离子型稀土闭矿区土壤铵态氮富集特征

离子型稀土开采使用的浸矿剂(硫酸铵)造成土壤铵态氮(NH₄⁺-N)残留,带来严重的氮污染,危及生态环境和人体健康,导致稀土矿开采受限。为明确已开采矿区土壤中NH₄⁺-N的富集特征及其影响因素,选择江西省赣州市龙南县一个已闭矿4年的原地浸矿离子型稀土矿山,在山体不同坡位布点,自土表至矿体底板(土体与基岩交界处,深度为5.5～9.7 m)分层采样,并测定了土体中的NH₄⁺-N及其相关的土壤性质。结果表明,矿区土壤NH₄⁺-N含量范围为2.32～1 056.44 mg·kg^-1(263.12±301.59mg·kg^-1),是自然和农田土壤的数倍甚至上百倍。从土体分布来看,矿体部分土壤NH₄⁺-N含量高于其上部土壤,不同土层间差异显著。从不同地形部位来看,NH₄⁺-N的平均含量坡顶>坡...     

Diversity and Characterization of Potential H2-Dependent Fe(Ⅲ)-Reducing Bacteria in Paddy Soils

Microbial ferric iron reduction, with organic carbon or hydrogen as the electron donor, is one of the most important biogeochemical processes in anoxic paddy soils; however, the diversity and community structure of hydrogen-dependent dissimilatory iron-reducers remain unknown. Potential H2-dependent Fe(III)-reducing bacteria in paddy soils were explored using enrichment cultures with ferrihydrite or goethite as the electron acceptor and hydrogen as the electron donor. Terminal restriction fragment length polymorphism (T-RFLP) analysis and cloning/sequencing were conducted to reveal bacterial community structure. Results showed that Geobacter and Clostridium were the dominant bacteria in the enrichment cultures. Fe(III) oxide mineral phases showed a strong effect on the community structure; Geobacter and Clostridium were dominant in the ferrihydrite treatment, while Clostridium spp. were dominant in the goethite treatment. These suggested that H2-dependent Fe(III)-reducing bacteria might be widely distributed in paddy soils and that besides Geobacter, Clostridium spp. might also be an important group of H2-dependent Fe(III)-reducing microorganisms.     

动物园环境丰容对恒河猴行为的影响

为了探索环境丰容对恒河猴行为的影响,对比观察研究了山西阳泉南山公园动物园猴山环境丰容条件和单独笼养的恒河猴行为的变化,发现环境丰容对恒河猴有明显影响,表现在丰容环境条件下恒河猴积极行为增加,消极和异常行为减少,结果表明实施环境丰容有利于恒河猴天性的恢复与展示。     

Effect of range enrichment on performance,behavior, and forage intake of free-range chickens

The aim of the present study was to analyze the effect of range enrichment (trees or tall grass stand) on the performance and herbage intake of free-range chicken. This trial was conducted in 2 different seasons (winter and summer) comparing a standard free-range system with 2 kinds of range enrichment: a stand of sorghum (a tall grass) and olive trees. Two hundred fifty male naked neck chickens were used in each season and system; performance, behavior, forage intake, and body lesions were recorded. Productive performance was not affected by range enrichment. However, in the presence of trees or tall grass stand, no predation losses were experienced; whereas, in the standard paddock, cases of predation by raptors or crows were registered, mainly during the first period of rearing. Consequently, mortality rate was significantly lower in the enriched environment. Control chickens stayed indoors more rather than forage in the pasture, whereas, in enriched environments, birds spent more time outdoors and widely exploited the available pasture. Forage intake was significantly influenced by rearing system and season; chickens reared under olive trees had higher herbage ingestion, exploring the available area up to almost 50 m from the hut. With the olive trees, chickens also showed the lowest frequency of foot and breast damage.     

早开堇菜对镉污染的耐性及其富集特征

为研究早开堇菜(Viola prionantha)对镉(Cd)的耐性及其对Cd的富集特征,使用盆栽方法对早开堇菜进行不同浓度水平Cd处理。结果表明,低浓度Cd(≤10 mg·kg-1)促进早开堇菜的生长。当Cd浓度为5 mg·kg-1时,早开堇菜植株地下部分、地上部分生物量显著高于对照(P0.05),达到最大。随Cd处理浓度的升高,其叶绿素含量逐渐下降,超氧化物歧化酶(SOD)、抗氧化物酶(POD)、过氧化氢酶(CAT)活性先升高后降低,丙二醛(MDA)含量则先下降后上升。当Cd处理浓度≤10 mg·kg-1时,SOD、POD、CAT表现出较高的活性,与对照无Cd处理相比,MDA含量未显著增加(P0.05),叶绿素合成也未受到显著抑制,说明早开堇菜对Cd污染有较强的耐性。本研究中,早开堇菜对Cd的富集系数和转运系数均大于1.0。当Cd处理浓度为5 mg·kg-1时,早开堇菜植株地上部Cd含量为113.083 mg·kg-1,达到了Cd超富集植物的筛选标准。因此,早开堇菜在修复Cd污染土壤方面具有一定的潜在应用价值。     

坡地土壤侵蚀与养分流失过程的研究

本文采用人工降雨室内试验,研究了坡地土壤侵蚀与有机质、全氮和有效磷养分的流失过程。坡度、雨强对其流失过程的影响;比较分析了裸露坡地及沙网覆盖两种处理的土壤侵蚀与养分流失过程。结果表明:随坡度,雨强增大,养分流失量也增加;试验小区覆盖纱网消除雨滴动能后,土壤养分流失量比裸露坡地减少60%左右;养分流失量与土壤流失量呈正相关,多数泥沙样中有效养分的含量高于土壤中养分含量,尤以有效磷更为显著。     

中国白浆土研究Ⅱ.无定形铁、锰、铝氧化物特性及其元素地球化学分异

本文主要研究了白浆土中无定形态铁、锰、铝氧化物特性及其元素的地球化学特征。结果表明：（１）游离态、活性态及络合态的铁、锰、铝氧化物都向着粘粒中富集。其中游离态及活性态中，Ａｌ２Ｏ３富集最强烈，Ｆｅ２ｏ３次之，ＭｎＯ最弱。（２）铁、锰、铝氧化物的活性是ＭｎＯ高于Ｆｅ２Ｏ３，而Ａｌ２Ｏ３主要取决于ＰＨ值，同时也受其它因素的影响。ＭｎＯ和Ｆｅ２Ｏ３在活性上的差异，不仅取决于两者在标准氧化还原电位的差异上     

组培环境CO2增施监控系统的设计与试验

为改善组培苗的生长发育环境,探索CO₂富集等环境因素的影响,设计制作了CO₂适时增施监控系统,并以葡萄组培苗为对象,利用本控制系统与传统组培方式进行了对比试验。结果表明:系统工作稳定、正常,能够有效地将CO₂浓度控制在设定的(800～1200)μL/L范围内,满足组培苗光合作用的需要;在CO₂富集环境中,组培苗生长健壮、发育良好,光合自养能力显著增强     

温室蔬菜高架栽培CO2供气负荷计算与设备选型方法

针对温室CO_2供给设备容量设计缺乏相关理论和设备配置的相关规范,在分析CO_2恒定浓度控制模型、低浓度控制模型、恒定供气流量控制模型的基础上,探索建立了温室内CO_2平衡模型,结合作物对CO_2的需求和大型连栋温室蔬菜高架栽培的土壤CO_2释放量低等特点,提出了温室CO_2施肥供气负荷计算方法;以天然气锅炉的回收烟气和液态CO_2为气源,提出了以CO_2供应为目标的天然气锅炉功率和液态CO_2储液罐容积计算方法,为相应设备的设计选型提供了理论依据。以栽培面积49 200 m~2,容积329 640 m~3的文洛型温室为案例,采用该文建立模型进行计算表明,在CO_2施肥恒定流量控制模式下,设定最低控制CO_2体积分数为600×10~(-6) m~3/m~3条件下,白天仅需运行1台额定蒸发量为10 t/h的天然气锅炉就可满足CO_2施肥需求;用液化CO_2施肥,在CO_2低浓度控制模式下,设定最低控制CO_2体积分数为500×10~(-6) m~3/m~3条件下,则需要配备容积为20m~3的储液罐。实际运行情况表明,该文建立的CO_2施肥供气负荷计算与设备选型方法切实可行,满足实际生产的要求。     

Environmental enrichment reduces maladaptive risk-taking behavior in salmon reared for conservation

Hatcheries often produce bold fish that are maladapted to survive in the wild, as absence of predators and selection for fast growth tend to favour risk-taking behaviors. Not surprisingly, losses of hatchery fish through predation can be high immediately after release and this may account for the failure of many ex-situ fish conservation programmes. For supportive-breeding to be useful, it is essential that released fish are able to display natural behaviors. We compared the performance of juvenile Atlantic salmon reared in environmentally-enriched tanks receiving natural prey and subjected to simulated predator attacks with fish reared under standard hatchery conditions while keeping densities constant. No differences were detected between controls and environmentally enriched fish in survival, final size or nutritional status. Yet, changes in rearing conditions had rapid and marked effects on risk-taking behavior. Environmentally enriched fish were 2.1 times less willing, and took significantly longer to leave shelter, than controls within two weeks of enrichment. Thus our study indicates that it is possible through environmental enrichment to modify at least one component of fishes’ behavior known to have clear adaptive implications, i.e. the propensity of hatchery-reared fish to take excessive risks. Ex-situ conservation could therefore benefit from rearing fish in naturalized, structurally complex environments with natural prey to promote the development of more natural behaviors.