洞庭湖湿地植被系统的碳贮量及其分配

利用生物量调查和实验数据.对洞庭湖湿地植被生态系统的碳密度、碳贮量及其分配进行研究.结果表明:乔木层植被碳密度为15.607～40.501 t/hm~2,草本层植被为5.906～21.632 t/hm~2.水生植物植被1.460～3.492 t/hm~2,平均14.954 t/hm~2比温带地区湿地植物碳密度高;未受干扰草甸土壤碳密度为260.510 t/hm~2,每年收获产品草甸是185.492 t/hm~2,林地234.513 t/hm~2,水生植物土壤为206.882 t/hm~2,低于全国湿地土壤平均值.碳贮量分配中.植被层、凋落物层和土壤层的碳贮量分别占各植被类型系统碳的总贮量的0.47%～14.69%,0.29%～1.10%和84.54%～99.53%.每年收获部分产品的草甸土壤碳密度只有未受人为干扰草甸的71.2%,原生草本植物草地改造成林地后,6年的时间,土壤的碳密度减少了10%.因此,控制人为干扰,防止湿地破碎化、保护好湿地、保证湿地的固碳潜力,是湿地管理中应该优先考虑的问题.     

黔中地区不同林龄杉木人工林碳贮量及其分配特征

在贵州中部开阳县选择不同林龄的杉木人工林,设置固定样地进行植被和土壤调查,分析黔中地区杉木人工林生态系统碳素的垂直空间结构、植被碳的层次分布与器官分配及杉木人工林碳贮量与林龄及林冠郁闭度等因子的关系。结果表明,杉木人工林生态系统碳贮量(t/hm2)表现为中龄林(140.08)近熟林(128.77)幼龄林(106.35),杉木人工林平均生态系统碳密度(t/hm2)为125.07,其垂直空间分布特征表现为土壤层(77.72)植被层(45.95)枯落物层(1.39),分别占生态系统碳贮量的62.14%,36.75%和1.11%,其中的植被碳贮量在乔木层、灌木层和草本层各层的分配比例分别为98.93%,0.83%和0.24%。杉木林各植被层碳贮量的器官分配表现为乔木层各器官的碳密度(t/hm2)大小依次为树干(15.10~24.66)树根(4.68~14.70)树叶(4.05~12.69)树枝(3.53~5.56),灌木层依次为枝干(0.10~0.47)根(0.07~0.19)叶(0.02~0.11),草本层地上部分(0.05~0.08)根(0.03~0.04)。杉木人工林碳贮量与林龄的关系表现为土壤碳贮量和生态系统碳贮量随林龄的增长呈先下降后升高的变化过程,植被碳贮量呈持续增加趋势。基于统计分析结果,植被碳贮量在林分郁闭度为0.65左右达到最高,生态系统碳贮量在0.8左右达到最大。     

太行山丘陵区群落演替进程中碳贮量变化特征

为了解植被演替过程中碳贮量分布格局,以太行山丘陵区典型群落为研究对象,采用样地调查法,对其生态系统碳贮量进行了研究.结果表明:(1)土壤碳密度随演替进程逐渐提高,其排序为:乔木阶段(58.3 t/hm2)＞灌丛阶段(43.1 t/hm2)＞草本阶段(20.47 t/hm2);(2)土壤活性有机碳含量随演替进程呈逐渐增高的趋势.其含量排序为:乔木阶段(0.94%)＞灌丛阶段(0.84%)＞草本阶段(0.34%);(3)在群落演替的过程中,植被碳贮量逐渐增加,栓皮栎群落最高,达40.30 t/hm2;草本群落阶段最低(1.34 t/hm2);灌木群落居中(8.26 t/hm2).在碳贮量构成中,乔、灌群落的乔木层碳贮量所占比重最高;草本层所占比例最小.草本层碳贮量所占比例随演替进程呈下降趋势.(4)生态系统碳总贮量随演替进程呈上升态势.由草本阶段的21.81 t/hm2,增加到灌木阶段的51.36 t/hm2,乔木群落阶段达到最大,为92.63 t/hm2.生态系统碳贮量增加约4.3倍.在碳贮量构成中,土壤碳储量所占比重最大.土壤碳贮量占总贮量的比重随演替进程呈下降趋势.     

湖南永顺闽楠人工林生态系统碳贮量及其分布特征

对湖南永顺43年生闽楠人工林生态系统生物量、碳贮量及其空间分布进行研究,采用平均标准木法和收获法对林分生物量及林下植被与枯落物生物量进行测定与估算,同时测定植物、土壤有机碳含量。结果表明:闽楠人工林林分生物量为295.65t/hm2,生物量分布表现为乔木层(96.70%)枯落物层(2.77%)灌木层(0.46%)草本层(0.07%)。闽楠各器官的碳素含量范围为440.83~506.01g/kg,排列顺序为树叶根茎粗根树枝细根树干树皮中根;闽楠韧皮部平均碳素含量低于外表皮,初生嫩叶碳素含量比多年生老叶高;灌木层植物的碳素平均含量为454.39g/kg,草本层植物为448.66g/kg,未分解枯落物为490.23g/kg,半分解枯落物为402.32g/kg;0-60cm土壤层有机碳含量平均值为16.53g/kg。闽楠人工林生态系统总碳贮量为288.98t/hm2,其中乔木层为133.98t/hm2(46.36%),灌木层为0.62t/hm2(0.45%),草本层为0.10t/hm2(0.07%),枯落物层为3.54t/hm2(2.56%),土壤层为150.74t/hm2(52.17%);闽楠各器官的碳贮量与其生物量成正比,树干的生物量最大,其碳贮量也最高,占乔木层碳贮量的59.33%。闽楠人工林乔木层年净生产力为11.25t/hm2,年净固碳量为5.44t/hm2,年净碳素累积量为3.12t/hm2,并且以地上部分为主。研究表明,在对区域尺度森林植被碳贮量估算时,取50%或45%作为通用标准,可能会导致估算结果偏低或偏高;闽楠人工林生态系统具有较高的碳汇能力,其系统碳贮量高于我国森林生态系统平均碳贮量(258.82t/hm2)。     

农牧交错带禁牧草地生态系统服务空间权衡与协同关系

为明确农牧交错带禁牧草地生态系统主要服务间的相互作用关系,以宁夏盐池县草地为研究对象,借助本地化的InVEST模型,对禁牧以来(2000-2015年)草地碳储存、水源涵养、土壤保持3项关键服务进行精准测度,明确其时空变化特征,以此为基础,通过逐像元相关系数法对3种服务间的权衡作用进行定量可视化表达,分析乡镇尺度各服务间的空间权衡与协同关系。结果表明:1)禁牧以来,草地生态系统碳储存、水源涵养和土壤保持功能显著增加,但增加过程存在一个显著的"N"型波动,碳储存总量及单位面积均值由217.46万t、5.78t/hm~2增加到263.12万t、6.19 t/hm~2;水源涵养总量及单位面积均值由2 884万t、76.69 t/hm~2增加到6 118万t、143.92 t/hm~2;土壤保持总量及单位面积均值由1 383万t、36.78 t/hm~2增加到3 474万t、81.71 t/hm~2。碳储存功能与草地覆被关系密切,年际波动小、增长稳定,水源涵养和土壤保持功能受降水和地形显著影响,年际波动大、空间差异显著。2)草地土壤保持与水源涵养功能呈显著的空间协同关系(面积占86.34%),碳储存与水源涵养功能关系复杂,空间权衡与协同关系不显著(面积分别占47.66%和52.34%),碳储存与土壤保持功能呈空间协同关系(面积占69.55%)。通过定量可视化评估草地生态系统各服务间的空间权衡与协同关系,可为草地生态系统优化提供科学依据,为草地资源管理提供参考。     

红壤丘陵区典型植被群落根系生物量及碳储量研究

采用标准地法和"WinRhizo根系分析系统"平面扫描,研究了红壤丘陵区六种典型植被群落的根系特征、生物量、固碳量及土壤碳储量.结果表明:(1)根系特征值随土壤深度增加呈递减趋势,马尾松、杉木混交林和马尾松、木荷混交林土壤表层根系分布密集,特征值较大,马尾松低效林根系分布稀疏,特征值最小;(2)不同植被群落,0-40 cm土层的根系生物量所占比例在58.89%～84.88%.0-20 cm土层的土壤碳储量所占比例在35.89%～48.67%;(3)该区乔木混交林的根系生物量大于纯林和火烧迹地,植被群落的灌草覆盖度是影响根系生物量的主要因素.马尾松、木荷混交林根系净生产力最大,为6.74 t/(hm~2·a),马尾松低效林最小,为1.28t/(hm~2·a);(4)马尾松、木荷混交林的根系固碳量和土壤碳储量最大,分别为60.66 t/hm~2和9086.32 t/hm~2,马尾松低效林最小,分别为15.97 t/hm~2和1 683.75 t/hm~2,根系固碳量只占土壤碳储量的极少部分,但根系通过改良土壤结构,对增强碳源汇集和贮存、积累碳素具有重要的影响.     

黄土高原子午岭森林碳储量与碳密度研究

基于样地林分调查与室内分析,运用清查平均生物量法和林木相对生长模型,研究了黄土高原子午岭林区3种森林碳储量及碳密度空间分布特征。结果表明:研究区森林生态系统植被含碳率变化范围为0.331 6～0.553 2 g/g;变异系数介于2%～14%,而枯落层含碳率为0.294 8～0.335 9 g/g;3种林地平均碳密度:柴松林为238.22 t/hm2,辽东栎林为235.75 t/hm2,油松林为191.58 t/hm2,柴松林及辽东栎林碳密度约是油松林的1.24倍;从研究空间尺度上土壤层植被层枯落层,其碳密度分别为105.21,88.11,28.53 t/hm2,其中植被层各分层碳密度大小差异显著,而土壤层碳密度随着土壤深度的增加而递减;3种森林生态系统有机碳库总储碳量为31.70 Tg,其中土壤层碳储量占整个碳库的49%,是植被层和枯落层碳储量的1.3倍和3.5倍,且碳储量空间分布呈现出:土壤层乔木层枯枝落叶层灌木层草本层。     

2013年河南省乔木林植被碳储量特征

准确评估区域范围内森林生态系统的固碳能力和趋势,系统分析不同森林类型的固碳能力时空异质性,对于实现森林可持续经营和固碳增汇具有重要意义。以河南省第八次森林资源清查数据为基础,运用生物量扩展因子法,研究了河南省乔木林植被的碳储量及碳密度特征。结果表明:2013年河南省乔木林植被碳储量7 422.78万t,其中栎类、杨树2个（组）树种植被碳储量占全省乔木林植被碳储量的67.32%。河南省乔木林植被平均碳密度为24.31 t/hm²,低于全国平均水平。河南省乔木林以幼、中龄林为主,其植被碳储量分别占全省乔木林植被碳储量的34.09%和40.84%。河南省天然林、人工林植被的碳储量相差不大,分别为3 512.35万t和3 910.43万t;平均碳密度分别为26.72 t/hm²,22.49 t/hm²。研究表明河南省乔木林植被,特别是人工林,未来固碳潜力巨大,将会在森林植被碳储量中占有越来越重要的地位。     

退耕还林地在植被恢复初期碳储量及分配格局研究

利用标准样方法研究了川西最主要的两种退耕还林植被(苦竹林和桦木林)在恢复初期生态系统碳储量、碳素密度以及空间分配特征.结果表明:(1)苦竹不同器官碳素密度为0.348 5～0.518 6 gC/g,桦木不同器官碳素密度为0.451 9～0.513 7 gC/g;(2)苦竹林林下枯落物的碳素密度为0.341 7 gC/g,桦木林林下枯落物的碳素密度为0.395 3 gC/g;(3)不同植物器官的碳储量分配与各器官的生物量显著相关.苦竹林分中竹秆生物量占48.87%,其碳储量占53.06%;桦木林树干生物量占57.25%,其碳储量占57.27%;(4)两种森林生态系统碳储量的空间分布格局表现为以土壤碳储量最大,占64.19%～82.59%,其次是乔木层,占21.93%～33.90%,最小是桔落物层,占0.27%～1.91%;(5)在退耕还林初期,植被恢复后土壤各层碳素密度小于对照的各层土壤碳素密度,土壤有机碳储量减少;(6)退耕地转变为森林后,成为大气CO2的一个重要碳汇.     

黄土丘陵区刺槐、辽东栎林碳氮密度及其分配特征

选取黄土丘陵区刺槐人工林和辽东栎天然次生林2个典型森林群落为研究对象,比较分析了各组分的有机碳和全氮含量与储量及分配特征。结果表明:刺槐和辽东栎林植被层的碳含量总体上呈现沿垂直方向的递减趋势,即乔木层灌木层草本层凋落物层;不同器官部位的碳含量呈现为:叶、干枝根,草本层地上部碳含量高于地下部。氮含量变化趋势不显著。辽东栎林生态系统碳密度为165.86t/hm~2,高于刺槐林生态系统(138.93t/hm2),而两者的氮密度差异不大。两生态系统碳氮密度的各部分排序为土壤乔木层凋落物层林下植被层,土壤层(0—100cm)的碳密度占生态系统碳库总量的51.1%~53.6%,而氮密度占71.4%~84.4%,表明控制水土流失对维持研究区的生态环境及土壤固碳潜力至关重要。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.