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1.
为了研究不同磷肥水平下酸性红壤上玉米不同部位丛枝菌根真菌(Arbuscular mycorrhizal fungi, AMF)群落多样性和组成结构,明确玉米不同部位AMF群落的分布特征及对磷肥的响应差别,为提高酸性红壤磷素利用提供理论依据。本实验设置三个磷肥水平：不施磷、低磷(25 mg P /kg)和高磷(100 mg P /kg),玉米培养4周后,测定玉米生物量和土壤理化性质,利用高通量测序技术检测玉米根部、根际和非根际土壤AMF群落结构和多样性。结果显示,随着磷肥水平增加,玉米生物量显著提高,高磷处理下玉米地上部磷含量显著高于不施磷和低磷处理。取样部位(根部、根际和非根际)显著影响了AMF群落优势属球囊霉属(Glomus)、巨孢囊霉属(Paraglomus)和近明球囊霉属(Claroideoglomus)相对丰度,但是磷肥影响不显著。类似的,取样部位而不是磷肥显著影响了AMF群落香农指数和物种丰富度。非度量多维标度(NMDS)结果显示,根部样品与非根际和根际土壤样品群落距离更远,而相同取样部位中不同磷肥水平间群落组成更为相似；置换多元方差分析(PERMANOVA)进一步表明,取样部位而不是磷肥显著影响了AMF群落组成结构,主要表现在根部样品与根际和非根际土壤不同。因此,酸性红壤上玉米不同部位对AMF群落的影响明显高于磷肥作用,表明AMF应用于酸性红壤时应重点考虑作物部位的特性。 相似文献
2.
为了研究土地利用方式对酸性红壤丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)群落的影响，调查了酸性红壤4种土地利用方式 (草地、玉米、花生和大豆) 下非根际和根际土壤AMF群落多样性和组成结构。结果表明：土地利用方式显著影响了AMF群落优势属球囊霉属(Glomus)和巨孢囊霉属(Paraglomus)的相对丰度，但是根际作用影响不明显。土地利用方式而非根际作用显著影响了AMF群落香农指数和物种丰富度，其中大豆地表现出最低的香农指数和物种丰富度。土地利用方式和根际作用都显著影响AMF群落组成结构，但是土地利用方式的作用强度明显高于根际作用。球囊霉属主要解释了不同土地利用方式之间的AMF群落组成差异。土壤pH是影响土壤AMF群落结构的最关键因子。因此，土地利用方式比根际作用表现出对酸性红壤AMF群落更大的影响，展现了土地利用变化在影响土壤AMF群落方面的重要作用。 相似文献
3.
不同秸秆还田方式对旱地红壤细菌多样性及群落结构的影响 总被引：3，自引：0，他引：3
为明确不同秸秆还田方式下土壤细菌群落结构变化特征，以南方典型旱地红壤为研究对象，基于中国科学院鹰潭红壤生态实验站玉米单作系统不同秸秆还田方式的长期试验，利用高通量测序明确了不同秸秆还田方式对土壤细菌多样性及群落结构的影响。结果表明：1）秸秆还田对土壤肥力提升显著，以秸秆猪粪配施（NPKSM）提升效果最佳；2）常规化肥处理（NPK）对细菌多样性无显著影响，但秸秆还田（NPKS）、秸秆猪粪配施（NPKSM）以及生物质炭（NPKB）处理均显著提升土壤细菌多样性；3）速效磷（AP）和土壤有机碳（SOC）变化是影响细菌多样性指数的主要因素，而速效钾（AK）、pH、总磷（TP）以及总氮（TN）均显著驱动细菌群落结构变异。研究结果从培育红壤肥力与微生物多样性的角度，为农业生态系统生物功能和土壤健康的协同提升提供了科学依据。 相似文献
4.
利用丛枝菌根真菌（Arbuscular mycorrhizal fungi，AMF）从农田生态系统获取养分，是红壤作物吸收土壤磷（P）素的有效途径。针对我国南方红壤生物功能退化、P素生物有效性低、作物产量低等问题，如何调控作物根际AMF群落，优化其与宿主的互惠共生关系，是打破红壤区作物P摄取瓶颈的关键。本研究结合红壤旱地生态间作与有机（秸秆、猪粪、生物肥）无机肥料配施的4种多样化培肥措施，基于作物产量和红壤磷素活化水平，筛选最优培肥模式。进一步利用扩增子高通量测序和显微观察等技术，解析红壤旱地最优培肥措施调控AMF群落组成，揭示优化的AMF群落激发宿主玉米P素摄取机理。结果表明，花生/玉米间作结合秸秆/生物肥的有机无机配施（In+NPKSB）相较于其他培肥方式使红壤旱地全磷（TP）提高29.07%、有效磷（AP）提升1.35倍，且增强了玉米根内AMF群落科水平间的联系。该措施AMF定殖率是传统培肥措施的2.24倍，提高玉米根际酸/碱性磷酸酶（ACP/ALP）活性32.18%和41.66%，玉米生物量提高34.98%，产量提高67.27%。本研究证实红壤旱地花生/玉米生态间作结合秸秆/生物肥有机无机配施的培肥措施可通过优化玉米根内AMF群落组成，促进土壤P素活化，为在红壤旱地因地制宜推广可持续农业发展的集成应用提供理论依据。 相似文献
5.
沙坡头地区地衣和藓类结皮丛枝菌根真菌多样性研究 总被引：1，自引：1，他引：0
丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)是自然界分布最广的一类植物共生真菌,可与生物土壤结皮(Biological soil crust,BSC)的隐花植物形成共生体,对荒漠植被的恢复和演替具有重要意义。目前针对不同类型BSC的AMF群落结构及其多样性研究较少,限制了AMF群落对BSC发育的作用和对荒漠生态系统贡献的理解。利用高通量测序技术,对腾格里沙漠东南缘沙坡头固沙植被区地衣和藓类结皮及其下层土壤AMF群落组成与多样性进行研究,分析不同结皮类型AMF群落结构的差异。结果发现,AMF群落丰富度和多样性表现为:藓类结皮下层土壤地衣结皮下层土壤藓类结皮地衣结皮。地衣和藓类结皮及其下层土壤AMF均属于球囊菌门、球囊菌纲,以球囊霉属、类球囊霉属、盾巨孢囊霉属、巨孢囊霉属和一种未分类属为优势,且地衣和藓类结皮AMF群落在属水平差异显著。主成分分析结果显示,藓类结皮下层土壤中AMF群落物种组成与其他各组有显著差异,表明随着结皮的发育,AMF群落多样性增加,结皮演替与AMF群落多样性之间具有相互促进的作用。 相似文献
6.
为揭示典型潮土微生物群落及其生态网络对秸秆还田的响应机制,选择长期小麦-玉米轮作下不同秸秆还田处理的试验地为对象,应用高通量测序和生态网络等方法,阐明秸秆掩埋配施不同氮肥后土壤细菌群落组成、细菌网络共存关系以及与土壤养分的关联。结果表明：（1）与秸秆移除且不施氮肥处理相比,秸秆还田配合常规施肥处理显著降低土壤pH,提高了土壤全氮、有机碳、有效磷、速效钾和硝态氮含量（P < 0.05）。秸秆掩埋配施氮肥有利于增加土壤养分含量。（2）不同秸秆还田方式和氮肥施用量处理的细菌Alpha多样性无显著差异,而细菌群落结构差异显著。pH、SOC和TN等因子驱动了细菌群落结构变异。酸杆菌门、变形菌门、拟杆菌门和绿弯菌门是潮土细菌群落的主要优势菌门。（3）共现网络分析得到4个主要的生态集群,均与土壤养分有显著相关性。模块1中物种丰度与SOC、TN、TP、NO3- -N、AP和AK呈极显著负相关（P < 0.001）,与pH呈极显著正相关（P < 0.001）;模块2和模块3中物种丰度与大部分养分含量呈正相关,与pH呈负相关。因此秸秆还田配施氮肥可以通过调节细菌互作关系,从而调控土壤肥力。研究结果可为秸秆的资源化利用和土壤施肥管理提供科学依据。 相似文献
7.
《农业研究与应用》2021,34(4)
土壤微生物是土壤—作物系统养分循环的重要驱动力,其中丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)能够促进作物对养分的吸收。木薯是我国南方重要的经济作物,是多种行业的重要原材料。为揭示不同土壤质地木薯根域土壤AMF群落结构特征,解析土壤因子对AMF类群的影响。以木薯品种华南205 (SC205)为材料,通过田间根袋培养,利用高通量测序平台进行真菌扩增子测序,分析不同处理木薯根域AMF类群组成和多样性差异。结果表明,木薯根域土壤AMF主要为球囊霉属(Glomus)、无梗囊霉属(Acaulospora)、盾巨孢囊霉属(Scutellospora)、类球囊霉属(Paraglomus)和双型囊霉属(Ambispora)。优势属为球囊霉属和无梗囊霉属。两种土质各处理AMF属水平上无显著差异,种水平分布受土壤质地及根袋的影响,粘土AMF多样性(Simpson指数)高于砂质壤土。两种土质中都发现独有种,土壤质地对木薯根域AMF群落分布有一定的影响。RDA分析表明Glomus与速效磷、速效氮、铵态氮正相关;Acaulospora与速效磷,速效氮弱负相关;Scutellospora与所有速效养分负相关;Paraglomus与所有速效养分表现出正相关;Ambispora与大部分速效养分表现出负相关。木薯根域AMF资源丰富,不同土壤质地条件下的AMF群落组成和丰度存在差异,土壤速效养分与AMF群落结构差异密切相关。该研究为进一步探索AMF在木薯上的应用提供理论参考。 相似文献
8.
秸秆还田方式对根际固氮菌群落及花生产量的影响 总被引：1，自引：0，他引：1
9.
丛枝菌根真菌（AMF）在土壤与植物的磷素循环中发挥着关键的作用。采用盆栽实验研究了丛枝菌根真菌群落对白三叶草植株生物量、磷吸收和土壤磷酸单酯酶活性的影响。结果表明,接种不同AMF群落均能显著地促进白三叶草植株的生长及其对磷素的吸收,提高根际土壤磷酸单酯酶的活性。Mnp处理中,白三叶草生物量最大,白三叶草总生物量、茎叶生物量和根系生物量分别比对照处理（-M）提高64.48%、61.48%和84.91%。不同菌根处理中,Mck处理显著地提高白三叶草磷吸收和土壤磷酸单酯酶活性,白三叶草磷吸收总量和茎叶磷吸收量分别比对照（-M）提高107.18%和91.91%,土壤碱性磷酸单酯酶和酸性磷酸单酯酶活性相对对照（-M）分别提高54.33%和138.43%。碱性磷酸单酯酶活性与AMF群落中的Acaullospora属孢子数呈显著的正相关关系,而酸性磷酸单酯酶活性则主要受Paraglomus属孢子数的影响。说明接种AMF群落可显著地影响土壤的磷酸单酯酶活性,从而影响白三叶草的生长及其对磷素的吸收。 相似文献
10.
秸秆与化肥和鸡粪配施改变了土壤微生物群落结构及微生物间的相互作用关系,但这种变化与小麦产量间的关系尚不清楚。本研究依托7年长期定位试验,选取5个施肥处理：不施化肥+秸秆离田（N0S0）、不施化肥+秸秆还田（N0S）、常规施化肥+秸秆离田（NS0）、常规施化肥+秸秆还田（NS）和施化肥+秸秆还田+鸡粪替代20%氮肥（NSM）,研究了不同施肥方式对细菌-真菌共现网络中微生物组成的影响,以及关键微生物与小麦产量间的相关关系。结果表明,与N0S0处理相比,NS0、NS和NSM处理的小麦籽粒产量分别提升539.20%、611.56%和676.56%,而N0S处理无显著变化。细菌和真菌群落组成均可分成显著不同的3组,分别为N0S0+N0S、NS0以及NS+NSM,即微生物群落组成在是否施用化肥之间显著不同;相同施用化肥情况下,在是否有施用有机物料之间显著不同。将重要性从高到低排序,有效磷（AP）、电导率（EC）、微生物生物量氮（MBN）、土壤有机碳（SOC）、易氧化有机碳（ROC）和颗粒有机碳（POC）是导致不同处理细菌群落结构变化的主要土壤理化性质,EC、MBN、ROC、POC、AP和SOC是导致不同处理真菌群落结构变化的主要土壤理化性质。细菌-真菌共现网络中,两个关键模块（模块1和模块4）与小麦产量变化显著相关。NS+NSM处理提升了模块4中与小麦产量正相关的类诺卡氏菌属（Nocardioides）、纤维单胞菌属（Cellulomonas）、Pir4_lineage、金孢子菌属（Chrysosporium）、无茎真菌属（Acaulium）和裂壳菌属（Schizothecium）等有益菌的相对丰度,它们可降解纤维素和木质素、促进养分转化和循环或抑制病原菌生长;并显著降低了模块1中与小麦产量负相关的葡萄穗霉属（Stachybotrys）、无色穗孢属（Achroiostachys）和Fusicolla的相对丰度,它们为不利于土壤健康和作物生长的植物病原真菌。因此,化肥配施秸秆及化肥配施秸秆和鸡粪利于关键有益微生物增加及病原真菌减少,关键微生物的功能和相对丰度对小麦产量具有影响。 相似文献
11.
低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响 总被引：2，自引：2，他引：0
【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。 相似文献
12.
Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
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. 相似文献
13.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
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. 相似文献
14.
Thomas Larsen Jesper Luxhøi Jakob Magid Lars Stoumann Jensen Paul Henning Krogh 《Biology and Fertility of Soils》2007,44(1):59-68
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. 相似文献
15.
《中国生态农业学报》2014,(6)
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, 相似文献
16.
《中国生态农业学报》2014,(7)
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, 相似文献
17.
《中国生态农业学报》2014,(8)
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, 相似文献
18.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
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. 相似文献
19.
I.L. Boyd 《Biological conservation》2010,143(7):1664-1674
“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. 相似文献
20.
Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage 总被引：1，自引：0，他引：1
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. 相似文献