Effects of N Forms and Rates on Vegetable Growth and Nitrate Accumulation

Experiments were carried out on a vegetable field with Peking cabbage (Brassica pekinensis (Lour.)Rupr.), cabbage (Brassica chinensis var. Oleifera Makino and nemoto), green cabbage (Brassica chinensis L.), spinach (Spinacia oleracea L.) and rape (Brassica campestris L.) to study the effects of N forms and N rates on their growth and nitrate accumulation. The results indicated that application of ammonium chloride,ammonium nitrate, sodium nitrate and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach. Although no significant difference was found in the yields after application of the 4 N forms, nitrate N increased nitrate accumulation in vegetables much more than ammonium N. The vegetable yields were not increased continuously with N rate increase, and oversupply of N reduced the plant growth, leading to a yield decline. This trend was also true for nitrate concentrations in some vegetables and at some sampling times. However, as a whole, the nitrate concentrations in vegetables were positively correlated with N rates. Thus, addition of N fertilizer to soil was the major cause for increases in nitrate concentrations in vegetables. Nitrate concentrations were much higher in roots, stems and petioles than in blades at any N rate.

Distribution Characteristics and Accumulation Model for the Coal-formed Gas Generated from Permo-Carboniferous Coal Measures in Bohai Bay Basin, China: A Review

Coal-formed gas generated from the Permo-Carboniferous coal measures has become one of the most important targets for deep hydrocarbon exploration in the Bohai Bay Basin,offshore eastern China.However,the proven gas reserves from this source rock remain low to date,and the distribution characteristics and accumulation model for the coal-formed gas are not clear.Here we review the coal-formed gas deposits formed from the Permo-Carboniferous coal measures in the Bohai Bay Basin.The accumulations are scattered,and dominated by middle-small sized gas fields,of which the proven reserves ranging from 0.002 to 149.4×108 m3 with an average of 44.30×108 m3 and a mid-point of 8.16×108 m3.The commercially valuable gas fields are mainly found in the central and southern parts of the basin.Vertically,the coal-formed gas is accumulated at multiple stratigraphic levels from Paleogene to Archaeozoic,among which the Paleogene and PermoCarboniferous are the main reservoir strata.According to the transporting pathway,filling mechanism and the relationship between source rocks and reservoir,the coal-formed gas accumulation model can be defined into three types:"Upward migrated,fault transported gas"accumulation model,"Laterally migrated,sandbody transported gas"accumulation model,and"Downward migrated,sub-source,fracture transported gas"accumulation model.Source rock distribution,thermal evolution and hydrocarbon generation capacity are the fundamental controlling factors for the macro distribution and enrichment of the coal-formed gas.The fault activity and the configuration of fault and caprock control the vertical enrichment pattern.

A Study on the Ore-forming Effect of Mantle-derived Fluid

Based on summarizing of the effect of mantle-derived fluid on the formation of ores, especially on gold ore, and with the latest investigations, such as the formation of ore from the action of shallow-deep fluid, the transportation effect of the thermal energy by mantle-derived fluid, this paper mainly aims at the effect of mantle-derived fluid on the generation of hydrocarbons. With the proof from geochemistry and fluid inclusion, it was suggested that the mantle-derived fluid not only supplied source materials for hydrocarbons, but also supplied essential energy and matter necessary for the generation of hydrocarbons. The mantle-derived fluid had a good effect, but at the same time it had an adverse effect under specific conditions, on the formation of reservoirs. This paper also discusses the future direction and significance of studying mantle-derived fluid.

Orderliness of Hydrocarbon Accumulation Distribution in Rift Basins of Eastern China

The Cenozoic rift basins in eastern China show a clear temporal and spatial zonation and episodic tectonic evolution, which control their episodic hydrocarbon generation and zonal accumulation. In this paper, based on the study of depositional architecture, hydrocarbon migration system and dynamic evolution in the rift basins, combinations of hydrocarbon accumulation elements were analyzed using sequence stratigraphy. Hydrocarbon distribution in system tracts with different sequence orders was further studied. And we summarized stacking patterns and horizontal combination relationships for different types of reservoirs, such as lithological, tectonic-lithological, tectonic and stratigraphical reservoirs which can be observed from depression center to basin margin. The result reveals that various scales of pools exhibit significant distribution and evolution orderliness in different pool-forming units, i.e., depositional systems, plays and depressions. The regular distribution of various scales of pools is closely related to tectonic evolution and depositional filling in the rift basins. The result can be applied to the fine petroleum exploration in rift basins in eastern China. It will promote the scientific prediction and evaluation of reservoir types and their spatial distribution, lead to the active shifts of exploration targets in different zones, and thus support the stable progress of fine exploration in mature exploration areas.

氮素不同形态对早熟马铃薯产量和氮素积累的影响

以早熟马铃薯品种石薯1号为试验材料,通过田间小区试验,研究不同形态氮素(铵态氮、硝态氮、酰胺态氮)对早熟马铃薯干物质积累和氮素吸收动态的影响。结果表明:各处理马铃薯干物质积累符合Logistic生长曲线,铵态氮(NF1)、硝态氮(NF2)和酰胺态氮(NF3)处理成熟期干物质量分别为16401.6、15603.6和16383.0 kg·hm^(-2)。各处理马铃薯氮素累积速率均在现蕾期前显著上升,之后下降,进入成熟期后再次上升,并且NF3处理成熟期后氮累积速率显著高于其他处理,达5.53 kg·hm^(-2)·d^(-1)。成熟期氮素累积量NF3显著大于NF2和CK处理,与NF1处理差异不显著。NF3处理马铃薯氮素表观利用率显著高于NF1和NF2处理,为39.69%,且农学效率显著大于NF2处理,为52.67 kg·kg^(-1)。NF3处理商品薯产量显著大于其他处理,为56688 kg·hm^(-2);总产量为59460 kg·hm^(-2),显著大于不施氮对照和NF2处理。综合来看,在河北省二季作区马铃薯施用酰胺态氮能够显著促进马铃薯氮素吸收和利用,并提高商品薯产量,为本试验条件下的最优处理。

改性木屑和稻壳生物炭对土壤镉形态和水稻镉吸收的影响

【目的】农田镉(Cd)污染对人类健康构成严重威胁,探究不同改性生物炭对我国南方Cd污染农田中Cd形态变化及其在水稻中的富集特征的影响,为南方红壤性水稻土的安全利用和农业发展提供科学依据。【方法】以木屑和稻壳制成木屑生物炭(WCBC)和稻壳生物炭(RHBC),并用KOH和K_(2)SiO_(3)进行改性,共得4种改性生物炭,KOH改性的木屑生物炭(WCBC-KOH)和稻壳生物炭(RHBC-KOH),K_(2)SiO_(3)改性的木屑生物炭(WCBCK_(2)SiO_(3))和稻壳生物炭(RHBC-K_(2)SiO_(3))。通过盆栽试验,研究不同生物炭和添加量(0.25%、0.5%、1%)对红壤性水稻土的影响,包括化学性质(pH和有效硅)、Cd形态、水稻生物量、各组织的Cd富集和硅含量的影响。【结果】6种生物炭均能提高水稻土pH和有效硅含量,且随添加量的增加而增加。添加生物炭减少了土壤中可交换态Cd含量,同时增加了土壤中残渣态Cd含量,导致土壤中Cd的生物有效性和流动性显著降低,进而减少水稻对Cd的吸收。此外,添加生物炭还可以提高水稻地上部干物质重和产量,同时还显著增加了水稻地上部各组织的硅含量。相关分析表明,土壤pH和有效硅含量与可交换态Cd和水稻各组织Cd含量极显著负相关,且土壤pH降镉作用大于土壤有效硅的作用。【结论】6种生物炭均可使土壤中Cd向植物难利用形态转化,同时促进水稻生长和提高水稻产量,添加KOH和K_(2)SiO_(3)改性生物炭的效果要优于未改性生物炭。

柴达木盆地英雄岭构造带新生代隆升过程与油气成藏效应

英雄岭构造带是柴达木盆地内部最大的正向构造单元,构造带及周缘蕴育了丰富的油气资源。针对构造带地质结构认识不清、初始隆升时间认识不统一、形成过程和机制不明确等问题,通过构造解析、构造演化、构造模拟、埋藏史与生烃史恢复等手段,以钻井和连片三维地震数据为基础,以时间为主线,以构造活动期次为节点,以主干地震剖面为纲,以具体构造为目,从几何学和运动学方面揭示英雄岭构造带三维空间结构和形成过程。研究表明:英雄岭构造带空间上具有南北分带展布、东西分段相接、垂向上下分层叠置的特征;新生代以来构造带演化经历了古近纪断坳、新近纪早期初始隆升和新近纪晚期—第四纪调整定型3个阶段,演化过程具有自南向北、自西向东逐次扩展的特点,构造演化与油气成藏紧密相关;青藏高原隆升背景下特殊的盆地边界条件、内部结构和应力场变换可为英雄岭构造带成藏模式建立和下一步有利勘探方向选择提供参考。

隧道掏槽爆破岩块抛掷堆积形态的数值模拟

为了控制隧道掏槽爆破飞石范围,确保隧道爆破施工的高效性与安全性,利用离散元软件对掏槽体岩块抛掷堆积形态进行了数值模拟,结合某快速铁路单线隧道工程,研究了掏槽体岩块抛掷堆积形态及其主要参数。在对比分析掏槽体岩块堆积形态的模拟结果与实际测量结果的基础上,研究发现:掏槽体岩块的初速度为堆积形态的重要影响因素;在初速度为10 m/s的前提下,从爆破开始到岩体全部停止运动总共经历3.5 s,最终堆积形态近似于椭圆形;最大抛掷距离与前端堆积高度均符合工程实际测量结果。研究结果对隧道掏槽爆破设计和安全施工,具有重要的指导意义。

Mechanism of cross-level settlements and void accumulation of wide and conventional sleepers in railway ballast

The cross-level and twist irregularities are the most dangerous irregularity types that could cause wheel unloading with the risk of derailments and additional maintenance expenses.However,the mechanism of the irregularities initiation and development is unclear.The motivation of the present study was the previous experimental studies on the application of wide sleepers in the ballasted track.The long-term track geometry measurements with wide sleepers show an enormous reduction of the vertical longitudinal irregularities compared to the conventional track.However,wide sleepers had higher twist and cross-section level irregularities.The present paper aims to explain the phenomenon by discrete element method(DEM)modeling the development process of sleeper inhomogeneous support at cross-level depending on the sleeper form.The DEM simulations show that the maximal settlement intensity is up to 3.5 times lower for a wide sleeper in comparison with the conventional one.Nevertheless,the cross-level differential settlements are almost the same for both sleepers.The particle loading distribution after all loading cycles is concentrated on the smaller area,up to the half sleeper length,with fully unloaded zones under sleeper ends.Ballast flow limitation under the central part of the sleeper could improve the resilience of wide sleepers to the development of cross-level irregularities.The mechanism of initiation of the cross-level irregularity is proposed,which assumes the loss of sleeper support under sleeper ends.The further growth of inhomogeneous settlements along the sleeper is assumed as a result of the interaction of two processes:ballast flow due to dynamic impact during void closing and on the other side high pressure due to the concentration of the pressure under the middle part of the sleeper.The DEM simulation results support the assumption of the mechanism and agree with the experimental studies.

深层—超深层碎屑岩储层非均质性特征与油气成藏模式

深层—超深层地质条件下,储层的孔渗物性特征和流体动力连通关系决定了油气在储层中的流动状态,这也就决定了油气运移的动力条件和聚集成藏的机理与过程。本文基于对深层—超深层碎屑岩储层结构非均质性的研究,认识深层—超深层油气运聚成藏机制和过程,总结油气多期复合成藏模式,探索深层—超深层油气分布规律。碎屑岩储层普遍存在强烈的非均质性,受到沉积结构构造及成岩作用控制,表现出空间结构性特征,在埋藏至深层—超深层的过程中经历了差异性的成岩演化和油气充注。结构非均质性储层中的油气总体向上倾方向运移,受储层中砂体分布、隔夹层结构以及连通方式的影响,油气运移路径的分布极不均匀,在储层中任何部位都可能聚集,并可能继续运移到有利圈闭中富集。在深埋过程中,多期多幕的构造变动促使深层—超深层储层中已聚集的油气向着上倾方向运移调整,或沿着断裂向上运移调整至中—深层与之相关的有效储层中运移、聚集。深层—超深层勘探具有更为广泛的目标选择,洼陷区和斜坡区都可能成为有利勘探区域。现实的深层—超深层油气勘探新领域包括:构造高点油气藏向供源方向的拓展,深层—超深层烃源由断裂调整至中深层—超深层的次生油气聚集,深层—超深层与油气源相关的斜坡带以及深层—超深层生烃洼陷优质烃源岩层内部及相邻的有效储层。

塔里木盆地顺北地区东西部海相油气成藏差异

塔里木盆地顺北地区东西部海相油气成藏差异明显,自东向西油气主要表现为由富到贫,勘探风险明显加大。通过对满加尔坳陷西缘的顺北东部和阿瓦提坳陷东缘的顺北西部油气成藏的分析,对比海相油气成藏条件的差异性,明确二者成藏差异的原因。以顺北1、4、8号断裂带东北段为代表的顺北东部近年来不断获得高产,油气多期成藏,油气富集特征明显;但阿瓦提坳陷东缘的顺北西部钻探结果不理想,表现为以早期成藏为主,且油气成藏规模不大。顺北东西部存在烃源层分布条件、生烃演化史、烃源资源规模、成藏期及成藏模式等差异,主要表现为东部多源多期成藏和西部单源单期成藏。顺北东部紧邻满加尔生烃坳陷区,长期处于四源供烃条件,属于多源多期成藏;而顺北西部要么是本地的寒武系玉尔吐斯组烃源岩早期成藏,要么是阿瓦提坳陷奥陶系烃源岩晚期成藏,属于单源单期成藏。阿瓦提东缘英买力油田及近年来英西1井奥陶系的突破表明,阿瓦提海相油气以海西晚期成藏为主,喜马拉雅期成藏为辅。阿瓦提坳陷周缘烃源岩发育相对较差,海相油气藏分布局限,油气资源规模也有限。

钝化剂对镉污染温室黑土镉生物有效性及白菜生长的影响

为探究钝化剂对镉污染温室黑土镉生物有效性及白菜生长的影响,对镉中轻度污染的北方温室黑土施加炭基肥和菌糠生物炭,研究生物有效性及不同镉积累能力白菜的生长与镉吸收能力。结果表明,炭基肥和菌糠生物炭均可显著降低土壤中有效态镉含量(P<0.05),分别降低2.5%和1.72%,其中炭基肥效果更好。与不施加钝化剂组相比,在施加炭基肥和菌糠生物炭后,北辰和金峰生物量、株高和根长均显著增加(P<0.05),增量分别为37.7%、7.6%、35.2%和23.1%、5.2%、28.3%。两种白菜可食用部分对镉的积累显著降低(P<0.05);钝化剂对镉在植株体内迁移无显著影响。综合试验结果,在中轻度镉污染温室土壤环境中,炭基肥可促进白菜生长,有效降低土壤中有效态镉含量,同时显著降低高积累白菜北辰可食用部位镉含量,使其低于食品安全国家标准,实现安全生产。

贵州岩溶地区土壤-红托竹荪(Dictyophora rubrovalvata)系统Cd迁移累积特征及其影响因素研究

为探究岩溶区土壤-红托竹荪(Dictyophora rubrovalvata)系统中重金属Cd的迁移累积特征及其影响因素,采集了红托竹荪种植区土壤和红托竹荪样品,分析了土壤中Cd含量及其赋存形态、红托竹荪中Cd含量及富集特征,并采用主成分分析探讨了土壤中Cd迁移累积的影响因素。结果表明:红托竹荪种植区土壤总Cd含量为0.24~4.23 mg·kg^(-1),平均值为0.96 mg·kg^(-1),是GB 15618—2018《土壤环境质量农用地土壤风险管控标准(试行)》中农用地土壤污染风险筛选值的3.2倍,是贵州省土壤背景值的1.45倍。土壤Cd形态以可还原态为主,其含量占比为20.87%~63.81%,平均值为41.64%,Cd各形态占比为可还原态>残渣态>弱酸可溶态>可氧化态。红托竹荪中Cd含量为0.07~0.39 mg·kg^(-1)(以鲜样计),平均值为0.18 mg·kg^(-1),低于GB 2762—2017《食品安全国家标准食品中污染物限量》标准值(0.20 mg·kg^(-1))。富集系数和转运系数分别为0.50~21.91和0.31~8.89。红托竹荪种植区土壤pH值与弱酸可溶态Cd含量呈显著负相关(r=-0.435,P<0.05,n=26),与可还原态Cd含量(r=0.469,P<0.05)、土壤总Cd含量(r=0.392,P<0.05)呈显著正相关。红托竹荪中Cd含量(r=-0.670,P<0.01)、Cd的富集系数(r=-0.724,P<0.01)与土壤pH值呈极显著负相关关系。主成分分析表明,土壤pH值和K、Ca、Fe、Cu含量是红托竹荪富集Cd的主要影响因素。

考虑滑面材质的碎屑流试验堆积特征分析

为分析高速远程滑坡运动与堆积特征,在室内设置物理试验模型,设计级配、坡角、碎屑流质量、滑面材质4种因素,分析各因素对碎屑流堆积特征的影响。研究结果表明:坡角减小、滑面更粗糙使部分颗粒堆积或滞留于坡面,颗粒堆积特征与颗粒完全堆积于坡底时相比存在差异;滑面材质与冲程等堆积特征基本呈负相关,坡角与堆积特征基本呈正相关,二者对堆积特征影响最大;碎屑流质量与堆积特征基本呈负相关,对颗粒堆积特征分布影响较小;级配与颗粒堆积特征无明显相关性。

化肥减量配施有机肥对盐碱地土壤性状及镉形态的影响

盐碱地盐分含量高,会对植物生长起抑制作用或直接造成危害,盐碱地的安全利用对保障粮食安全具有重大意义。为探讨化肥减量配施不同有机肥对盐碱地土壤性状及镉形态的影响变化特征,试验在化肥施用减量20%的基础上,设厩肥30000 kg/hm^(2)(AM)、生物有机肥600 kg/hm^(2)(BF)、厩肥30000 kg/hm^(2)+生物有机肥600kg/hm^(2)(AM+BF)及化肥正常施用量(CK)4种施肥处理,研究不同有机肥配施对土壤性状、镉含量及形态的影响。结果表明:2020年,处理BF较CK土壤镉含量显著降低了16.99%;2021年,处理BF和AM与CK相比,土壤镉含量分别降低了14.06%和10.16%,且差异显著。2020年,与CK相比,处理BF、AM和AM+BF土壤有效态镉含量分别显著降低了67.44%、34.88%和60.47%;2021年,处理BF、AM和AM+BF与CK相比,有效态镉含量分别降低了66.67%、27.27%和51.52%,且差异显著。与CK相比,有机肥配施对土壤中镉形态的分配比例有明显影响,交换态镉降低19.34%~75.69%、有机结合态镉提高45.78%~135.22%、土壤pH提高1.06%~5.81%;阳离子交换量提高5.29%~29.11%、有机质含量提高4.35%~30.14%、土壤容重降低0.76%~9.09%、过氧化氢酶活性提高7.84%~56.02%、脲酶活性提高14.67%~29.07%、碱性磷酸酶活性提高16.54%~40.09%、微生物量碳提高8.02%~25.09%、微生物量氮提高12.28%~33.12%。综上,在盐碱土壤条件下,配施有机肥可改善土壤理化性状、生物学特性,促进土壤交换态镉向有机结合态镉的转化,达到降低土壤有效态镉的目的。

Cd在地肤[Kochia scoparia(L.)Schrad.]中的化学形态及亚细胞分布

为探究镉(Cd)在地肤[Kochia scoparia(L.)Schrad.]茎部与根系中的亚细胞分布特征,在不同pH和不同Cd浓度胁迫下,对成熟期地肤生物量及Cd在地肤根系、茎部的积累状况和化学形态特征进行研究。结果表明:所有处理地肤茎部生物量均高于根系,当Cd添加量为1.5~3.0 mg·kg^(-1)时,T处理(pH 6.1)地肤总生物量高于TS处理(pH 5.0);地肤将58.09%~89.35%的Cd积累在茎部,所有处理地肤Cd的富集系数大小为茎>根系,表明地肤茎对Cd的积累能力强于根系,且在Cd添加量为1.5~9.0 mg·kg^(-1)时,T处理地肤茎Cd积累量高于TS处理;地肤根系和茎中超过85%的Cd贮存在细胞壁与液泡中,表明二者是地肤细胞中Cd区室化分布和解毒的重要场所;地肤根系细胞器Cd所占比例低于地肤茎部,这也是地肤将更多的Cd富集在茎部的一个重要原因;地肤茎和根系中均以移动性和毒性相对较低的醋酸提取态、氯化钠提取态及乙醇提取态Cd分配比例最大(T为82.96%~88.17%;TS为83.70%~89.70%),其中醋酸提取态含量最高(T为37.31%~56.24%;TS为40.98%~52.32%),氯化钠提取态与乙醇提取态Cd含量接近,这种Cd赋存形式是地肤降低Cd生物有效性和减少Cd毒害的一种重要防御机制。当土壤pH为6.1和Cd添加量为1.5 mg·kg^(-1)时,地肤对土壤Cd的解毒较好。研究表明,地肤具有对不同Cd胁迫水平的耐性,且对酸性土壤有较强的适生性,因此适用于湖南地区酸性农田土壤的修复治理。

硝态铵态氮比例对不同氮效率烟草苗期氮素吸收及利用的影响

【目的】为明确最有利于烤烟和白肋烟氮素利用的氮素形态配比。【方法】采用盆栽的方法,以烤烟品种中烟100和白肋烟品种TN90为材料,设置5个硝态铵态氮比例(T1:NO_(3)^(-):NH_(4)^(+)=100:0;T2:NO_(3)^(-):NH_(4)^(+)=75:25;T3:NO_(3)^(-):NH_(4)^(+)=50:50;T4:NO_(3)^(-):NH_(4)^(+)=25:75;T5:NO_(3)^(-):NH_(4)^(+)=0:100),测定各处理的生物量、色素含量、硝酸还原酶(nitrate reductase,NR)和谷氨酰胺合成酶(glutamine synthetase,GS)活性、NH_(4)^(+)-N含量、硝酸盐含量、总氮含量、总糖和还原糖含量,比较不同硝态氮和铵态氮比例对烤烟和白肋烟两种不同氮效率烟草的生长、氮素积累及氮代谢的影响。【结果】(1)中烟100的NR和GS活性均在硝态铵态配比为75:25时最高;TN90的NR活性在硝态铵态配比为50:50时最高,GS活性在硝态铵态配比为25:75时最高。中烟100和TN90的总糖含量均在硝态铵态配比为50:50时最高,分别为8.22%和5.36%。(2)TN90和中烟100叶片中的硝酸盐含量均在硝态铵态配比为50:50时最低,分别为343.73 mg·g^(-1)和116.77 mg·g^(-1)。(3)基于主成分分析法对地上部干重、总色素含量、NR活性、GS活性、叶片总氮含量、叶片氮素积累量、总糖含量、还原糖含量、叶片硝酸盐含量倒数、叶片NH_(4)^(+)-N含量共计10个指标进行综合评价,烤烟在硝态铵态氮配比为75:25时得分最高,白肋烟在硝态铵态氮配比为50:50时得分最高。【结论】高硝态氮比例能有效促进烤烟的生长发育,适当增加铵态氮比例有利于促进白肋烟烟叶碳水化合物形成,从而提高烟叶氮代谢能力。综合生物量积累和主成分分析情况,烤烟和白肋烟分别在硝态铵态氮配比为75:25和50:50时综合表现较好。