Heavy Metals in Soil and Crops of an Intensively Farmed Area: A Case Study in Yucheng City, Shandong Province, China

lThe study was supported by the Knowledge Innovation Foundation of the institute of Geographical Sciences and Natural Resource, Chinese Academy of Sciences (Grant No. 200906002) and Key Directional Project of Knowledge Innovation of Chinese Academy of Sciences (Grant No. KSCX2-YW-N-46-01). The authors would like to thank to Luke Driskell for his kind help and hard work on English language polishing of the article.

Determining of the delay time for a heating ventilating and air-conditioning plant using two weighted neural network approach

This paper presents an two weighted neural network approach to determine the delay time for a heating, ventilating and air-conditioning (HVAC) plan to respond to control actions. The two weighted neural network is a fully connected four-layer network. An acceleration technique was used to improve the General Delta Rule for the learning process. Experimental data for heating and cooling modes were used with both the two weighted neural network and a traditional mathematical method to determine the delay time. The results show that two weighted neural networks can be used effectively determining the delay time for AVAC systems.

Determining of the delay time for a heating ventilating and air-conditioning plant using multi-weights neurons approach

This paper presents an multi weights neurons approach to determine the delay time for a Heating ventilating and air-conditioning (HVAC) plan to respond to control actions. The multi weights neurons is a fully connected four-layer network. An acceleration technique was used to improve the general delta rule for the learning process. Experimental data for heating and cooling modes were used with both the multi weights neurons and a traditional mathematical method to determine the delay time. The results show that multi weights neurons can be used effectively determining the delay time for HVAC systems.

Operational characteristics of a 1.2-MW biomass gasification and power generation plant

In this study, we analyzed the operational characteristics of a 1.2-MW rice husk gasification and power generation plant located in Changxing, Zhejiang province, China. The influences of gasification temperature, equivalence ratio (ER), feeding rate and rice husk water content on the gasification characteristics in a fluidized bed gasifier were investigated. The axial temperature profile in the dense phase of the gasifier showed that inadequate fluidization occurred inside the bed, and that the temperature was closely related to changes in ER and feeding rate. The bed temperature increased linearly with increasing ER when the feeding rate was kept constant, while a higher feeding rate corresponded to a lower bed temperature at fixed ER. The gas heating value decreased with increasing temperature, while the feeding rate had little effect. When the gasification temperature was 700-800C, the gas heating value ranged from 5450-6400kJ/Nm3. The water content of the rice husk had an obvious influence on the operation of the gasifier: increases in water content up to 15% resulted in increasing ER and gas yield, while water contents above 15% caused aberrant temperature fluctuations. The problems in this plant are discussed in the light of operational experience of MW-scale biomass gasification and power generation plants.

黄土高原土壤干层评定指标的改进及分级标准

土壤干层是黄土高原普遍存在的特殊土壤水文现象,研究其现状、成因、防治、调控措施等对科学认识区域植被承载力、土地生产力以及低效林草改造和可持续植被建设等有重要理论与生产指导意义,而合理通用评判指标与分级标准是开展土壤干层研究的基础。目前黄土高原土壤干层尚无统一评判指标与分级标准,给区域土壤干层研究带来困难。本文在已有研究成果的基础上,提出用土壤有效水饱和度/不饱和度作为土壤干层评判指标,并给出其分级标准。该评判指标计算简单,具通用性和可比性,可望成为土壤干层的通用评判指标。

黄土丘陵区地形、土壤水分与草地的景观格局(英文)

在黄土丘陵区,地形因素和土壤水分是决定草地景观格局的主要因素,同时草地景观格局在不同尺度上影响着景观中的流。地形因素、土壤水分和草地结构在不同尺度上有着密切的联系,研究它们之间的关系对于了解生态系统的过程十分重要。针对黄土高原异质化的草地群落结构,选取黄土丘陵区经过20多年自然封育形成的天然草地,从坡面尺度对景观格局进行了调查研究,在地形因素、土壤水分和草地结构中选取了有代表性的指标14个,用多元统计分析对选取的指标进行了主成分分析和聚类分析。聚类分析将样方分成3种植被类型,不同植被类型的海拔、坡度、20~140cm土壤含水量以及物种丰富度和生物多样性存在显著性差异。相关分析表明:海拔对0~300cm土壤含水量影响显著;海拔对草地群落盖度,坡位、坡向对草地群落的物种丰富度和生物多样性有着重要影响;而草地群落的物种丰富度和生物多样性与0~100cm土层的含水量关系密切。

冰期间冰期转换过程中陆地碳库的演化规律研究

Terrestrial carbon pool mainly consists of three parts: the active carbon pool of the vegetation，soil carbon pools and the lithosphere carbon pool of less activity. Under natural conditions，vegetation carbon pools，soil carbon exchange with atmospheric carbon pool directly，the lithosphere participate in the global carbon cycle by weathering Our research have coverd the soil organic carbon density，plant biomass (carbon density)，plant net primary productivity of past 40 ka，and the magnetic susceptibility，grain size，weathering of silicate carbon consumption of past 140 ka. This study has achieved a number of conclusions as shown below. 1 Silicate weathering CO2 consumption in the long-term fluctuations with a similar deep-sea δ18O record，demonstate that it not only can be used as one of the instructions of terrestrial carbon pool，even can be used as indicators of global environmental change; silicate weathering CO2 consumption and susceptibility shown a clear relationship between lag or lead at different times，it maybe lies on how the climate change. 2 Soil carbon pools in line with the global climate on long-term，but the relationship between soil carbon density and climate change was not obvious in short-term change，generally lags behind the changes in other climatic proxies. 3 Carbon density of vegetation and other proxy indicators of climate have good consistency. In the study period，perform the cycle of glacial and interglacial completely，but because of the ancient vegetation of accurate information is difficult to obtain，it did not reflect rapid response to climate change. 4 Cooling events is conducive to soil organic carbon accumulation but not conducive to weathering and vegetation growth. High temperature environment is not conducive to the accumulation of soil organic carbon. 5 In the deglacial time from the last glacial maximum to the Holocene，weathering carbon consumption seems earlier than vegetation and soil organic carbon in the fluctuant increase.Does it imply that the effects of silicate weathering is an important factor to the global carbon cycle and global climate change? It is worth further research.

资源异质性环境中植物克隆生长的描述与模拟

植物克隆生长型主要由遗传结构决定，不同的克隆植物具有不同的克隆生长型，同时植物的克隆生长型又依具体生境和个体发育阶段不同而变化。Harper认为植物构件的结构由分枝角度、节间长度和芽的成活率决定。大量的研究表明克隆植物生长型主要由3个形态参数决定：节间长度、分枝角度和分枝强度。 植物的生境条件无论在时间还是空间上都是异质性的，即使在很小的尺度上这种异质性也是存在的。在这种具有异质性的生境条件下几乎所有植物都有表型可塑性。植物的表型可塑性是指植物在不同的环境因子条件下，在形态、生物量、生理等方面产生的一系列不同。表现型可塑性是植物种群克服环境异质性的重要途径，也是克隆植物实现觅养行为的途径。克隆植物的觅养行为是通过根茎或匍匐茎的长度和分枝强度的变化以及生物量的分配来实现其迁移和对生境的选择，从而将分株安置在各种微环境中。 克隆植物构型的可塑性可使它在土壤水分斑块性分布的环境中通过克隆生长，调整对不同斑块的土壤水分获取对策。在一田间实验中，匍匐茎草本蛇莓（Duchesnea indica Focke）经历了不同土壤水分水平（土壤最大含水量的40%、60%、80%、100%等）处理，以研究土壤水分对蛇莓克隆构型的影响。结果表明：间隔子长度、分株密度、分枝角度和分枝强度呈二次曲线变化，土壤含水为最大含水量的80%为最适生境。 克隆植物构型的可塑性可使它在养分斑块性分布的环境中通过克隆生长调整相应于对不同斑块的养分获取对策。在一田间实验中，蛇莓经历了不同土壤养分水平（高、中、低和对照）处理，以研究土壤养分对蛇莓克隆构型的影响。结果表明：随着土壤养分水平的增加，间隔子的长度、分枝角度均逐渐降低，分枝强度和分株密度增加。 克隆植物构型的可塑性可使它在不同光强的环境中通过克隆生长，调整其对不同光强的资源获取对策。在控制性光资源异质性生境（模拟浓密林荫、稀疏林荫、农田间套作、裸地等）下，研究和模拟了光资源的时空异质性和蛇莓的克隆可塑性变化。结果表明：随着光照强度的增加，间隔子长度的长度逐渐降低，分枝角度、分株强度呈二次曲线变化。 克隆植物构型的可塑性可使它在不同海拔的环境中通过克隆生长，调整其对不同海拔的资源获取对策。在一海拔高度实验中，匍匐茎草本蛇莓经历了不同海拔(400 m、800 m、1200 m和1600 m)处理，以研究不同海拔对蛇莓克隆构型的影响。结果表明：随着海拔的增加，间隔子长度、分株密度、分枝角度和分枝强度呈二次曲线变化。 从克隆植物生长环境（小气候）定量分析了克隆植物生长必需资源如水分、养分、光强、海拔等的变化特性。具体描述和分析了异质环境尺度的大小和等级数。在前人研究成果的基础上，验证了克隆植物生长必需资源分布异质性的数学模型并建立相应的运算模块。在不同水分、养分、光强和海拔等异质性生境中，蛇莓克隆构型相关特征的可塑性变化可用动态Logistic模型进行模拟和预测，拟合效果较好。结合植物对环境异质性的利用对策，对所揭示的蛇莓克隆构型可塑性进行了讨论。 用分形技术描述了蛇莓在资源斑块性分布的生境中，通过克隆生长调整相应于对不同斑块的资源获取对策。植物克隆构型的形态特征在一定尺度范围内具有自相似特征。蛇莓克隆构型的分形维数直接反映了在异质性生境中蛇莓克隆生长的差异。蛇莓克隆生长越发达分形维数越高。相对小的分形维数，反映出蛇莓克隆生长相对较弱。基于计算机图像技术和分形理论，建立了植物克隆生长分形度量的计算机模型，实现了对植物克隆生长过程的计算机模拟。模拟的蛇莓克隆生长形态与实际生长不仅具有相近的分形维数，而且形态也非常相似。利用克隆生长模型的预测能力克服实验生态学难以逾越的某些研究盲点，其研究成果将对克隆植物利用资源异质性的生态对策研究具有重要的指导意义。

内蒙古温带草原群落结构和生态系统功能对火烧、氮素添加和地形的响应

我国北方温带草原是欧亚大陆草原生物群区的重要组成部分，对于区域和全球的碳循环和平衡起着重要的作用。频繁的自然或人为干扰能够改变草原生态系统的群落结构和生态系统功能，从而影响生态系统为人类提供的产品和服务。本研究选取位于内蒙古多伦县的半干旱温带草原，研究火烧、氮素添加和地形以及它们的综合作用对该地区植物生产力、植物多样性、盖度和土壤呼吸的影响；另外，我们比较研究了由于地形因素而存在于草原地区的林地群落与其邻近草地的碳氮库和循环；旨在探讨我国北方温带草原地区人为干扰对草原生态系统结构与功能的影响以及该地区林地和草地碳氮库和循环的差异机理，以期为模型模拟本地区的生态系统碳循环提供理论依据和数据支持，具体研究结果如下： 1. 2006–2008 年，通过研究植物多样性和盖度对地形、火烧和氮素添加及其交互作用的响应，结果表明：半干旱草原植物物种数、香农威纳指数、均一性指数和盖度均表现出显著的年际变化。坡下的物种数、香农威纳指数和均一性指数均低于坡上。坡下较高的羊草(Leymus chinensis)、冰草(Artemisia frigida)、唐松草(Thalictrum petaloideum)和冷蒿(Agropyron cristatum)的盖度导致坡下的群落总盖度、禾本科草和非禾本科草盖度分别比坡上高22.5%、9.6%和13.2%。春季火烧提高了物种数、香农威纳指数和均一性指数。火烧对群落总盖度影响较小是由于火烧后非禾本科草冷蒿盖度的降低抵消了禾本科草羊草、冰草和针茅(Stipa kryroii)盖度的增加。施氮肥后物种数、香农威纳指数和均一性指数均降低。禾本科草羊草、冰草和针茅以及非禾本科草唐松草盖度的增加导致施肥后群落总盖度、禾本科草和非禾本科草的盖度分别增加了23.6%、35.1%和21.2%。火烧对禾本科草和非禾本科草盖度的作用受地形和氮素添加的影响。地形、火烧和氮素添加对植物盖度的影响主要受土壤水分调控。 2. 2005–2008 年，通过研究净初级生产力(NPP)对火烧、氮素添加和地形及其交互作用的响应，结果表明：半干旱草原的NPP 具有显著的年际变化。火烧后地上净初级生产力(ANPP)、地下净初级生产力(BNPP)和BNPP/ANPP 分别增加了12.8%、22.2%和14.9%。ANPP 的提高是由于火烧后禾本科植物(主要是羊草、冰草和针茅)生物量的增加。与之相反，火烧降低了非禾本科草，特别是冷蒿的生物量。氮素添加提高了ANPP (54.8%) ，对BNPP 没有影响，导致施氮肥后BNPP/ANPP 显著降低(33.4%)。禾本科草羊草、冰草和针茅以及非禾本科草唐松草生物量的增加，是氮素添加提高ANPP 的主要原因。坡下的ANPP 和BNPP 分别比坡上高14.1%和8.2%，但地形对BNPP/ANPP 没有影响。坡下ANPP 的提高主要是由于坡下禾本科草羊草、冰草以及非禾本科草唐松草、冷蒿的生物量高于坡上。氮素添加和地形影响ANPP 和BNPP/ANPP 对火烧的响应。火烧、氮素添加和地形对NPP 和植物碳分配39%–75%的综合效应可由这三个因素的简单加和效应来解释。 3. 通过研究2005 和2006 年生长季内土壤呼吸对地形、火烧和氮素添加的响应，结果表明：坡下的季节平均土壤呼吸比坡上高6.0%。春季火烧在整个生长季内促进土壤呼吸，平均增幅达23.8%。另外，火烧对土壤呼吸的效应受到季节和地形的影响。施用氮肥增加了11.4% 的土壤呼吸。火烧和地形对土壤呼吸的影响主要受土壤水分和植物生长的调控；而施氮肥后土壤呼吸的增加，主要是由于氮素添加促进植物生长后根系活性和呼吸的提高。 4. 2006–2007 年，通过对林地群落及其邻近草原生态系统土壤温度、土壤水分、土壤机械组成、地上和地下生物量、凋落物现存量、土壤碳氮储量、土壤呼吸、氮矿化和土壤微生物生物量的比较研究，结果表明：林地的土壤温度比草地低5°C，而其土壤水分却比草地高3.1%(绝对差异)。尽管林地(11,928.1 g m–2)和草地(11,362.2 g m–2)的土壤碳储量差异不显著，由于林地较高的植物生产力导致其碳储量高于草地。与草地相比，林地具有较高的凋落物现存量及碳氮含量、土壤无机氮含量、矿化氮的累积量、微生物生物量碳、微生物生物量氮、土壤呼吸和微生物呼吸。草地和林地的氮矿化速率没有显著差异。由地形因素引起的水分差异对于调控林地和草地生态系统碳氮库和循环(土壤碳氮储量、BNPP、矿化氮的累积量)具有重要作用。林地与草地生态系统碳储量的差异影响了我国北方草原地区碳的评估。

次生植被下土壤活性有机碳组分季节动态研究

为了揭示不同类型植被下土壤有机碳及其活性组分季节动态变化及其特点，探讨不同的植被恢复模式对土壤有机碳组分的影响，分析影响土壤有机碳组分变化的因素，评估土壤有机活性有机碳组分参数在植被恢复过程中土壤质量监测的可靠性，为植被恢复及低效林改造技术提供理论依据。本研究选择岷江上游大沟流域的几种人工林（云杉林、油松林、华山松林、日本落叶松林）以及次生落叶阔叶灌丛下土壤，通过剖面机械分层取样，测定土壤总有机碳（TOC）和三种活性碳组分微生物碳（SMBC）、水溶性碳（WSOC）、易氧化碳（EOC）等来反映土壤变化特点。主要结果是： 1. 土壤有机碳含量平均在15.48~25.46 g kg-1之间在5月份时含量最低，随生长季的开始，有机碳含量逐渐增加，到9月份时含量达到最大值；由于新形成的凋落物不能被迅速分解利用补充土壤碳库，而原有碳库经历一个生长季的分解利用，因此，生长季末期即11月份的含量较小；土壤微生物碳含量平均在132.78~476.73mg kg-1之间，9月份和11月份含量都比较高；水溶性碳在生长季中逐步增大，含量在51.95~77.18 mg kg-1之间，到11月份时达到最大值；土壤易氧化碳平均含量在3.74~5.79g kg-1之间，含量最低值出现在5月份，但和其他碳组分不同的是其在7月份时含量较高。 2. 土壤有机碳及其活性碳组分大小关系为：TOC>EOC >SMBC>WSOC；比值约为300：70：5：1。 3. 土壤不同层次间比较，土壤碳指标都表现为随土壤深度增加而逐渐减小, 表层积聚作用明显。 4. 对土壤总有机碳量与活性碳组分以及活性碳之间进行了相关分析表明，土壤总有机碳含量与土壤微生物量碳、水溶性碳、易氧化碳之间的相关性均达到显著水平（P<0.05），有机碳总贮量很大程度上制约着土壤活性碳组分。土壤微生物量碳、水溶性碳、易氧化碳两两之间也都存在着显著相关关系（P<0.05），并随着不同植被类型或立地条件因子发生变化而变化。 5. 土壤有机碳及其活性组分与土壤养分状况之间的相关性分析发现，随着海拔、坡向或者植被类型的改变，其林下土壤有机碳及其活性组分与土壤养分的相关性也发生较大的变化。总体而言，岷江上游地区海拔、坡向、土壤自然含水量、植被盖度、凋落物厚度、土壤全N对次生林下土壤有机碳及其组分有重要影响。而AP、AK、C/N对土壤碳变化变化影响较小。 6. 通过不同海拔、坡向以及植被类型之间的综合比较分析发现，土壤微生物碳SMBC和水溶性碳WSOC比TOC和EOC更能敏感地反映出比较敏感的指示林下土壤质量的变化。 In order to reveal seasonal dynamics of soil labile organic carbon under different secondary vegetation, to analyze effect of different vegetation restoration pattern on soil organic carbon and its fractions, and to find the factors influencing changes in soil organic carbon and its fractions, further to estimate those parameters reliability for soil quality monitoring in the process of vegetation restoration. Soils were selected from several plantations, including Picea asperata Pinus tabulaeformis, Pinus armandii and Larix kaempferi and secondary shrub in Dagou Watershed of the upper reach of Minjiang River. The measurement of TOC, SMBC，WSOC and EOC were made, because these parameters can reflect change of soil characteristics. The major results are: 1. There were the lowest soil organic carbon and its labile fractions contents in May. At the time of growth initiation, they increased gradually and reached maximum in September. After that the soil organic carbon content decreased. Because current litter couldn’t be rapidly decomposed, and supplemented into carbon pool, while intrinsic carbon pool experienced decomposition and utilization of growth season, Which led a decrease in soil organic carbon content in November. Average value was 15.48~25.46 g kg-1; average SMBC content was 132.78~476.73mg kg-1.There were higher SMBC content in September and November as compared with other times; Water soluble organic carbon content increased from 51.95 mg kg-1 in May to 77.18 mg kg-1 in November; EOC content was lowest in May y. Average value was 3.74~5.79g kg-1. Differeing from other parameters of carbon fractions, EOC content was higher in July. 2. The content of soil organic carbon and its labile carbon fractions ranked as follows：TOC>EOC >SMBC>WSO，and ratio was about 300：70：5：1. 3. Consider as soil different layers，all of the parameters decreased gradually with increasing soil depth, thus displayed a significant accumulation in the surface layer soil. 4. Correlations coefficient analysis revealed that, TOC significantly correlated with SMBC, WSOC and EOC indicating total storage of organic carbon limited soil labile carbon fractions in great extent. On the other hand, there were significant correlations between SMBC，WSOC and EOC. But these relationships changed with vegetation types and/or environmental conditions. 5. The relationships between soil organic carbon and its labile fractions and soil nutrient traits changed with altitude，slope aspect and vegetations. Therefore our results suggested that altitude，slope aspect，soil natural water content，vegetation coverage, litter thickness and soil total nitrogen play a important role change in soil organic carbon and its fractions in upper reaches of Minjiang River. While AP、AK、C/N slightly influenced soil carbon. 6. Our results, on the other hand suggested that SMBC and WSOC are more sensitive to the change of altitudes, slope aspects, vegetation types than TOC and EOC, thus two parameters may be good index reflecting change of soil quality. These results provide insights into theoretical and technological evidences for the vegetation regeneration restoration and improvement of low-quality and benefit forest in the upper reaches of Minjiang River regions.