世纪之交土壤学研究的挑战和契机——从第16届世界土壤学大会看土壤？…

第１６届国际土壤学大会包括全会和４５个分会,内容涵盖土壤所有分支并反映了本世纪土壤学的进展。本文综述了土壤学在全球资源与环境问题中的重要地位,分析了世纪之交土壤学面临的挑战和契机,提出土壤学只有拓展与其它学科以及社会的联系,服务于社会的可持续发展,保持自己的特色并在基础研究和应用研究中不断创新,才能在未来更好地生存和发展。     

基础土壤学研究的方法论思考:基于土壤化学的视角

长期以来,不少人片面地认为,土壤学在学科属性上仅是应用型的,在研究手段上仅是实验型的,在研究方法上必须是整体综合的。本文系统地分析了这些片面认识对土壤学发展的危害,提出土壤学发展应特别强调"分析"的方法,并在深入分析的基础上实现自然而系统的综合。阐述了土壤学研究的三个基本观点:一是充分认识土壤系统的特殊性根基在于其对物质亚原子结构的重大影响。与普通水溶液中的情况相比,土壤中的离子、原子和分子在本质上已发生了很大变化。所以,如果土壤确实从亚原子尺度上改变了物质的结构与性质,开展土壤学中独特的量子效应研究将是重要的。其次,充分考虑土壤系统的特殊性,在方法上应从宏观尺度、介观尺度、分子尺度至亚原子尺度对土壤进行逐级分解简化,并借助于量子力学原理和方法,最终,在亚原子尺度上彻底剖析土壤,以获得土壤学自己的科学基础。第三,以土壤中独特的量子效应为基础的研究,可构建"亚原子结构—土壤微观机制—宏观效应"三者间的直接关联,由此实现土壤中不同尺度间科学原理的自然转换,最终构建独立的土壤学知识体系。     

土壤化学现象中的能量关系

自然界中的各种化学现象,归根到底是能量的各种形式的表现及其相互转化,土壤中的化学现象,作为化学现象中的一种特殊表现形式,也应遵循这些基本规律。在土壤学发展的早期,人们只能够从表面上孤立地看待土壤中的各种化学现象,以后随着物理化学和胶体化学的理论和方法的进展及其在土壤学研究中的应用,从五十年代起,开始从能量关系方面,研究土壤化学现象的本质,并且在最近几年来,发展成为土壤化学研究中极为活跃的一个领域。     

景观生态学原理在土壤学中的应用

从研究的背景、本质及内容来看 ,现代土壤学有着鲜明的景观生态学内涵 ,研究离不开景观生态学观点的指导。土壤研究的尺度、土壤性质的时空异质性及过程的动态性决定着在大尺度上土壤学研究必须采用景观生态学的观点 ,这也是土壤学发展的一个必然趋势。土壤学汇集了众多学科的前沿研究方法 ,而景观生态学在理论上为土壤学研究拓展了更大的空间。作为学科交叉及研究动态 ,文章给出了景观生态学和土壤学研究相关联的许多热点研究动态 ,同时讨论了土地利用、土壤侵蚀、土壤面源污染等研究的景观生态学本质 ,从理论与实践上指出了景观生态学原理对土壤学研究的意义。     

中国土壤化学的研究与展望

回顾土壤化学中重要研究领域的研究进展,可为21世纪土壤科学的长远发展提供基础学科分支的理论依据。本文在简短回顾我国土壤化学发展历程的基础上,总结讨论了近年来我国土壤化学的研究特点、现状及部分进展,并据此对该领域的未来研究趋势及重点发展方向作了概括性展望。综合分析认为,对土壤进行宏观调控要以土壤微观性质的认识为前提。新近基于分子尺度微观光谱技术对土壤微观性质的原位观测及认识的飞跃是近年来我国土壤化学研究领域迅速发展的基础;近代土壤学、环境科学、生态学、生物地球化学、化学、生物学以及地质医学等多学科的交叉与渗透又进一步拓展了传统土壤化学研究的领域,促进了土壤化学多个分支学科的形成和发展;立足农业生产,同时着眼于人类生存环境转变,建立具有中国特色的可变电荷土壤化学理论与技术体系,完善现代土壤学理论,是今后中国土壤化学研究的重要发展方向。     

现代土壤学的发展趋势与研究重点

当前土壤学研究的主要特点表现为学科的结合日益密切;分支新学科不断涌现、学科内部分工更加细化;研究手段和方法不断改进;长期定位研究愈来愈受到重视等方面。随着科技进步和农业以及土壤学本身的不断发展,土壤学研究表现出以下发展趋势:研究方法的规范化、标准化和定量化;新技术、新方法的应用更加广泛;国际合作研究不断加强;更重视土壤资源高效利用与生态环境保护。未来10~15年,我国土壤学发展的重点研究内容可集中在以土壤质量提升与调控为核心的土壤养分资源高效利用、土壤有机质提高机制与生产力关系、土壤肥力演变规律与评价体系、障碍及低产土壤改良、土壤污染环境及修复重建等方面。     

环境土壤学——回顾与展望

环境土壤学是一门新兴的、土壤学和环境科学交叉融合的综合性学科，其研究重点从早期服务于农业安全生产发展至现在的土壤环境与健康，本文从土壤外源物质侵袭和土壤质量演变对土壤环境影响等方面回顾了环境土壤学发展历程。土壤污染物对土壤环境质量影响是以土壤元素背景值和环境现状调查为基础，以明确污染物形态，揭示土壤反应过程机制，评估污染效应，开展土壤环境修复工程为主线不断发展更新。土壤质量演变研究中碳、氮、硫、磷元素循环从土壤肥力和农业非点源污染的探讨拓展至土壤对全球气候变化的适应与响应；土壤退化研究则从对土壤生产力或功能丧失的研究发展至全球气候变化背景下农业发展可持续性及土壤生态功能的研究。环境土壤学在今后有四个重要发展趋势：提倡多学科交叉融合；评估全球气候变化对土壤元素循环的潜在影响；完善土壤健康评价框架中的土壤环境评价指标建立；学科发展服务于国家重大需求。     

提升对土壤认识, 创新现代土壤学

土壤是农业生产的基础,是人类赖以生存的基石,也是人类食物与生态环境安全的保障。随着现代科技和国家社会经济的快速发展,土壤的地位与功能正在发生变化。本文基于土壤与土壤学科及国民经济发展需求的关系为出发点,指出了当前对我国土壤的重要性认识正在从农业生产向环境安全、资源利用、生态健康及全球变化等方向转变与提升。同时,明确了现代土壤学的内涵和创新现代土壤学的战略思想,全面、系统、前瞻性地提出了现代土壤学的研究前沿与特点,以及现代土壤学研究领域所面临的挑战与展望,为我国现代土壤学的发展指明了方向。     

中国科学院土壤工作会议

中国科学院于11月20-28日在江苏无锡召开了有土壤学、土壤微生物学和植物生理学的工作者一百余人参加的土壤工作会议,就总结我国所特有的丰富经验,抓住土壤学研究的大西瓜、根据中国的实际发展土壤学、使我国土壤科学位于世界先进地位的问题进行了充分的讨论。     

固碳土壤学的核心科学问题与研究进展

土壤碳固定是当前有关陆地生态系统碳循环与全球变化的地球表层过程研究的重要优先领域。国际社会对全球农业温室气体减排的需求，驱动着土壤学对土壤固碳容量与潜力、固碳与减排的过程与机理的前沿探索，并越来越呈现为一个独特的土壤学新兴分支学科——固碳土壤学（SoilScience of C Sequestration）。本文围绕固碳土壤学的基本科学问题，回顾了最近10多年来，特别是最近5年来国内外关于土壤固碳研究的主要进展，讨论了固碳土壤学中的核心科学问题是土壤固碳容量与固碳作用的机理，论述了土壤物理保护、碳化学结合与碳化学转化稳定与固碳容量及稳定化的关系，提出了土壤-植物（作物）-微生物相互作用是当前固碳土壤学的前沿领域和深化方向，并结合国内对水稻土固碳的研究进展，提出了固碳土壤学的概念性框架，认为我国亟待加强固碳土壤学研究，深入探索我国农业经营管理特色下土壤固碳容量、过程、机理，丰富和发展农业土壤碳循环理论，并服务于全球变化生物学和国家碳管理。     

Some aspects of the history of German soil science

During the 19^th century, soil science in Germany developed from a combination of agriculture and both geology and forestry. Further research developments described in this review include pedology, soil classification and mapping, soil chemistry and mineralogy, soil physics, and ecosystem research. Beside this, the German Society of Soil Science and their relations to the International Society (Union) of Soil Science are shortly introduced.     

Game Changer in Soil Science. The Anthropocene in soil science and pedology.

The venerable science of pedology, initiated in the 19^th century as the study of the natural factors of soil formation, is adapting to the demands of the Anthropocene, the geologic time during which planet Earth and its soils are transitioning from natural to human‐natural systems. With vast areas of soils intensively managed, the future of pedology lies with a renewed science that can be called anthropedology that builds on the pedology of the past but proceeds from “human as outsider” to “human as insider.” In other words, the human in pedology must shift from being a soil‐disturbing to soil‐forming agent. Pedology is well prepared to respond to the challenges of the Anthropocene, given the decades of research on human‐soil relations throughout human history and throughout the period of the Great Acceleration (Steffen et al., [76]). However, quantitative understanding of soil responses to the diversity of human forcings remains elementary and needs remedy.     

”The principles of rational agriculture” by Albrecht Daniel Thaer (1752–1828). An approach to the sustainability of cropping systems at the beginning of the 19th century

The identification of quantitative fertility indicators for evaluating the sustainability of cropping and farming systems has become a major issue. This question has been extensively studied by the German agronomist Albrecht Daniel Thaer at the beginning of the 19^h century. In this paper Thaer's work is set in its historical background, from the end of the 16^th century (Palissy, 1580) to the middle of the 19^th century (Liebig, 1840). Then the paper focuses on Thaer's quantitative and complex fertility scale (expressed in “fertility degrees”), which was based on soil properties, on the requirement of nutrients by plants, and on the cropping system (including crop rotation). Thaer expressed soil fertility and economic results as a function of rye production in “scheffel of rye per journal” (ca. 200 kg per hectare). He also proposed a scale to describe the intrinsic fertility of soil. Thaer used this approach to assess the effect of major German cropping systems on soil fertility. He applied it to eight theoretical systems and nine existing systems in a true modeling approach. Thaer completed the fertility evaluation for the nine existing systems with a detailed economical analysis commenting the limits and potentialities of each system. Thaer's approach was used with success during half a century as it combined numerous empirical findings on soils and fertilization with organic substances in a sophisticated model. Unfortunately and despite effective practical applications, the scientific foundations of Thaer's “Humus Theory” proved definitively false as soon as 1840 when Sprengel and Liebig published on mineral nutrition of plants. Thaer's work deserves to be rediscovered since it approaches the modern issue of the sustainability of cropping and farming systems.     

TRENDS OF SOIL CLASSIFICATION IN TANZANIA I. THE EXPERIMENTAL USE OF THE 7TH APPROXIMATION

A review is made of the trends in soil classification in Tanzania, indicating the need for an alternative to the traditional catena concept. An attempt to use the 7^th Approximation is reported, in view of the demand for high category soil classification, using forty-three typical soil profiles and discussing the particular problems related to placing three intimately studied profiles into the orders Alfisol, Ultisol, and Oxisol. An unrevised version of the 7^th Approximation is not recommended for use in Tanzania. However, by using the central concepts of the system and further defining the soil classes at all levels, the use of the 7^th Approximation could greatly assist in the assessment of the nation's soil resources and the ultimate development of agriculture in this country.     

延河流域主要水文要素时变过程分析

对延河流域降水、径流和泥沙等水文要素从20世纪中叶到21世纪初的年内分配及年际变化进行了时变过程分析。以探求区域植被重建对流域水文过程的影响情况。结果表明,三个水文基本要素都有不同程度的年内分布趋于均匀和年际变化趋缓的趋势。20世纪70-90年代比60年代流域平均面雨量分别减少了10.5%,11.7%和14.0%,年径流量分别减少了19.0%,12.9%和22.6%,年输沙量分别减少了21.1%,46.2%和41.7%。     

Natural functions of antibiotics as “informbiotics”

The discovery of antibiotics is one of the main achievements in the science of 20^th century. However, the question about their natural functions is still unsolved. Recently, the necessity for the transition from the anthropocentric view on antibiotics (destruction of other organisms) to analysis of their signal role in the processes of “fine tuning” was realized. The characteristics of the current state of knowledge about antibiotic functions in natural conditions are given in the present review.     

Modelling the Hydro‐Sedimentary Dynamics of a Mediterranean Semiarid Ungauged Watershed Beyond the Instrumental Period

The development of reliable tools to quantify long‐term sediment budgets is critical to establish adequate environmental and management policies in semiarid Mediterranean regions. In this study, we apply a multidisciplinary methodology to estimate water and sediment yields in ungauged Mediterranean watersheds over a period of scarce instrumental data (i.e. second half of 19^th and first half of 20^th centuries). Runoff and precipitation reconstructions have been obtained using an integrative approach involving synoptic reanalysis models, regional climatic datasets, historical archives and palaeoflood proxies from natural archives. The resulting hydrological reconstruction has been implemented on a hydro‐sedimentary distributed model (i.e. TETIS) to understand the hydro‐sedimentary dynamics in the studied watershed. We highlight that, in our study area, regional‐data (instrumental, historical and sedimentary) based models show higher accuracy in the sediment yield and runoff reconstruction than synoptic reanalysis climate models. The modelled sedimentary dynamics for the studied period respond to a complex interplay between human activities and climate variability. During the 19^th century deforestation and grazing activities combined with higher frequency on extreme runoff events resulted in higher runoff and sediment yield in the period 1863–1900. Over the 20^th century, reduced precipitation and land abandonment led to a decrease in erosion rates and sediment yield although increased in 1945–1960 coinciding with a period of higher frequency of heavy rainfalls. This hydrological response to climate and human activities in the study watershed improves our understanding of plausible future trends of environmental degradation in small Mediterranean watersheds under different land use and climate change scenarios. This article includes supporting information which features an explanation of GILMCLIM downscaling model, The precipitation series resulting from the reanalysis data (Figure S1), an analysis of the different precipitation series used (Table S1) and an extensive explanation of how the relation between Puentes and Valdeinfierno reservoirs was considered. Copyright © 2016 John Wiley & Sons, Ltd.     

Early soil knowledge and the birth and development of soil science

Soils knowledge dates to the earliest known practice of agriculture about 11,000 BP. Civilizations all around the world showed various levels of soil knowledge by the 4th century AD, including irrigation, the use of terraces to control erosion, various ways of improving soil fertility, and ways to create productive artificial soils. Early soils knowledge was largely based on observations of nature; experiments to test theories were not conducted. Many famous scientists, for example, Francis Bacon, Robert Boyle, Charles Darwin, and Leonardo da Vinci worked on soils issues. Soil science did not become a true science, however, until the 19th century with the development of genetic soil science, led by Vasilii V. Dokuchaev. In the 20th century, soil science moved beyond its agricultural roots and soil information is now used in residential development, the planning of highways, building foundations, septic systems, wildlife management, environmental management, and many other applications in addition to agriculture.     

基于序贯高斯条件模拟的土壤重金属含量预测与不确定性评价——以宜兴市土壤Hg为例

土壤重金属含量的定量预测和预测结果的不确定性评价对生态风险评估具有现实意义。将1 155个表层土壤Hg样本分成两个无交集的数据集,309个样本用于模拟,另外864个样本用于验证,运用序贯高斯条件模拟方法对宜兴市土壤Hg的空间分布进行估值和模拟,并通过与传统地统计方法中的简单克里格估值进行对照,同时利用高斯序贯指示模拟探索单点和多点联合的不确定性。结果表明:基于同一个半方差模型,100次序贯高斯条件模拟方法得到的E-type型与简单克里格估值在空间分布上基本一致,两种方法的精度基本相同;随机抽取了第1、25、50、75、100次序贯高斯条件模拟的单次实现,将模拟结果和插值结果与846个点进行验证,5个单次实现的平均预测误差和均方根预测误差略高;以0.15 mg kg~(-1)作为临界阈值的单点超阈值概率虽然较高,但其置信度不足以划定污染区域,在划定污染区域时应采用多点联合概率评估其可靠性。     

Evaluation of Mobility and Dissipation of Mefenoxam and Pendimethalin by Application of CSTR Model and Field Experiments Using Bare and Tobacco Tilled Soil Columns

The soil mobility and dissipation of two pesticides with different physicochemical properties, namely mefenoxam, a systemic fungicide, and pendimethalin a selective herbicide, were determined in bare and tobacco tilled soil columns, which were installed in field conditions for over 125 days. Soil samples were collected at specific time intervals for a 125-day period and the rate of pesticide dissipation and leaching through the soil column was studied. The dissipation half-lives of mefenoxam from the top soil layer in tilled and bare soil columns were estimated at 10.3 and 13.1 days, respectively, while the corresponding half-lives for pendimethalin were 26.7 and 27.5 days, respectively. The dissipation of mefenoxam and pendimethalin from the top soil in tobacco cultivation was faster in comparison with bare soil; however, 120 days after their application, both pesticide residues were detected in the soil. Maximum concentrations of mefenoxam and pendimethalin were observed on the 15^th and 33^rd day, respectively, in the soil layer of 5–10 cm depth and on the 30^th day and 63^rd day, respectively, in the soil layer of 10–15 cm depth. Higher concentrations were observed in bare soil columns. The leaching of both pesticides was simulated with the continuous stirred tank reactor (CSTR) in series model. The simulated peak concentration and peak time for both pesticides fitted reasonably well to the experimental values.