广西东融发展片区碳排放时空特征及其驱动因素

[目的] 揭示县域碳排放的时空格局演变及其驱动因素,为区域规划战略的实际应用和实现“双碳”目标提供科学依据。[方法] 基于广西壮族自治区东融发展片区2005,2010,2015,2020年碳排放数据,运用空间自相关分析测算各区域之间的碳排放时空异质性特征,并在构建指标体系的基础上,运用地理探测器计算碳排放时空演变的驱动因子。[结果] ①广西东融片区各县区碳排放量在空间上存在异质性。2005—2020年,该区碳排放量在空间上呈现“西南高,东北低”,经济发达的区县碳排放量增速快;②各区县碳排放量在总体上呈现稳步上涨的趋势。不同经济发展水平的区县间碳排放量差距逐渐拉大;③在碳排放时空分异驱动力分析方面,能源消费结构和城市经济密度的影响最强。[结论] 广西东融发展片区碳排放时空特征与人类活动密切相关,达成“双碳”目标必须以规范碳排放行为为前提。     

基于“三生”空间的重庆市土地利用演变与城镇化关系研究

[目的] 分析重庆市土地利用时空演变规律,探究土地利用转型及景观格局响应的演变特征与城镇化的关系,为重庆市"三生"土地规划与城镇化可持续发展提供数据支持。[方法] 基于"三生空间"功能分类的视角构建用地分类标准,利用2000,2010,2020年土地遥感影像和夜间灯光数据,采用转移矩阵、相关性分析及回归分析法进行分析。[结果] ①2000-2020年重庆市生产、生态空间总体减少,生活空间持续扩张。2000-2010年,生产、生态空间减少191.87,252.95 km²,生活空间增大446.03 km²;2010-2020年,生产空间面积减少13.76 km²,生态空间减少324.05 km²,生活空间增大314.87 km²。②重庆市生产功能向生活功能转化较为明显。随着城镇化加强,生态空间转向生产空间显著,功能转变明显聚集于重庆市中心区域。③重庆市空间景观破碎度减小,景观复杂度逐渐提高,林草水生态空间占据主导优势。④2000-2010,2010-2020年土地利用面积变化对夜间灯光值的影响存在差异;2000年,城镇生活空间、农村生活空间变化对夜间灯光变化影响起主导作用,而2020年工业生产空间、城镇生活空间变化对夜间灯光变化影响较强。[结论] 重庆市各类空间发生相互转换,利用不同"三生"空间类型变化和城镇化的关系,推动土地规划与城镇化协调发展。     

基于土地利用变化的陕西省县域碳排放时空变化及影响因素研究

[目的] 分析2000—2020年陕西省县域碳排放时空变化和影响因素,为陕西省生态文明建设和实现低碳可持续发展提供参考。[方法] 利用社会经济数据和土地利用数据,构建碳排放估算模型,核算了2000—2020年陕西省县域碳排放总量,分析了陕西省碳排放时空分布格局与演化特征,并通过地理加权回归(GWR)模型探究了碳排放的影响因素。[结果] ①总量上,2000—2020年陕西省碳排放量总量呈上升趋势,从2000年的3.30×10⁷ t增长至2020年的1.93×10⁸ t,历经“大幅增长—缓慢增长”两个阶段。②空间上,2000—2020年陕西省碳排放量中心逐步向东北方向移动,空间分布范围呈现扩张态势,热点区主要分布在榆林市北部县域、西安市和咸阳市辖区的周边部分县域,冷点区主要分布在佛坪县和石泉县。③影响因素上,人均GDP值、土地利用程度和人均社会零售总额与陕西省各县域碳排放量呈正相关,产业结构与陕西省60.74%县域碳排放量呈负相关,人口密度与陕西省92.52%县域碳排放量呈负相关。[结论] 建议通过制定差异性区域碳减排方案,优化土地利用结构,控制建设用地增长规模,提高公众低碳环保意识等方式促进陕西省县域低碳发展。     

河南省"三生"功能时空演变特征及影响因素

随着城镇化进程快速推进，国土空间功能格局产生剧烈演变，探讨国土空间"三生"功能的时空演化特征及影响因素，可为区域协调可持续发展和国土空间优化布局提供科学依据。该研究以河南省县域单元为例，从生产、生活、生态三个维度构建指标体系，评价区域2000、2006、2012年及2018年"三生"功能的空间格局特征及演化规律，并利用主成分分析法诊断"三生"功能演变的影响因素及作用机制。结果表明：1）2000-2018年河南省各县域"三生"功能均呈现不同程度的增长态势，空间上"三生"功能存在地域分异特征，生产功能空间梯度差异显著，生活功能由市辖区向外逐渐减弱，生态功能呈现"山地丘陵区>平原区>市辖区"的梯度变化；2）2000-2018年河南省"三生"功能发展变化明显，24.39%的县域生产功能明显减弱，86.99%的县域生活功能水平得到提升，而生态功能平稳发展，减弱区域较少；3）粮食保障、社会保障、生态维持是影响河南省"三生"功能演变的重要因素，经济发展与生态承载是基础性影响因素，说明不同影响因子间形成共同推力才能促进"三生"功能的良性发展。研究结果可为促进国土空间规划及空间可持续利用提供参考与依据。     

山西省2005-2018年“三生”功能的时空分异特征及其影响因素

[目的] 探究山西省不同县域“三生”功能时空动态演化特征并分析其影响因素,为国土空间规划提供依据。[方法] 基于山西省107个县2005,2010,2018年土地利用类型和统计数据,采用综合指数模型、动态度和空间计量模型分析其“三生”功能时空演化过程及影响因素。[结果] ①2005—2018年山西省“三生”功能空间分异明显,生产、生活功能格局特征趋同,呈现出“平原高,山区低”的分布格局;生态功能分布特征与生产生活相反,空间格局稳定;“三生”综合功能提升明显,表现为“南高北低,中部高东西低”的局面。②2005—2018年生产和生态功能水平缓慢变化,呈现出先上升后下降波动变化趋势;生活功能处于快速提升阶段,提升明显;“三生”综合功能持续提高,但提升缓慢。“三生”功能协调性提高,但功能单一化程度较高。③“三生”功能时空分异是自然地理环境、自然资源禀赋及社会经济因素综合作用的结果,“三生”功能受制于自然地理条件,自然资源禀赋是“三生”功能的基础和保障,社会经济因素则是“三生”功能的主要驱动力。[结论] 山西省各县域需要在自然地理条件约束和经济社会转型发展背景下,促进“三生”功能各自提升与彼此协调,需要在明确各自主体功能定位的基础上,因地制宜,合理发展,依托自身区域优势与资源禀赋,构建起利益联结机制,推动山西省整体协调可持续发展。     

2009-2018年广西国土空间“三生”功能评价及耦合协调性分析

[目的]探究广西壮族自治区国土空间“三生”功能之间的协调关系,为区域的协调发展调控提供科学依据。[方法]采用多因素综合评价法评价2009-2018年广西“三生”功能利用程度,并应用耦合协调模型,分析三者之间的变化特征及耦合协调关系。[结果]①2009-2018年广西“三生”功能得分整体呈上升趋势,其中生活功能变化最大且各地级市上升幅度不尽相同。②广西国土空间“三生”功能耦合性指数缓慢增长,协调发展度分值分布不均,各地级市协调等级上升跨度不同。③广西国土空间“三生”功能耦合协调性空间分布呈西部地区大于东部地区,沿海地区大于内陆地区。[结论]广西国土空间“三生”功能均有较大提升,各地级市发展速度不尽相同;空间分异呈“东北、西南高,西北、东南低”的特征,生产功能和生活功能存在一定联系;广西国土空间“三生”功能良性互动越来越强,空间分异明显呈西部向东部地区逐渐升高特征,各地级市之间发展不均衡现象显著。     

1990—2020年河南省黄淮海平原国土空间“三生”功能时空演变

[目的] 对国土空间“三生”功能时空演变进行研究,为区域国土空间新格局的构建,实施监督国土空间规划和促进区域协调发展提供科学依据。[方法] 以河南省黄淮海平原为研究区,基于1990,2005和2020年土地利用遥感监测数据,运用功能归并、地理网格采样和空间协调度等方法开展研究。[结果] 1990—2020年,生产、生活功能指数分别上升了1.30%和20.83%,且均呈西部低而中东部高的特点,生态功能指数下降了2.52%。生产功能指数以相对平衡状态为主,生活功能变化幅度较小,空间上呈零散分布特点,生态功能空间变化幅度强烈。缩小区多位于研究区西南部,扩张区集中于西部和东端。国土功能的协调度逐渐变差,中高、高协调类型区面积均偏小,低协调类型区扩张显著,并成为最主要的功能协调类型,中低和中协调类型区面积比例持续下降。[结论] 应依据研究区国土空间的功能服务特性,合理统筹部署国土空间开发及利用,促进国土空间的生产、生活与生态功能协调发展。     

长江中下游典型区域土地利用碳排放风险——以江西省九江市为例

[目的]定量测算江西省九江市土地利用碳排放,揭示其时空演变特征,并估算土地利用碳排放风险,为九江市构建绿色低碳土地利用方式提供科学参考。[方法]采用土地利用碳排放系数法测度2000—2020年九江市土地利用碳排放和时空变化规律,并从网格化的视角,利用碳排放风险指数识别各县区碳排放风险,基于对数平均迪式指数(LMDI)模型,分析土地利用碳排放的影响因素。[结果] 2000—2020年九江市土地利用净碳排放量呈递增趋势,年均增幅为13.75%,建设用地是主要碳源,占碳排放量的90%以上,林地是主要碳汇。九江市净碳排放量呈现“东北高,西南低”的空间分布特征,森林覆盖率好的武宁县、修水县一直处于碳汇功能,濂溪区、浔阳区、湖口县、瑞昌市的碳排放量占九江市净碳排放量的95%以上。九江市土地利用碳排放风险整体偏低,并呈现“东北高,西南低”的分布特征,长江沿岸县区濂溪区、浔阳区和柴桑区处于高度碳排放风险区。经济发展水平是碳排放增加的主要因素,能源消费强度则是抑制碳排放的关键因素。[结论] 2000—2020年九江市土地利用碳排放大幅增加,应控制新增碳源用地,优化土地利用结构,并积极探索低碳绿色能源利用...     

云南省土地利用碳排放时空演变特征及影响因素

[目的] 研究云南省土地利用碳排放的时空变化规律及其影响因素,为云南省优化土地利用结构,实现低碳发展目标提供理论依据。[方法] 基于云南省2005,2010,2015,2020年4期土地利用和化石能源消费数据,对全省碳排放效应进行测算,运用空间可视化和空间自相关研究云南省2005—2020年的碳排放时空变化规律和空间集聚特征,利用地理探测器对其影响因素进行分析。[结果] ①2005—2020年云南省建设用地增幅最大,动态变化度达7.90%。②区域净碳排放快速增加,年增长6.5%;碳排放空间特征为“中间高、四周低”;碳足迹在研究期内增长明显,碳生态承载力较为稳定,导致碳生态赤字日益升高。③人口规模、经济水平、产业结构、土地利用等促进了云南省各地州市碳排放的增加。[结论] 应保护或合理增加云南省林地等碳汇地类的面积并加强其动态监测;控制建设用地面积和能源消费总量;探索碳补偿机制并发挥碳汇地区的辐射效应。     

福建省土地利用变化碳排放时空差异与碳补偿

[目的] 开展土地利用碳排放差异与碳补偿研究，为各地域根据净碳排放量制定低碳发展政策提供依据。[方法] 基于2005—2020年福建省土地利用和能源消费数据，构建碳排放以及碳补偿价值测算模型，计算各市域不同时段的碳排放量以及碳补偿价值。[结果] ①福建省土地利用变化净碳排放呈现出明显的增长趋势，增长速度先快后慢。建设用地为主要碳源，其碳排放量增加3.41×10⁷ t；林地为主要碳汇，其碳吸收量减少近3.00×10⁴ t。②净碳排放量高值区域主要分布在碳排放量高、碳补偿率低的福州市、泉州市和漳州市，净碳排放量低值区域主要分布在碳排放量少、碳补偿率高的南平市，除厦门市外，各市的净碳排放强度与净碳排放量的空间分布相似。③碳补偿价值与各市净碳排放量的空间分布具有高度相似性，高碳补偿区主要是经济发展水平高、净碳排放量大的福州市、泉州市，受偿区主要是经济发展水平低、净碳排放量小的南平市。[结论] 为实现区域协调以及低碳发展，需不断完善碳补偿机制，从低碳层面依靠碳补偿推动区域低碳协调发展。     

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.