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1.
近地层臭氧浓度增高对稻米品质的影响: FACE研究 总被引：1，自引：0，他引：1
利用稻田开放式空气中臭氧浓度增加(FACE,Free Air gas Concentration Enrichment)平台,以常规粳稻‘武粳15’和杂交粳稻‘陵风优18’为供试材料,设置大气背景臭氧浓度(Ambient)和高臭氧浓度(比Ambient增高21%,模拟21世纪中叶臭氧浓度)两个水平,研究臭氧胁迫对大田生长水稻成熟期稻米加工、外观、蒸煮/食味和营养品质的影响及其种间差异。结果表明,近地层臭氧浓度增高使稻米糙米率、精米率和整精米率均不同程度下降,其中精米率降幅达显著水平。与Ambient相比,臭氧胁迫使两品种稻米垩白米率、垩白大小和垩白度平均分别增加15.0%(P=0.10)、42.0%(P0.05)和60.5%(P0.05)。臭氧胁迫使稻米胶稠度平均降低7.1%(P0.05),但对两品种稻米直链淀粉和糊化温度均无显著影响。稻米RVA谱测定结果显示,臭氧胁迫对稻米最高黏度值、崩解值、冷胶黏度值、消减值和回复值均无显著影响。臭氧胁迫使两品种稻米蛋白质浓度呈增加趋势,但均未达显著水平。方差分析表明,多数情况下,两品种间稻米诸品质性状存在显著差异,但品种与臭氧的互作对所有测定指标均无显著影响,说明两品种稻米品质对臭氧胁迫的响应无明显差异。本试验在开放稻田条件下运行,适度臭氧胁迫使稻米垩白明显增加,胶稠度显著下降,但对其他米质指标影响较小,两品种趋势一致。 相似文献
2.
利用环境生长室探讨不同CO2浓度和土壤水分亏缺处理下玉米植株生物量、气孔形态与分布特征、叶片气体交换参数、叶绿素荧光参数等生长及生理指标的变化规律。以‘郑单958’ 玉米品种为试材,利用环境生长室设置2个CO2浓度和4个土壤水分梯度对玉米进行CO2浓度和水分处理。结果表明：1）不同程度土壤水分亏缺均显著降低玉米地上生物量（P<0.05）,但CO2浓度升高增加了轻度水分亏缺条件下玉米地上生物量（P<0.01）和总生物量（P<0.01）。2）大气CO2浓度升高导致轻度和中度水分亏缺条件下玉米的净光合速率（Pn）分别提高15.8%（P<0.05）和25.7%（P=0.001）,而CO2浓度升高却降低了玉米叶片蒸腾速率（P<0.001）和气孔导度（P<0.001）,最终导致玉米瞬时水分利用效率均显著提高（P<0.001）。3）不同水分处理对玉米叶片气孔密度和单个气孔形态特征均造成显著影响（P<0.01）。因此,大气CO2浓度升高可以增加轻度水分亏缺条件下玉米叶片氮含量、叶片非结构性碳水化合物含量和光合电子传递速率,从而提高玉米植株的生物量累积以及叶片碳同化能力和水分利用效率。研究结果将为深入理解气候变化背景下玉米对大气CO2浓度升高和土壤水分亏缺的生理生态响应机制提供科学依据。 相似文献
3.
为探讨磁化水灌溉处理在促进植物生长、提高植株重金属耐受性方面的作用机制,本研究采用随机区组试验设计,研究了镉胁迫（0 μmol·L-1、50 μmol·L-1、100 μmol·L-1）下磁化水灌溉处理对1 a生欧美杨''I-107''光合特性、叶绿素荧光动力学参数及生长特性的影响。结果表明：1）镉胁迫会显著降低植株高生长和根茎叶干物质量;低浓度（50 μmol·L-1）镉处理促进根系直径及体积增大（P<0.05）,高浓度（100 μmol·L-1）则会抑制根系各形态参数;镉胁迫下欧美杨叶绿素b和类胡萝卜素含量分别降低12.50%、43.24%和19.27%、46.37%（P<0.05）,净光合速率（Pn）、蒸腾速率（Tr）、胞间二氧化碳（Ci）分别降低13.68%和33.68%、8.07%和27.81%、5.00%和14.99%（P<0.05）,同时,PSⅡ潜在活性（Fv/Fm）、最大光化学速率（Fv/Fo）、光合性能指数（PIabs）和量子产额（φEo）均有不同程度降低。2）磁化水灌溉提高镉胁迫植株高生长及根茎叶干物质量,增加植株根系长度及表面积;同时,叶绿素a、叶绿素b和类胡萝卜素含量在0 μmol·L-1和100 μmol·L-1镉胁迫下分别提高16.99%、40.20%,8.67%、39.10%和17.32%、50.52%（P<0.05）;Gs、Ci及WUE显著升高,Tr则降低24.20%、23.33%、12.06%（P<0.05）;另外,Fv/Fm、Fv/Fo、PIabs显著升高（P<0.05）。综上所述,磁化水灌溉处理有助于提高镉胁迫下欧美杨幼苗光合色素含量,维持光合机构功能,增强光合碳同化速率,减轻镉胁迫对植株生长发育的抑制。 相似文献
4.
CO2浓度升高对不同水分条件下冬小麦生长和水分利用的影响 总被引：1，自引：1，他引：0
以CO2浓度升高为主要特征的气候变化对作物生长发育及产量形成的影响日益受到重视。冬小麦是我国主要粮食作物之一, 主要分布在干旱及半干旱地区, 且生长期内多干旱少雨。研究不同水分条件下冬小麦的生长变化及水分利用对CO2浓度升高的响应具有重要的科学和实践意义。本研究在封顶式生长室中对2个土壤水分水平[适宜水分: 70%~80%田间持水量; 干旱胁迫: 50%~60%田间持水量]的盆栽冬小麦进行了CO2熏蒸试验[背景大气浓度: (396.1±29.2) μmol·mol-1; 升高的浓度: (760.1±36.1)μmol·mol-1]。对小麦植株生理指标、生物量、产量、耗水量和水分利用效率(WUE)等的研究结果表明, 与背景大气CO2浓度相比, CO2浓度升高可促进冬小麦生长, 其地上生物量显著增加, 适宜水分和干旱胁迫条件下分别增加了28.6%和18.6%; 籽粒产量显著增加, 适宜水分和干旱胁迫条件下分别增加了32.6%和22.6%; CO2浓度升高主要通过增加穗粒数提高籽粒产量, 穗粒数在适宜水分条件下提高24.3%, 干旱胁迫条件下提高15.5%, 对千粒重没有显著影响。CO2浓度升高使群体和产量WUE显著提高, 在适宜水分条件下提高幅度较大, 分别提高17.7%和24.8%。CO2浓度升高显著提高了叶片光合速率(Pn)、降低了气孔导度(Gs)和蒸腾速率(Tr); 在适宜水分和干旱胁迫下Pn分别提高15.6%与12.9%, Gs分别降低22.7%与18.2%, Tr分别降低8.9%与7.5%。CO2浓度升高提高了叶片水势及叶绿素含量; 在适宜水分条件下叶片水势提高幅度较大, 为7.7%; 叶片叶绿素含量在2种水分条件分别提高7.5%与3.8%。由以上试验结果可得出: CO2浓度升高对冬小麦的生长、产量及水分利用效率均具有促进作用, 而且在土壤水分状况较好时, 这种作用效果更明显; CO2浓度升高主要通过增加穗粒数来促进产量提高。 相似文献
5.
不同利用方式红壤反硝化势和气态产物排放特征 总被引：1，自引：1，他引：1
采用厌氧培养-乙炔抑制法测定了4种不同利用方式红壤的反硝化势和气态产物N2O和N2的排放速率。结果表明，不同利用方式红壤反硝化势和N2O和N2的排放速率差异明显，土壤反硝化势强弱顺序依次为：竹林>茶园>林地>旱地。反硝化势与土壤有机碳(P<0.05)、厌氧培养期间土壤CO2累积排放量(P<0.01)、nirS基因丰度( P<0.05)和nirK基因丰度(P<0.05) 呈显著正相关关系。逐步回归分析结果表明，CO2累积排放量表征的易矿化碳是造成不同利用方式红壤反硝化势差异的主要原因，可以解释反硝化势变化的66%(P<0.01)。不同利用方式红壤N2O和N2排放速率差异明显，旱地红壤N2O和N2排放速率均最低，表明土壤pH的提升并没有增加旱地红壤的反硝化损失风险和N2O排放速率。土壤易矿化有机碳含量也是影响不同利用方式红壤N2O和N2排放速率的主要因素。反硝化功能基因nirS、nirK和nosZ的丰度均与CO2累积排放量呈显著正相关关系，进一步支持了土壤易矿化有机碳含量是影响不同利用方式红壤反硝化势和气态产物排放的主要因子。土壤pH是影响不同利用方式红壤反硝化气态产物N2/N2O的主要因素，但是pH影响红壤N2/N2O的微生物机制仍需要进一步研究。 相似文献
6.
模拟CCS技术CO2泄露对C4作物种子萌发的影响 总被引：1，自引：0，他引：1
模拟CCS技术CO2泄露对C4作物种子萌发的影响,以期为CCS技术CO2泄露后可能产生的环境影响提供基础性资料。利用CO2人工气候箱,模拟CCS技术CO2泄露产生的高浓度CO2环境,研究在CO2分别为正常大气CO2浓度(对照组),10000,20000,40000,80000 mg/kg时,对玉米、高粱、谷子、糜子4种C4作物发芽率、发芽势以及平均发芽天数的影响。高浓度CO2对玉米发芽率无明显影响,而高粱、谷子和糜子分别在10000,20000, 20000 mg/kg时发芽率达到最高值;高浓度CO2对玉米发芽势亦无明显影响,而高粱、谷子和糜子均在20000 mg/kg时发芽势达到最高值;高浓度CO2对4种C4作物发芽天数均产生较小影响,其中,对糜子影响较为显著。在不同CO2浓度范围内对C4作物种子发芽率分别有促进和抑制作用,促进和抑制作用不是很显著,其中,促进范围1%~5%,抑制范围1%~4%;高浓度CO2对C4作物种子发芽势有比较显著的促进作用,较对照组,发芽势的促进范围为9%~16%;高浓度CO2对4种C4作物发芽天数均产生较小影响。 相似文献
7.
秸秆还田替代化肥对黄土旱塬小麦产量及水肥利用的影响 总被引：1，自引：0，他引：1
为研究不同秸秆还田量替代部分化肥后对黄土高原冬小麦产量、水肥利用效率和硝态氮积累特征的影响。于2018—2021年在晋南黄土旱塬冬小麦种植区,设置秸秆不还田(S0)、秸秆半量还田(S1/2)、秸秆全量还田(S1)、秸秆2倍量还田(S2)4个还田量处理,研究不同秸秆还田量替代化肥对冬小麦产量形成、水肥利用效率及土壤硝态氮残留的影响。结果表明:在黄土旱塬麦区,秸秆还田替代8.3%~31.9% N和15.7%~63.2% P2O5的基础上,冬小麦产量总体随秸秆还田量增加而增加,且在降水丰沛年份,增加秸秆还田量可产生更大的产量效应。3年试验总体表明,S2处理冬小麦平均产量分别较S0、S1/2和S1处理分别高17.5%(P＜0.05),10.4%(P＜0.05),4.3%。连续3年秸秆还田均提高了冬小麦穗数,S2处理冬小麦平均单位面积穗数分别较S0、S1/2和[JP]S1处理高17.1%(P＜0.05),12.3%(P＜0.05),3.6%,不同处理间穗粒数和千粒重差异不显著。播前2 m土壤贮水量总体随着还田量的增加而增加,试验期间S2处理平均贮水量较S0提高8.3%(P＜0.05)。冬小麦生育期耗水量也表现为随着还田量的增加而增加,S2处理平均耗水量较S0处理增加了10.0%(P＜0.05)。不同处理间水分生产效率差异不显著,平均为14.9 kg/(hm2·mm)。在秸秆还田替代部分化肥基础上,旱塬冬小麦肥料利用效率随着秸秆还田量的增加而增加,其中,S2处理平均氮肥偏生产力(PFPN)、氮肥农学效率(AEN)、氮肥当季回收率(REN)和磷肥偏生产力(PFPP)较S0处理分别提高66.4%,155.8%,113.5%,105.2%。连续3年秸秆不还田使0—2 m土壤硝态氮残留量较2018年播前提高100.6%,并随水向下淋溶在深层土壤中累积,而秸秆还田处理2 m土层硝态氮累积量均低于2018年播前,S2处理2 m土壤硝态氮残留量最低,为244.8 kg/hm2。综合考虑,晋南黄土旱塬麦区,在秸秆还田替代8.3%~31.9% N和15.7%~63.2% P2O5基地上,可增加播前土壤底墒,降低肥料残留,并提高肥料利用效率,进而提高冬小麦产量,其中,以2倍秸秆还田量(平均为7 477 kg/hm2)产生的产量和水肥效应最佳。研究结果可为推进旱作麦区面源污染防控和冬小麦高产高效绿色生产提供理论依据。 相似文献
8.
短期干旱胁迫下棉花气孔表现及光合特征研究 总被引：3，自引：0，他引：3
研究气孔对干旱胁迫的响应有助于了解气孔调节真实行为和提高水分利用效率。本研究以‘国欣9号’为供试棉花品种,在人工气候室利用营养液培养,设置加入PEG-6000浓度为0（对照）、1.5%、3.0%和4.5% 4个处理,处理后1~7 d每隔1 d连续测定其气孔形态、光合和叶绿素荧光指标。结果表明：加入PEG-6000 1 d后,随着处理进程的延长,棉花叶片水势、气孔长度、宽度和开度、净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）、胞间CO2浓度（Ci）、最大光化学效率（Fv/Fm）和实际光化学量子产量（Yield）均呈下降趋势,气孔密度和非光化学淬灭系数（NPQ）呈上升趋势;不同处理之间,随着干旱胁迫程度增加,也表现出相似趋势。处理后5 d和7 d,与正常处理相比,1.5%、3.0%和4.5%处理棉花气孔长度、宽度、水势、Pn、Gs、Tr和Ci均差异显著（P<0.05）,气孔长度降低幅度最小（1.17%~2.61%）,Gs降低幅度最大（61.62%~69.09%）,Tr降低幅度为37.62%~67.48%。相关分析表明,棉花气孔长度、宽度和开度之间极显著正相关（P<0.01）,气孔宽度和气孔密度不相关。气孔长度、宽度和开度与Pn和Yield极显著正相关（P<0.01）,与NPQ极显著负相关（P<0.01）,与Gs、Tr和Fv/Fm相关不显著。综上,棉花在PEG-6000诱发干旱后,通过降低气孔开度和增大气孔密度降低净光合速率和气孔导度,叶绿素荧光指标Yield和NPQ比Fv/Fm对干旱更敏感。 相似文献
9.
为探究长期秸秆覆盖免耕对黑土坡耕地土壤结构的影响以及水土保持效应,通过秸秆覆盖免耕(NT)和传统顺坡耕作(CT)2组长期定位田间试验,对土壤结构、土壤保水能力、保土效应作对比分析。结果表明:NT与CT相应性状比较,土壤容重没有显著增加(P＞0.05),在0—20 cm土层,虽总孔隙度和非毛管孔隙度低,但增加了土壤毛管孔隙度和水稳性大团聚体(WR0.25)含量,WR0.25含量和平均重量直径(MWD)差异均达到显著水平(P＜0.05);分别提高了垄台土壤初始入渗和稳定入渗速率28.8%,24.7%;0—10 cm土层,饱和含水量和田间持水量差异均达到显著水平(P＜0.05);减少了产流次数、径流量和土壤流失量分别为11次,86.6%和98.9%,有效地遏制了水土流失。研究结果表明,长期连续秸秆覆盖免耕是一项有利于土壤结构稳定和遏制土壤侵蚀的黑土地保护措施。 相似文献
10.
为阐明控释肥对冬小麦-夏玉米轮作体系作物产量、温室气体排放和硝态氮残留的影响,该研究以郑单958（夏玉米）和济麦22（冬小麦）为供试材料,设不施氮对照（CK）、常规施氮（FFP）、优化施氮（OPT）、含30%控释尿素的控释掺混肥（夏玉米）和含50%控释尿素的控释掺混肥（冬小麦）（CRBF1）、含50%控释尿素的控释掺混肥（夏玉米）和含70%控释尿素的控释掺混肥（冬小麦）（CRBF2）共5个处理,对比分析了不同处理的冬小麦、夏玉米及周年产量、温室气体排放和土壤硝态氮残留的差异。结果表明,施氮可显著提高麦玉轮作系统单季和周年作物产量（P<0.05）。与FFP相比,CRBF1和CRBF2处理的夏玉米、冬小麦和周年产量分别提高了1.4%～3.0%、1.9%～3.4%和1.6%～3.1%（P>0.05）。施氮显著增加了麦玉轮作体系的土壤N2O和CO2的周年排放（P<0.05）。CRBF1和CRBF2处理的土壤N2O周年排放总量较FFP处理显著降低了27.7%～34.6%（P <0.05）。施氮显著增加了麦玉轮作体系的周年全球增温潜势（GWP）（P<0.05）。CRBF1和CRBF2处理的周年GWP较FFP处理降低了4.2%和5.7%,其中CRBF2处理差异显著（P<0.05）。施氮降低了麦玉轮作体系的周年温室气体排放强度（GHGI）。CRBF1和CRBF2处理的周年GHGI较FFP处理降低了5.6%～8.6%（P>0.05）。与FFP相比,CRBF1和CRBF2处理的100~200 cm土层硝态氮残留降低30.6%～34.3%（P<0.05）,减少了硝态氮淋失风险。综上所述,控释掺混肥在稳定作物产量、减少温室气体排放和土壤硝态氮残留方面具有积极作用,研究结果可为麦玉轮作体系的轻简高效氮肥管理提供数据支持和理论支撑。 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.
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
18.
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
19.
《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
20.
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