irrigation methods. From May to September in 2020 and 2021, two sets of repeated experiments were conducted. In each experiment, a total of nine measurements of CO2 exchange were performed to obtain carbon exchange data at different growth stages of maize crop. During each CO2 exchange measurement event, CO2 flux data were collected every two hours over a day-long period to capture the diurnal variations in CO2 exchange. During each CO2 exchange measurement event, the biological parameters (aboveground biomass and crop growth rate) of maize and environmental parameters (including air humidity, air temperature, precipitation, soil water content, and photosynthetically active radiation) were measured. The results indicated a V-shaped trend in net ecosystem CO2 exchange in daytime, reducing slowly at night, while the net assimilation rate (net primary productivity) exhibited a contrasting trend. Notably, compared with flood irrigation, drip irrigation demonstrated significantly higher average daily soil CO2 emission and greater average daily CO2 absorption by maize plants. Consequently, within the maize ecosystem, drip irrigation appeared more conducive to absorbing atmospheric CO2. Furthermore, drip irrigation demonstrated a faster crop growth rate and increased aboveground biomass compared with flood irrigation. A strong linear relationship existed between leaf area index and light utilization efficiency, irrespective of the irrigation method. Notably, drip irrigation displayed superior light use efficiency compared with flood irrigation. The final yield results corroborated these findings, indicating that drip irrigation yielded higher harvest index and overall yield than flood irrigation. The results of this study provide a basis for the selection of optimal irrigation methods commonly used in the Hetao Irrigation District. This research also serves as a reference for future irrigation studies that consider measurements of both carbon emissions and yield simultaneously.
分类： 农、林、牧、渔 >> 林学 提交时间： 2024-02-21 合作期刊: 《干旱区科学》
摘要： Tree plantation and forest restoration are the major strategies for enhancing terrestrial carbon sequestration and mitigating climate change. The Grain for Green Project in China has positively impacted global carbon sequestration and the trend towards fragmentation of plantation forests. Limited studies have been conducted on changes in plantation biomass and stand structure caused by fragmentation, and the effect of fragmentation on the carbon storage of plantation forests remains unclear. This study evaluated the differences between carbon storage and stand structure in black locust forests in fragmented and continuous landscape in the Ansai District, China and discussed the effects of ecological significance of four landscape indices on carbon storage and tree density. We used structural equation modelling to explore the direct and indirect effects of fragmentation, edge, abiotic factors, and stand structure on above-ground carbon storage. Diameter at breast height (DBH) in fragmented forests was 53.3% thicker, tree density was 40.9% lower, and carbon storage was 49.8% higher than those in continuous forests; for all given DBH>10 cm, the trees in fragmented forests were shorter than those in continuous forests. The patch area had a negative impact on carbon storage, i.e., the higher the degree of fragmentation, the lower the density of the tree; and fragmentation and distance to edge (DTE) directly increased canopy coverage. However, canopy coverage directly decreased carbon storage, and fragmentation directly increased carbon storage and tree density. In non-commercial forests, fragmentation reduces the carbon storage potential of plantation, and the influence of patch area, edge, and patchy connection on plantation should be considered when follow-up trees are planted and for the plantation management. Thus, expanding the area of plantation patches, repairing the edges of complex-shaped patches, enhancing the connectivity of similar patches, and applying nutrients to plantation forests at regular intervals are recommended in fragmented areas of the Loess Plateau.
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2024-01-12 合作期刊: 《干旱区科学》
摘要： Vegetation restoration through artificial plantation is an effective method to combat desertification, especially in arid and semi-arid areas. This study aimed to explore the ecological effect of the plantation of Sabina vulgaris on soil physical and chemical properties on the southeastern fringe of the Mu Us Sandy Land, China. We collected soil samples from five depth layers (020, 2040, 4060, 6080, and 80100 cm) in the S. vulgaris plantation plots across four plantation ages (4, 7, 10, and 16 years) in November 2019, and assessed soil physical (soil bulk density, soil porosity, and soil particle size) and chemical (soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), available potassium (AK), cation-exchange capacity (CEC), salinity, pH, and C/N ratio) properties. The results indicated that the soil predominantly consisted of sand particles (94.27%99.67%), with the remainder being silt and clay. As plantation age increased, silt and very fine sand contents progressively rose. After 16 years of planting, there was a marked reduction in the mean soil particle size. The initial soil fertility was low and declined from 4 to 10 years of planting before witnessing an improvement. Significant positive correlations were observed for the clay, silt, and very fine sand (mean diameter of 0.0000.100 mm) with SOC, AK, and pH. In contrast, fine sand and medium sand (mean diameter of 0.1000.500 mm) showed significant negative correlations with these indicators. Our findings ascertain that the plantation of S. vulgaris requires 10 years to effectively act as a windbreak and contribute to sand fixation, and needs 16 years to improve soil physical and chemical properties. Importantly, these improvements were found to be highly beneficial for vegetation restoration in arid and semi-arid areas. This research can offer valuable insights for the protection and restoration of the vegetation ecosystem in the sandy lands in China.
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2024-01-12 合作期刊: 《干旱区科学》
摘要： Proposed agroforestry options should begin with the species that farmers are most familiar with, which would be the native multipurpose trees that have evolved under smallholder farms and socioeconomic conditions. The African birch (Anogeissus leiocarpa (DC.) Guill. Perr.) and pink jacaranda (Stereospermum kunthianum Cham.) trees are the dominant species in the agroforestry parkland system in the drylands of Tigray, Ethiopia. Smallholder farmers highly value these trees for their multifunctional uses including timber, firewood, charcoal, medicine, etc. These trees also could improve soil fertility. However, the amount of soil physical and chemical properties enhanced by the two species must be determined to maintain the sustainable conservation of the species in the parklands and to scale up to similar agro- ecological systems. Hence, we selected twelve isolated trees, six from each species that had similar dendrometric characteristics and were growing in similar environmental conditions. We divided the canopy cover of each tree into three radial distances: mid-canopy, canopy edge, and canopy gap (control). At each distance, we took soil samples from three different depths. We collected 216 soil samples (half disturbed and the other half undisturbed) from each canopy position and soil depth. Bulk density (BD), soil moisture content (SMC), soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP), available potassium (AK), pH, electrical conductivity (EC), and cation exchange capacity (CEC) were analysed. Results revealed that soil physical and chemical properties significantly improved except for soil texture and EC under both species, CEC under A. leiocarpus, and soil pH under S. kunthianum, all the studied soils were improved under both species canopy as compared with canopy gap. SMC, TN, AP, and AK under canopy of these trees were respectively 24.1%, 11.1%, 55.0%, and 9.3% higher than those soils under control. The two parkland agroforestry species significantly enhanced soil fertility near the canopy of topsoil through improving soil physical and chemical properties. These two species were recommended in the drylands with similar agro-ecological systems.
分类： 农、林、牧、渔 >> 农业史 提交时间： 2023-12-29
摘要： 北魏贾思勰撰著的《齐民要术》是中国传统农学经典中的经典，也是研究中国古代史的重要史料。该书共十卷，除第十卷标题为五谷、果蓏、菜茹非中国物产者外，言下之意，前九卷所载之内容，当属北魏统治下的所谓中国之物产。因而，《齐民要术》也被认为是反映中国古代黄河流域农业的农学著作，即北方农书。但细检书中内容，却发现书中包含有许多非典型性北方因素，如，稻、鱼、竹、橘、莼、莲、芡、芰、菰、菘、姜、杬、越瓜、山石榴（杜鹃花）、水牛等。这些因素除了当时北方环境提供了某种可能的存在外，从地名、稻作技术和鱼类分布等方面都显示出某种南方因素的介入与存在。本文从物产和技术入手，揭示其中的南方农业因素，探讨其进入北方的途径，包括人员往来和文本传播，藉以展示前此相关研究未曾注意的一面，即中国南、北方农业文化交流与技术传播。
分类： 农、林、牧、渔 >> 农业基础学科 提交时间： 2023-11-13 合作期刊: 《干旱区科学》
摘要： Climate warming has led to the expansion of arable land at high altitudes, but it has also increased the demand for water use efficiency (WUE). To address this issue, the development of water-saving irrigation technology has become crucial in improving water productivity and economic returns. This study aimed to assess the impacts of three irrigation methods on water productivity and economic returns in wolfberry (Lycium barbarum L.) cultivation on the Tibetan Plateau, China during a two-year field trial. Results showed that subsurface irrigation with ceramic emitters (SICE) outperformed surface drip irrigation (DI) and subsurface drip irrigation (SDI) in terms of wolfberry yield. Over the two-year period, the average yield with SICE increased by 8.0% and 2.3% compared with DI and SDI, respectively. This improvement can be attributed to the stable soil moisture and higher temperature accumulation achieved with SICE. Furthermore, SICE exhibited higher WUE, with 14.6% and 4.5% increases compared with DI and SDI, respectively. In addition to the agronomic benefits, SICE also proved advantageous in terms of economic returns. Total average annual input costs of SICE were lower than the other two methods starting from the 8th year. Moreover, the benefit-cost ratio of SICE surpassed the other methods in the 4th year and continued to widen the gap with subsequent year. These findings highlight SICE as an economically viable water-saving irrigation strategy for wolfberry cultivation on the Tibetan Plateau. Thus, this research not only provides an effective water-saving irrigation strategy for wolfberry cultivation but also offers insights into addressing irrigation-related energy challenges in other crop production systems.
分类： 农、林、牧、渔 >> 农业基础学科 提交时间： 2023-10-17 合作期刊: 《干旱区科学》
摘要： The unreasonable nitrogen (N) supply and low productivity are the main factors restricting the sustainable development of processing tomatoes. In addition, the mechanism by which the N application strategy affects root growth and nitrate distributions in processing tomatoes remains unclear. In this study, we applied four N application levels to a field (including 0 (N0), 200 (N200), 300 (N300), and 400 (N400) kg/hm2) based on the critical N absorption ratio at each growth stage (planting stage to flowering stage: 22%; fruit setting stage: 24%; red ripening stage: 45%; and maturity stage: 9%). The results indicated that N300 treatment significantly improved the aboveground dry matter (DM), yield, N uptake, and nitrogen use efficiency (NUE), while N400 treatment increased nitrate nitrogen (NO3-N) residue in the 2060 cm soil layer. Temporal variations of total root dry weight (TRDW) and total root length (TRL) showed a single-peak curve. Overall, N300 treatment improved the secondary root parameter of TRDW, while N400 treatment improved the secondary root parameter of TRL. The grey correlation coefficients indicated that root dry weight density (RDWD) in the surface soil (020 cm) had the strongest relationship with yield, whereas root length density (RLD) in the middle soil (2040 cm) had a strong relationship with yield. The path model indicated that N uptake is a crucial factor affecting aboveground DM, TRDW, and yield. The above results indicate that N application levels based on critical N absorption improve the production of processing tomatoes by regulating N uptake and root distribution. Furthermore, the results of this study provide a theoretical basis for precise N management.
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2023-10-17 合作期刊: 《干旱区科学》
摘要： Leguminosae are an important part of terrestrial ecosystems and play a key role in promoting soil nutrient cycling and improving soil properties. However, plant composition and species diversity change rapidly during the process of succession, the effect of leguminosae on soil physical-chemical and biological properties is still unclear. This study investigated the changes in the composition of plant community, vegetation characteristics, soil physical-chemical properties, and soil biological properties on five former farmlands in China, which had been abandoned for 0, 5, 10, 18, and 30 a. Results showed that, with successional time, plant community developed from annual plants to perennial plants, the importance of Leguminosae and Asteraceae significantly increased and decreased, respectively, and the importance of grass increased and then decreased, having a maximum value after 5 a of abandonment. Plant diversity indices increased with successional time, and vegetation coverage and above- and below-ground biomass increased significantly with successional time after 5 a of abandonment. Compared with farmland, 30 a of abandonment significantly increased soil nutrient content, but total and available phosphorus decreased with successional time. Changes in plant community composition and vegetation characteristics not only change soil properties and improve soil physical-chemical properties, but also regulate soil biological activity, thus affecting soil nutrient cycling. Among these, Leguminosae have the greatest influence on soil properties, and their importance values and community composition are significantly correlated with soil properties. Therefore, this research provides more scientific guidance for selecting plant species to stabilize soil ecosystem of farmland to grassland in the Loess Plateau, China.
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2023-10-17 合作期刊: 《干旱区科学》
摘要： Restoration of mining soils is important to the vegetation and environment. This study aimed to explore the variations in soil nutrient contents, microbial abundance, and biomass under different gradients of substrate amendments in mining soils to select effective measures. Soil samples were collected from the Bayan Obo mining region in Inner Mongolia Autonomous Region, China. Contents of soil organic matter (SOM), available nitrogen (AN), available phosphorus (AP), available potassium (AK), microbial biomass carbon/microbial biomass nitrogen (MBC/MBN) ratio, biomass, and bacteria, fungi, and actinomycetes abundance were assessed in Agropyron cristatum L. Gaertn., Elymus dahuricus Turcz., and Medicago sativa L. soils with artificial zeolite (AZ) and microbial fertilizer (MF) applied at T0 (0 g/kg), T1 (5 g/kg), T2 (10 g/kg), and T3 (20 g/kg). Redundancy analysis (RDA) and technique for order preference by similarity to ideal solution (TOPSIS) were used to identify the main factors controlling the variation of biomass. Results showed that chemical indices and microbial content of restored soils were far greater than those of control. The application of AZ significantly increases SOM, AN, and AP by 20.27%, 23.61%, and 40.43%, respectively. AZ significantly increased bacteria, fungi, and actinomycetes abundance by 0.63, 3.12, and 1.93 times of control, respectively. RDA indicated that AN, MBC/MBN ratio, and SOM were dominant predictors for biomass across samples with AZ application, explaining 87.6% of the biomass variance. SOM, MBC/MBN ratio, and AK were dominant predictors with MF application, explaining 82.9% of the biomass variance. TOPSIS indicated that T2 was the best dosage and the three plant species could all be used to repair mining soils. AZ and MF application at T2 concentration in the mining soils with M. sativa was found to be the most appropriate measure.
分类： 农、林、牧、渔 >> 农、林、牧、渔业科学其他学科 提交时间： 2023-09-05 合作期刊: 《农业图书情报学报》
摘要： 目的/ 意义 不同合作者在科研合作中扮演不同角色，承担相应职责。区分科研合作对象中的不同角色，对于科研人才评价和人力资源配置具有重要意义。本文基于 H 指数的测算方式，使用合作次数来识别科学家合作关系中的核心合作者。 方法/ 过程 以中国与G7 国家计算机领域高产科学家为研究对象。首先，识别出核心合作者并分析其规模与占比。其次，基于 H 指数拟合公式提出核心合作者人数的估算公式。最后，利用该式比较理论值与实际值的差异。 结果 / 结论 研究发现，在核心合作者的规模与占比上，各国核心合作者人数普遍为 3 耀7 人，且比例均不超过 10%。核心合作者人数可使用发文量与 篇均合作者人数的幂次方乘积来估算，美国、德国和英国的核心合作者占比更低，人才的流动和交流较为频繁，而意大利、日本和中国的核心合作者人数占比偏高，表明人才流动性不足，科研合作相对固化。
分类： 农、林、牧、渔 >> 畜牧、兽医科学 分类： 医学、药学 >> 军事医学与特种医学 提交时间： 2023-08-28
摘要： 本文总结1例痛风性关节炎急性发作患者行金黄散贴敷疗法的护理体会。基于中医辨证，通过采用金黄散外用贴敷治疗，结合健康教育、饮食指导等综合护理干预，使患者达到疼痛缓解的效果。
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2023-08-26 合作期刊: 《干旱区研究》
摘要： 农田防护林作为提高生态环境效益的有效农业管理方式，对改善土壤理化性质、改善生态环境，提高作物产量具有重要意义。在河套灌区选择三种典型农田防护林（4行林带、5行林带和8行林带）测量了20192021年生长季农田内距防护林0.3 H、0.7 H、1 H、2 H、3 H和4 H处0~100 cm的土壤性质和防护林与农田的植被属性，测算了土壤水分储量（SMS）和土壤养分储量[碳储量(SCS)、氮储量(SNS)和磷储量(SPS)］。结果表明：（1）不同防护林系统水平方向上的土壤容重和土壤黏粒含量差异显著，在垂直方向上土壤属性均有显著差异。（2）防护林具有较好的保水性和养分供应功能，其中4行林带的土壤水分储量和养分储量高于其他林带，分别为SMS 237.44 mm、SCS 544.93 gm-2、SNS 953.72 gm-2和SPS 859.04 gm-2。（3）4行林带的整体长势比较好，其平均树高为30.06 m，胸径为0.41 m，且4行防护林的作物产量最高，为15.75 thm-2。（4）冗余分析结果显示，不同防护林系统中，环境因子与生态系统功能之间存在密切关系，土壤特性与土壤水分和养分储量关系密切，另外，植被属性与SNS和SPS基本呈负相关。综上所述，4行林带的水分养分供给能力最强，本研究结果可为生态脆弱地区的防护林建设和生态修复提供有效的理论依据。
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2023-08-26 合作期刊: 《干旱区研究》
摘要： 快速监测区域土壤盐渍化信息，对于盐渍化治理与生态环境保护具有重要意义。本文以Sentinel-2A和Landsat8 OLI遥感影像为数据源，以银川平原为研究区，利用谷歌地球引擎（Google Earth Engine，GEE）平台，基于随机森林算法，通过建立光谱指数特征与地面实测土壤含盐量之间的关系，进行土壤含盐量估算。结果表明：GEE能够为土壤含盐量预测提供可靠的数据支撑；以Sentinel-2A为数据源建立的随机森林模型具有更好的预测精度（R2=0.789，RMSE=1.487），优于Landsat8 OLI，可用于土壤含盐量高分辨率遥感估算，能够为大尺度土壤含盐量监测工作提供理论支撑。
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2023-08-26 合作期刊: 《干旱区研究》
摘要： 塔里木河生态输水使流域两岸洪水漫溢强度增加，进而对河岸胡杨林生态系统碳循环产生了重要影响。以塔里木河中游周期性洪水漫溢区胡杨林为研究对象，测定并分析河岸胡杨林洪水漫溢过程中漫溢前（W1）、漫溢第4 d（W2）、漫溢第17 d（W3）和退水后（W4）4个不同阶段1 m土体有机碳及活性组分含量的变化特征。结果表明：（1）SOC（土壤有机碳）含量在漫溢前均高于漫溢后；洪水漫溢对0~20 cm土层SOC含量的影响较20~100 cm土层显著；在同一阶段内，随着土层的深入，SOC含量呈降低趋势。（2）0~10 cm及40~100 cm土层的土壤DOC（可溶性有机碳）、MBC（微生物生物量碳）含量在漫溢第4 d较漫溢前均显著升高，但随着漫溢时间的延长，其含量逐渐降低，且各阶段间差异显著(P<0.05)；同一土层随漫溢时间的延长DOC/SOC、MBC/SOC差异显著(P<0.05)。（3）漫溢前0~10cm土层EOC（易氧化有机碳）含量高于漫溢后，其他土层EOC含量则表现为漫溢期高于漫溢前及退水后；0~10 cm、20~60 cm土层EOC/SOC在不同漫溢阶段间差异显著(P<0.05)。（4）漫溢前至漫溢第17 d SOC与DOC含量呈极显著正相关（r＞0.69，n=15），退水后EOC和DOC呈显著正相关（r=0.54，n=15），漫溢前SOC和DOC含量与漫溢后各阶段含量之间相关性显著。综上所述，塔里木河中游洪水漫溢过程对河岸胡杨林SOC及活性组分分布产生了显著影响，并且各组分的敏感土层不同，SOC以0~20 cm土层影响最为显著，DOC、MBC以0~10 cm及40~100 cm土层影响最为显著，EOC则为20~60 cm土层影响最为显著，其变化规律具有森林和湿地的双重特征。
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2023-08-25 合作期刊: 《干旱区研究》
摘要： 水分利用效率（WUE）是农田生态系统碳水循环的重要指标，对指导农业灌溉和提高水分生产力有重要意义。宁夏灌区是我国地处干旱气候带的大型灌区，其中，玉米种植面积最大。在涡度通量观测农田生态系统实际蒸散发（ET）的基础上，利用氢氧稳定同位素法将蒸散发分割为土壤蒸发（evaporation，E）、植物蒸腾（transpiration，T），并通过光能利用模型估算宁夏引黄灌区典型玉米农田生态系统的总初级生产力（GPP），计算群体水分利用效率WUET=GPP/T、生态系统水分利用效率WUEET=GPP/ET 以及固有水分利用效率（Intrinsic Water Use Efficiency）IWUEVPD=（GPPVPD）/ET三种水分利用效率，进而从函数响应关系、相关性以及敏感性三个方面分析不同水分利用效率与气温、饱和水汽压差（VPD）、CO2浓度、光合有效辐射以及土壤含水量等环境因子之间的关系。结果表明：宁夏引黄灌区玉米农田生态系统生长季的实际蒸散发变化呈单驼峰型，作物蒸腾与实际蒸散发的变化趋势相一致。WUET在生育期内呈W型变化，WUEET与IWUEVPD在生育期内呈单峰型变化，三种WUE的峰值出现在抽雄期，分别达到5.90 kg Cm-3H2O、5.02 kg Cm-3H2O和32.90 kg ChPam-3H2O，灌浆后期三种水分利用效率开始降低，玉米成熟晚期由于蒸腾微弱所以WUET略有增加。WUET、WUEET和IWUEVPD与土壤含水量显著正相关，相关度和敏感性最强；VPD与三种WUE显著负相关，相关度和敏感性最强次之；气温、光合有效辐射以及CO2浓度与三种WUE的负相关性但不是敏感因素。因此，在宁夏引黄灌区土壤水分和VPD是影响玉米农田生态系统WUE的关键因素。
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2023-08-25 合作期刊: 《干旱区研究》
摘要： 为探究沙漠化逆转过程中林地土壤呼吸速率和通量变化趋势及其主要影响因子，本文选择毛乌素沙地林龄为9 a、18 a和30 a杨柴人工灌木林和未造林流动沙地（CK），用Li-8100A土壤碳通量监测系统对土壤呼吸速率进行定位观测，并对主要环境影响因子进行了测定。结果表明：（1）土壤呼吸速率和通量均在植物生长季510月呈现出先升高后降低的单峰曲线变化规律，最高值出现在7月。（2）土壤呼吸速率和通量随杨柴林龄增长呈持续增加趋势，而呼吸速率温度敏感性（Q10）则呈持续下降趋势。生长季510月杨柴林各样地土壤呼吸平均速率大小为：30 a(2.16 molm-2s-1)＞18 a(1.98 molm-2s-1)＞9 a(1.41 molm-2s-1)＞CK(0.24 molm-2s-1)；土壤呼吸碳通量值大小顺序为：30 a(365.74 g Cm-2)＞18 a(313.63 g Cm-2)＞9 a(218.66 g Cm-2)＞CK(40.08 g Cm-2)。（3）CK、9 a和18 a样地土壤呼吸速率季节性变化主要受土壤温度和水分的耦合作用(P＜0.01)，而30 a样地的主控因子为土壤温度(P＜0.01)。（4）土壤呼吸碳通量与植被生物量、土壤有机碳和全氮含量均呈显著正相关关系(P＜0.05)。
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2023-08-25 合作期刊: 《干旱区研究》
摘要： 降雨是湿地水资源补给量和土壤呼吸的重要扰动因子，全球气候变化导致的未来极端降雨变率增大对湿地生态系统有着重要影响。为探究极端降雨频率下青藏高原湿草甸土壤有机碳（SOC）、全氮（TN）、全磷（TP）含量及化学计量比的变化特征，本文以青藏高原东北边缘碌曲县尕海-则岔自然保护区境内的湿草甸土壤为研究对象，设置空白对照（CK：0 mm）、每周浇灌一次（DF1：25 mm19次）、每两周浇灌一次（DF2：25 mm9次）、每三周浇灌一次（DF3：25 mm6次）和每四周浇灌一次（DF4：25 mm4次）5种处理，分析极端降雨频率下0~40 cm土层土壤SOC、TN和TP化学计量特征的变化规律。结果表明：在不同降雨频率下，土壤SOC含量随降雨频率增加而增加，TN和TP含量则与之相反。在土壤垂直剖面上，SOC和TN含量均随土层深度增加而降低，TP含量随土层深度增加无显著变化；C:P和N:P均随土层加深有所降低，而C:N随土层加深无显著变化；C:N、C:P和N:P在不同降雨频率间差异不显著；此外，随着时间的推进，土壤SOC含量在生长季不同月份呈现先增后减的变化趋势，TN含量则呈现先减后增的变化趋势，而TP含量呈M型变化趋势。因此，随着全球降雨格局变化程度持续增加，较高的降雨频率会加剧高寒湿草甸浅层土壤氮磷含量的流失，造成高寒湿草甸水环境富营养化的危害加剧。
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