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1. chinaXiv:201906.00046 [pdf]

Multi-scale spatial relationships between soil total nitrogen and influencing factors in a basin landscape based on multivariate empirical mode decomposition

ZHU Hongfen
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

The relationships between soil total nitrogen (STN) and influencing factors are scale-dependent. The objective of this study was to identify the multi-scale spatial relationships of STN with selected environmental factors (elevation, slope and topographic wetness index), intrinsic soil factors (soil bulk density, sand content, silt content, and clay content) and combined environmental factors (including the first two principal components (PC1 and PC2) of the Vis-NIR soil spectra) along three sampling transects located at the upstream, midstream and downstream of Taiyuan Basin on the Chinese Loess Plateau. We separated the multivariate data series of STN and influencing factors at each transect into six intrinsic mode functions (IMFs) and one residue by multivariate empirical mode decomposition (MEMD). Meanwhile, we obtained the predicted equations of STN based on MEMD by stepwise multiple linear regression (SMLR). The results indicated that the dominant scales of explained variance in STN were at scale 995 m for transect 1, at scales 956 and 8852 m for transect 2, and at scales 972, 5716 and 12,317 m for transect 3. Multi-scale correlation coefficients between STN and influencing factors were less significant in transect 3 than in transects 1 and 2. The goodness of fit root mean square error (RMSE), normalized root mean square error (NRMSE), and coefficient of determination (R2) indicated that the prediction of STN at the sampling scale by summing all of the predicted IMFs and residue was more accurate than that by SMLR directly. Therefore, the multi-scale method of MEMD has a good potential in characterizing the multi-scale spatial relationships between STN and influencing factors at the basin landscape scale.

submitted time 2019-06-20 From cooperative journals:《Journal of Arid Land》 Hits1165Downloads188 Comment 0

2. chinaXiv:201903.00234 [pdf]

Effects of spring fire and slope on the aboveground biomass, and organic C and N dynamics in a semi-arid grassland of northern China

ZHAO Xiang; HU Shuya
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

The aboveground primary production is a major source of carbon (C) and nitrogen (N) pool and plays an important role in regulating the response of ecosystem and nutrient cycling to natural and anthropogenic disturbances. To explore the mechanisms underlying the effect of spring fire and topography on the aboveground biomass (AGB) and the soil C and N pool, we conducted a field experiment between April 2014 and August 2016 in a semi-arid grassland of northern China to examine the effects of slope and spring fire, and their potential interactions on the AGB and organic C and total N contents in different plant functional groups (C3 grasses, C4 grasses, forbs, Artemisia frigida plants, total grasses and total plants). The dynamics of AGB and the contents of organic C and N in the plants were examined in the burned and unburned plots on different slope positions (upper and lower). There were differences in the total AGB of all plants between the two slope positions. The AGB of grasses was higher on the lower slope than on the upper slope in July. On the lower slope, spring fire marginally or significantly increased the AGB of C3 grasses, forbs, total grasses and total plants in June and August, but decreased the AGB of C4 grasses and A. frigida plants from June to August. On the upper slope, however, spring fire significantly increased the AGB of forbs in June, the AGB of C3 grasses and total grasses in July, and the AGB of forbs and C4 grasses in August. Spring fire exhibited no significant effect on the total AGB of all plants on the lower and upper slopes in 2014 and 2015. In 2016, the total AGB in the burned plots showed a decreasing trend after fire burning compared with the unburned plots. The different plant functional groups had different responses to slope positions in terms of organic C and N contents in the plants. The lower and upper slopes differed with respect to the organic C and N contents of C3 grasses, C4 grasses, total grasses, forbs, A. frigida plants and total plants in different growing months. Slope position and spring fire significantly interacted to affect the AGB and organic C and N contents of C4 grasses and A. frigida plants. We observed the AGB and organic C and N contents in the plants in a temporal synchronized pattern. Spring fire affected the functional AGB on different slope positions, likely by altering the organic C and N contents and, therefore, it is an important process for C and N cycling in the semi-arid natural grasslands. The findings of this study would facilitate the simulation of ecosystem C and N cycling in the semi-arid grasslands in northern China.

submitted time 2019-03-28 From cooperative journals:《Journal of Arid Land》 Hits1305Downloads248 Comment 0

3. chinaXiv:201903.00236 [pdf]

Distribution of soil aggregates and organic carbon in deep soil under long-term conservation tillage with residual retention in dryland

WANG Bisheng; GAO Lili; WEI Xueqin
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

To ascertain the effects of long-term conservation tillage and residue retention on soil organic carbon (SOC) content and aggregate distribution in a deep soil (>20-cm depth) in a dryland environment, this paper analyzed the SOC and aggregate distribution in soil, and the aggregate-associated organic carbon (OC) and SOC physical fractions. Conservation tillage (reduced tillage with residue incorporated (RT) and no-tillage with residue mulch (NT)) significantly increased SOC sequestration and soil aggregation in deep soil compared with conventional tillage with residue removal (CT). Compared with CT, RT significantly increased the proportion of small macroaggregates by 23%–81% in the 10–80 cm layer, and the OC content in small macroaggregates by 1%–58% in the 0–80 cm layer. RT significantly increased (by 24%–90%) the OC content in mineral-SOC within small macroaggregates in the 0–60 cm layer, while there was a 23%–80% increase in the 0–40 cm layer with NT. These results indicated that: (1) conservation tillage treatments are beneficial for soil aggregation and SOC sequestration in a deep soil in a dryland environment; and (2) the SOC in mineral-associated OC plays important roles in soil aggregation and SOC sequestration. In conclusion, RT with NT is recommended as an agricultural management tool in dryland soils because of its role in improving soil aggregation and SOC sequestration.

submitted time 2019-03-28 From cooperative journals:《Journal of Arid Land》 Hits1644Downloads270 Comment 0

4. chinaXiv:201811.00103 [pdf]

Changes in soil microbial community response to precipitation events in a semi-arid steppe of the Xilin River Basin, China

ZHANG Hui; LIU Wenjun; KANG Xiaoming; CUI Xiaoyong; WANG Yanfen; ZHAO Haitao; QIAN Xiaoqing; HAO Yanbin
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

In the context of climate change, precipitation is predicted to become more intense at the global scale. Such change may alter soil microbial communities and the microbially mediated carbon and nitrogen dynamics. In this study, we experimentally repackaged precipitation patterns during the growing season (from June to September) of 2012 in a semi-arid temperate steppe of the Xilin River Basin in Inner Mongolia of China, based on the 60-year growing season precipitation data. Specifically, we manipulated a total amount of 240 mm precipitation to experimental plots by taking the following treatments: (1) P6 (6 extreme precipitation events, near the 1st percentile); (2) P10 (10 extreme precipitation events, near the 5th percentile); (3) P16 (16 moderate precipitation events, near the 50th percentile); and (4) P24 (24 events, 60-year average precipitation, near the 50th percentile). At the end of the growing season, we analyzed soil microbial community structure and biomass, bacterial abundance, fungal abundance and bacterial composition, by using phospholipid fatty acid (PLFA), real-time quantitative polymerase chain reaction (RT-qPCR) and 16S rRNA gene clone library methods. The extreme precipitation events did not change soil microbial community structure (represented by the ratio of PLFA concentration in fungi to PLFA concentration in bacteria, and the ratio of PLFA concentration in gram-positive bacterial biomass to PLFA concentration in gram-negative bacterial biomass). However, the extreme precipitation events significantly increased soil microbial activity (represented by soil microbial biomass nitrogen and soil bacterial 16S rRNA gene copy numbers). Soil fungal community showed no significant response to precipitation events. According to the redundancy analysis, both soil microbial biomass nitrogen and soil ammonium nitrogen (NH4-N) were found to be significant in shaping soil microbial community. Acidobacteria, Actinobacteria and Proteobacteria were the dominant phyla in soil bacterial composition, and responded differently to the extreme precipitation events. Based on the results, we concluded that the extreme precipitation events altered the overall soil microbial activity, but did not impact how the processes would occur, since soil microbial community structure remained unchanged.

submitted time 2018-11-23 From cooperative journals:《Journal of Arid Land》 Hits1993Downloads398 Comment 0

5. chinaXiv:201807.00075 [pdf]

基于SCI文献计量分析的土壤电动修复研究.docx.docx

袁立竹; 盛宇平; 盛春蕾; 郭书海
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

土壤电动修复是一种新兴的土壤修复技术。本文以1972-2017土壤电动修复SCI文献为分析对象,通过定量统计和文本挖掘对过去45年土壤电动修复发展历程和研究态势进行了描述。根据对关键词的整理与分析,发现土壤电动修复研究主要围绕电动修复机理、联合修复技术和场地应用等3个方面,重点修复对象主要是重金属、有机污染物、盐和其他离子以及复合污染物等。开发便捷高效的电动修复场地应用技术将是今后的研究重点之一;电动修复技术与其他修复技术的有机结合,联合修复已成为电动修复研究的热点。

submitted time 2018-07-26 Hits1384Downloads633 Comment 2

6. chinaXiv:201808.00151 [pdf]

宁夏枸杞(LyciumbarbarumL.)花器官形态多样性与品系间识别研究

张益芝; 戴国礼; 秦垦; 马海军
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Plant Protection

本研究以宁夏枸杞( L y c i u m b a r b a r u mL.)种内 42 个品系为实验材料,在对其花器官的 16 项性状的形态学指标进行赋值,测量的基础上,利用组间单因素方差分析、主成分分析和聚类分析法对其形态学差异的多态性进行了研究。研究结果表明:同一品系宁夏枸杞花器官形态学指标在不同时间(具体观测时间为 2017 年 7 月、8 月、9 月)p<0.05,差异不显著;同时,主成分分析显示花瓣外缘色泽、花瓣正-背面脉络、花瓣形状、花瓣背部色泽、花喉色泽、雌雄蕊位置 6 个花部形态指标的累积贡献率达到 84.791%,为宁夏枸杞不同品系花器官差异的主成分;聚类分析以欧式距离 7.5 为阈值,将参加试的 42 个品系分成 6类。通过本项研究明确了,同一品系的宁夏枸杞花器官形态在不同时间表现出一定的稳定性,作为区分宁夏枸杞种内不同品系的鉴别指标之一;同时,筛选出了反映宁夏枸杞花器官形态差异的 6 个主成分并将 42份宁夏枸杞分为六类,初步建立了宁夏枸杞种内品系间的形态学鉴别方法,可为宁夏枸杞的形态学研究及品系鉴定等工作提供依据。

submitted time 2018-07-18 From cooperative journals:《广西植物》 Hits2539Downloads483 Comment 0

7. chinaXiv:201808.00150 [pdf]

基于 OTCs 模拟增温方式探讨气候变暖对青藏高原草地生态系统的影响

张相锋; 彭阿辉; 宋凤仙; 陈冬勤
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Plant Protection

开顶式生长室(OTCs)增温实验是研究全球气候变化与陆地生态系统关系的主要方法之一,已广泛 应用于青藏高原地区。该文通过对近些年国内外研究文献的回顾,分别从植物物候、群落结构、生物量和 土壤方面综合分析青藏高原草地生态系统对 OTCs 模拟增温实验的响应。研究发现:增温使群落返青期提 前、枯黄期延迟,生长季延长;有利于禾本科植物的生长;高寒草甸地下生物量分配格局向深层转移;高寒草地生态系统对模拟增温的响应存在不确定性,受到地域、群落类型和实验时间的影响;在增温条件下,降雨和冻土融化引起的土壤水分变化通过调控生态系统的物候、生产力、土壤等途径控制着生态系统对气 候变暖的响应。在并在此基础上,提出了将来应着重研究的几个方面。

submitted time 2018-07-18 From cooperative journals:《广西植物》 Hits2937Downloads480 Comment 0

8. chinaXiv:201808.00149 [pdf]

Cu 胁迫下基质中凹凸棒石粘土对当归幼苗的保护作用

张牡丹; 赛闹汪青; 冉瑞兰; 达梦婷; 贾凌云; 孙坤; 冯汉青
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Plant Protection

在含有不同比例凹凸棒石粘土的混合基质中(凹凸棒石粘土:基质的体积比分别为 0/1、1/100、1/70、1/50、1/20)培育当归幼苗,以研究 Cu 胁迫对当归幼苗的生理学影响及凹凸棒石粘土对 Cu 胁迫下当归幼苗的保护作用。结果发现:(1)基质中不存在凹凸石棒石粘土时,随着 CuCl2处理浓度的上升,当归幼苗叶片的实际光化学效率[Y(II)]、PSII 电子传递速率(ETR)、光化学淬灭(qP)和叶绿素含量都逐渐降低;而叶片的非光化学猝灭(qN)、可溶性蛋白含量、抗氧化酶活性(SOD、POD、CAT、APX)、过氧化氢含量以及根和叶片中的 Cu 含量均显著性增加,表明 Cu 胁迫降低了当归幼苗的光化学效率、叶绿素的合成、增加了组织中 Cu 含量和氧化压力;(2)CuCl2胁迫下,当基质中存在不同比例的凹凸棒石粘土时,Cu 胁迫所导致的叶片 Y(II)、ETR、qP 及叶绿素含量的降低以及叶片 qN、可溶性蛋白含量、抗氧化酶活性、过氧化氢含量、根和叶片的 Cu 含量的升高均有所缓解,这是因为凹凸棒石粘土通过吸附或固定基质中游离的以及可交换的 Cu 离子,减少了当归幼苗对有效 Cu 离子的吸收,从而缓解了 Cu 离子对植物造成的生理学压力,且这种缓解作用依次为:1/70>1/50>1/20≧ 1/100>0/1,这是由于基质中存在过多的凹凸棒石粘土时,其在吸收基质中 Cu 离子的同时也会影响基质的通气性、透水性和酸碱度等。上述结果表明:凹凸棒石粘土在基质中的适当加入能够缓解 Cu 胁迫对当归幼苗造成的的生理学压力。该实验结果为当归在无土化栽培中重金属污染的减少提供一定的借鉴和参考。

submitted time 2018-07-18 From cooperative journals:《广西植物》 Hits3097Downloads506 Comment 0

9. chinaXiv:201808.00148 [pdf]

西藏虎头兰高效植株再生体系的研究

袁芳; 宋凯杰; 蔡熙彤; 杨泽东; 王 兵; 兰小中
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Plant Protection

西藏虎头兰(Cymbidium tracyanum)为兰科兰属多年生草本植物,是一种极具观赏价值的野生花卉,目前关于西藏 虎头兰组培快繁的研究报道甚少。该研究以野生西藏虎头兰种子为外植体,通过分析不同基本培养基和植物激素配比对原球茎诱导、增殖和分化的影响,以及光照时间和培养温度对试管苗生长的影响,筛选出适宜西藏虎头兰植株高效再生的条件。 结果表明:适宜西藏虎头兰生长的基本培养基为 1/2 MS;种子萌发和原球茎诱导的最适培养基为 1/2 MS+1.0 mg·L-1 6-BA +0.5 mg·L-1 NAA,培养 50 d 后,有 95.00%的种子发育成原球茎;原球茎增殖的最适培养基为 1/2 MS+2.0 mg·L-1 NAA, 培养 30 d,增殖倍数为 4.25;原球茎的最适分化培养基为 1/2 MS+2.0 mg·L-1 NAA+60 g·L-1土豆泥+0.5 g·L-1活性炭, 培养 10 d,不定芽发生率为 98.33%,培至 40 d,幼苗生根率为 94.67%;试管苗在温度 20℃、光照时间 12 h·d-1、光照强度 2 000 lx 的条件下培养,苗长势好,叶片生理性焦尖发生率仅为 3.33%;以腐殖土作为栽培基质,试管苗的移栽成活率为 97.78%。该研究结果为保护西藏虎头兰野生资源和工厂化育苗提供了科学依据和技术支持。

submitted time 2018-07-18 From cooperative journals:《广西植物》 Hits3476Downloads577 Comment 0

10. chinaXiv:201808.00147 [pdf]

云南被子植物新资料

喻丁香; 杨锦超; 肖之强; 杜凡
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Plant Protection

植物资源调查是探讨系统发育、植物区系进化历史和亲缘关系的基础,是我国植物研究工作的重要任务之一。虽然我国在植物资源调查方面有了丰富的积累,并以《中国植物志》和各地方植物志为代表,但部分偏远地区的植 物资源状况仍然缺乏数据。通过形态特征比较分析,发现云南省被子植物新记录 3 种。柳叶黄肉楠 (ActinodaphnelecomteiAllen)原分布四川、贵州、广东(乳源)、广西,云南省丘北县为其新记录点;八角樟(Cinnamomum ilicioidesA.Chev.)原分布广东、海南、广西,越南北部,云南省西双版纳傣族自治州勐腊县为其新记录点;贵州山 核桃(CaryakweichowensisKuangA.M.Lu exChangetLu)原分布贵州安龙、望谟、册亨、兴义等,云南省丘北县为 其新记录点。柳叶黄肉楠和八角樟在云南的新分布点是对我国樟科薄弱地带的补充,为分析滇产原始种类对相关属的起源发生和中国樟科分类学研究提供了新材料;贵州山核桃在物种层面上对确定贵州山核桃与喙核桃 (Annamocaryasinensis)两者之间的联系提供了新的案例,并为云南发展山核桃(C.cathayensis)生产提供了种质资源。

submitted time 2018-07-18 From cooperative journals:《广西植物》 Hits2913Downloads505 Comment 0

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