Impact of floor management practices on the growth of groundcover species and soil properties in an apple orchard in northern China

Tillage and groundcover are the two mainly used management practices in orchard. Only small portion of orchard has been treated with groundcover in China, which would restrict our understanding of the scientific management of apple orchard. This study aimed to investigate the impact of different groundcover treatments on the plant growth of groundcover species and soil properties in an apple orchard near Beijing, northern China. Six commonly used groundcover species were chosen to grow underground. Our results showed that groundcover species had significant greater maximum photosynthesis rate (P_max) than weeds in control plots. Meanwhile, groundcover treatments could largely improve the microclimate of orchard compared with tillage treatment. Among all the groundcover species, alfalfa was proven to be the most appropriate species grown underground in apple orchard for its high P_max and high above-ground biomass. Groundcover treatments had little impact on soil bulk density, soil porosity and surface soil organic carbon (SOC) content. However, significantly greater deep soil organic carbon contents were found in two grass species, and significantly higher soil available nitrogen (N) contents were found in two leguminous species respectively. Our results indicated that groundcover treatment would be a sustainable management practice for apple orchard in northern China.     

陇东红富士果树养分回流对土壤表层管理的响应

地处陇东黄土高原的庆阳市苹果园普遍缺乏有效的土壤表层管理措施,以盛果期的"红富士"果树为对象,研究不同土壤表层管理方式在养分回流期对苹果树体贮藏养分的动态变化。研究结果表明:优化覆膜(T2)与优化覆草(T3)一年生枝条叶片的叶绿素含量均显著高于常规处理(T1)。T2和T3处理的一年生春梢、秋稍和封顶枝中的碳素贮藏物质(可溶性糖、淀粉)和氮素贮藏物质(总游离氨基酸、可溶性蛋白质)的含量均显著高于T1,T3比T2处理对碳素贮藏物质含量的提升效果更为明显。此外,相同枝条类型不同组织中的贮存养分含量不同,可溶性糖和可溶性蛋白质的含量表现为表皮积聚,韧皮部木质部,淀粉与总游离氨基酸含量表现为主轴积聚,木质部韧皮部。不同枝条类型中贮藏物质的含量整体表现为秋梢封顶枝春梢,秋梢在提升养分贮藏水平中起到了重要作用。     

渭北旱塬苹果园不同水肥管理模式下的土壤水分差异

为了探究渭北旱塬苹果园不同水肥管理模式下的土壤水分差异,于2013—2016年在地处渭北旱塬的陕西省白水县田家洼村进行了田间试验,设置了3个不同果园水肥管理方式:农户模式(单施化肥,FM)、现有模式(推荐施肥配合地膜覆盖,EM)、优化模式(有机无机肥配施配合双元覆盖,OM),并对0~300 cm土层土壤水分进行了测定.结果表明:优化模式可以显著提高0~200 cm土层土壤贮水量,0~100 cm土层土壤含水量在干旱季节较农户模式和现有模式分别增加5.6%和15.3%,优化模式200~300 cm土层土壤水分相对亏缺指数低于现有模式,在干旱年份可以提高降雨入渗,降雨入渗达到300 cm,同时优化模式可以提高果园0~300 cm土层土壤降水补充量,稳定土壤水分变化,有效缓解了深层土壤干燥化程度.优化模式4年平均产量较农户模式和现有模式分别提高36.6%和22.5%.综上,优化模式可以通过提高土壤有效含水量,改善浅层和深层水分状况,提升土壤水分利用效率,在提高产量的同时,缓解土壤深层干燥化程度.     

不同地表覆盖方式对苹果园土壤性状及果树生长和产量的影响

以黄土高原9年生红富士果园生态系统为对象,研究不同地表覆盖模式（清耕、生草覆盖、地膜覆盖、秸秆覆盖和砂石覆盖）对果园土壤性状及果树生长和产量的影响.结果表明：生草覆盖土壤水分剖面分异最低,砂石覆盖土壤水分剖面分异最高;砂石覆盖提高了根层水分含量,有利于果树对水分的利用.不同地表覆盖模式土壤热量状况变化显著,处理间差异明显,极端最高温度下降,但地膜覆盖处理夏季地温超过果树根系生长的上限温度,对果树根系生长和生理功能发挥不利.除地膜覆盖外,其他地表覆盖模式均能提高土壤CO₂释放速率,其中生草覆盖的效果最为显著.不同地表覆盖模式对果树枝条类型比例及产量影响较大,砂石覆盖处理的中短枝比例和果实产量最高;生草覆盖处理的果实产量最低.因子分析结果表明,对于黄土高原沟壑区盛果期果园,砂石覆盖处理是较为适宜的地表覆盖模式.     

长江上游不同植物篱系统的土壤物理性质

在长江上游现有植物篱调查的基础上,对3种不同植物篱(乔木类、灌木类和草本类)不同位置的土壤物理性质进行了分析.结果表明:与植物篱带间相比,研究区3种不同类型植物篱带内土壤物理性质均得到了显著改善和提高;乔木类、草本类和灌木类植物篱带内土壤孔隙度、含水量、饱和导水率、水稳性团聚体含量、抗蚀指数、抗冲指数和土壤粘粒含量平均值分别提高了18.8%、30.1%、12.9%、139.3%、108.3%、95.9%和25.5%,土壤容重和土壤沙粒含量分别平均减小17.3%和9.6%;3种不同植物篱带内的土壤物理性质存在差异性,乔木类植物篱带内土壤抗冲性指数最大,灌木类植物篱带内土壤孔隙度、含水量、饱和导水率、抗蚀指数、水稳性团聚体含量、土壤粘粒含量高于乔木类和草本类,其土壤容重则低于乔木类和草本类;植物篱对植物篱-坡耕地系统内不同位置土壤物理性质影响程度的差异导致了土壤物理性质各指标在植物篱带内、带上、带下和带间坡耕地也存在一定的变异性,乔木类植物篱土壤水分含量、抗蚀指数、饱和导水率和土壤粘粒含量的变异系数大于灌木类和草本类植物篱,灌木类植物篱土壤容重、孔隙度、水稳性团聚体含量和抗冲指数的变异系数高于乔木类和草本类植物篱...     

不同耕作措施下旱地农田土壤呼吸及其影响因素

为探讨耕作措施对旱地农田土壤呼吸的影响,采用动态气室法在山西寿阳地区对秸秆还田、免耕覆盖、浅旋耕、常规耕作4种耕作措施下玉米生长季土壤呼吸及影响因子进行了测定和分析。结果表明,4种耕作措施下土壤呼吸速率的日和季节变化规律明显,均呈单峰型,呼吸速率的日峰值出现在11:30 13:30,呼吸速率的季节峰值出现在7月上旬至中旬。浅旋耕、秸秆还田、常规耕作、免耕覆盖措施整个生长季平均土壤呼吸速率分别为2.82、2.77、2.64μmolCO.2m-.2s-1和2.49μmolCO.2m-.2s-1,处理间无显著差异。研究结果还显示土壤温度和湿度是影响旱地农田土壤呼吸的主要因子,二者分别解释了土壤呼吸季节变化的55%78%,20%43%。4种措施下土壤呼吸的温度敏感系数Q10值在2.19 3.07之间,大小依次为免耕覆盖浅旋耕秸秆还田常规耕作。对水分的敏感性依次为免耕覆盖秸秆还田浅旋耕常规耕作。     

不同管理模式对温室土壤螨群落结构的影响

为了解日光温室内不同农业管理模式对土壤螨群落的影响,以日光温室长期定位试验为研究对象,于2012年8月至2012年12月进行了5次取样,调查了有机(ORG)、无公害(LOW)和常规(CON)管理模式下土壤螨的丰度与群落结构。结果显示:管理模式对螨的丰度、各亚目的比例、菌食性隐气门螨和捕食性螨比例均无显著影响,仅对菌食性非隐气门螨和食线虫螨有显著影响。土壤螨的总数及各营养类群的数量呈现不同程度的时间波动,且波动程度在不同的管理模式下存在差异。粉螨是温室土壤中最为丰富的类群(平均37.8%)。尽管螨的类群数目呈现ORG(26)LOW(21)CON(18)的趋势,但香农指数和优势度指数没有显著变化。总之,在高投入、高扰动日光温室环境中,管理模式对土壤螨的数量和群落结构影响均较小。     

长期生草对柑橘园土壤化学及生物学性质的影响

以柑橘园清耕、自然生草和人工生草3种管理模式为研究对象,对其土壤化学及生物学性质进行测定,探明了长期生草对柑橘园不同土层土壤碳氮磷、微生物生物量碳氮磷、酶活性的影响及其相互关系。结果表明：生草类型和土层显著影响土壤碳氮磷养分含量、微生物生物量碳氮磷含量和相应的酶活性,但两者互作仅对β-葡萄糖苷酶、N-乙酰氨基葡萄糖苷酶和亮氨基酸氨基肽酶有显著影响(P<0.05)。总体上,土壤生物化学性质在生草类型间表现为人工生草>自然生草>清耕;在土层间表现为0—10 cm>10—20 cm>20—40 cm。冗余分析表明,前两轴土壤化学及生物学指标解释了80.2%土壤酶活性的变化,且主要表现为正效应。土壤化学及生物学指标对土壤酶活性的影响也因生草类型和土层而异,人工生草在各土层中对β-葡萄糖苷酶、纤维二糖水解酶、多酚氧化酶、N-乙酰氨基葡萄糖苷酶、亮氨基酸氨基肽酶和酸性磷酸酶6种土壤碳氮磷酶活性的影响均为正效应,而自然生草仅在0—20 cm土层中对β-葡萄糖苷酶和纤维二糖水解酶活性产生正效应,两种生草类型土壤酶活性均在0—10 cm土层受土壤碳氮磷等因子影响最为突出。因...     

干旱区绿洲农田不同种植模式和秸秆管理下土壤质量评价

研究干旱区绿洲农田不同种植模式和秸秆管理下土壤有机碳及其酶活性的变化,揭示农业管理措施对土壤质量的影响,以期为干旱区农业资源高效利用及可持续发展提供理论依据.在作物种植规划区,选择新疆主要农作物棉花、小麦、玉米,设计长期连作及轮作试验.结果表明:轮作处理土壤有机碳(SOC)、微生物生物量碳、易氧化有机碳、水溶性有机碳、热水溶性有机碳含量较连作处理分别提高了3.6%~9.9%、41.8%~98.9%、3.3%~17.0%、11.1%~32.4%、4.6%~27.5%;秸秆还田处理较秸秆不还田处理分别提高了12%~35.9%、22.4%~49.7%、30.7%~51.0%、10.6%~31.9%、41.0%~96.4%.轮作处理土壤过氧化氢酶、脱氢酶、β-葡萄糖核苷酶、蔗糖酶、纤维素酶活性较连作处理分别提高了6.4%~10.9%、6.6%~18.8%、5.9%~15.3%、10.0%~27.4%、28.1%~37.5%;秸秆还田处理较-秸秆不还田处理分别提高了31.4%~47.5%、19.9%~46.6%、13.8%~20.7%、19.8%~55.6%、54.1%~70.9%.相关性分析表明,SOC及其活性组分与土壤酶活性之间有极显著的正相关关系,利用土壤活性有机碳组分和酶活性变化可有效表征农田SOC和土壤质量变化.通过因子分析综合评价得知,在干旱区农业生产中,短期连作棉花兼实施秸秆还田可提高SOC及其活性组分含量和酶活性,合理轮作可有效缓解连作障碍,使土壤质量得到进一步改善,有利于农田土壤的可持续利用.     

南亚热带不同植被恢复模式下土壤理化性质

分析了广西大青山南亚热带11种植被恢复模式下（1种天然次生林、2种人工针叶林、5种人工常绿阔叶林、2种人工针阔混交林和1种灌丛）土壤理化性质的变化特征.结果表明:不同植被恢复模式下土壤理化性质存在明显差异.其中,次生林林地土壤的物理性质良好,2种针叶林较差.2种针阔混交林土壤容重较小,土壤总孔隙度、土壤持水量均高于其他人工纯林;而5种人工常绿阔叶林的土壤孔隙度差异不明显.次生林土壤除全K低于柚木林外,其余养分含量均明显高于人工林,C/N和pH值相对较低.与荒草灌丛相比,9种人工林的土壤养分变化明显,全N和速效P含量均呈增加趋势;2种针叶纯林的土壤养分含量较低,但与红椎混交后,土壤养分含量明显改善,C/N值降低.     

不同连作年限甜瓜种植土壤性质和微生物多样性

[背景]连作种植和化肥、农药过量施用导致设施甜瓜土壤质地恶化、病害严重,甜瓜产量和质量下降.[目的]明确甜瓜连作种植年限对土壤化学性质、土壤酶活性和微生物多样性的影响.[方法]以甜瓜种植1年、5年和10年的温室耕层土壤为研究对象,采用常规分析方法、土壤酶活测定试剂盒、稀释涂布平板法和Illumina MiSeq高通量测...     

Intensive measurement of nitrous oxide emissions from a corn–soybean–wheat rotation under two contrasting management systems over 5 years

No‐tillage (NT), a practice that has been shown to increase carbon sequestration in soils, has resulted in contradictory effects on nitrous oxide (N₂O) emissions. Moreover, it is not clear how mitigation practices for N₂O emission reduction, such as applying nitrogen (N) fertilizer according to soil N reserves and matching the time of application to crop uptake, interact with NT practices. N₂O fluxes from two management systems [conventional (CP), and best management practices: NT + reduced fertilizer (BMP)] applied to a corn (Zea mays L.), soybean (Glycine max L.), winter‐wheat (Triticum aestivum L.) rotation in Ontario, Canada, were measured from January 2000 to April 2005, using a micrometeorological method. The superimposition of interannual variability of weather and management resulted in mean monthly N₂O fluxes ranging from − 1.9 to 61.3 g N ha⁻¹ day⁻¹. Mean annual N₂O emissions over the 5‐year period decreased significantly by 0.79 from 2.19 kg N ha⁻¹ for CP to 1.41 kg N ha⁻¹ for BMP. Growing season (May–October) N₂O emissions were reduced on average by 0.16 kg N ha⁻¹ (20% of total reduction), and this decrease only occurred in the corn year of the rotation. Nongrowing season (November–April) emissions, comprised between 30% and 90% of the annual emissions, mostly due to increased N₂O fluxes during soil thawing. These emissions were well correlated (r²= 0.90) to the accumulated degree‐hours below 0 °C at 5 cm depth, a measure of duration and intensity of soil freezing. Soil management in BMP (NT) significantly reduced N₂O emissions during thaw (80% of total reduction) by reducing soil freezing due to the insulating effects of the larger snow cover plus corn and wheat residue during winter. In conclusion, significant reductions in net greenhouse gas emissions can be obtained when NT is combined with a strategy that matches N application rate and timing to crop needs.     

Soil carbon dioxide efflux determined from large undisturbed soil cores collected in different soil management systems

The aim of this study was to evaluate a measuring technique for determining soil CO₂ efflux from large soil samples having undisturbed structure under controlled laboratory conditions. Further objectives were to use the developed measuring method for comparing soil CO₂ efflux from samples, collected in three different soil management systems at various soil water content values. The experimental technique was tested and optimised for timing of sampling by taking air samples after 1, 3 and 6 hours of incubation. Based on the results, the incubation time was set to three hours. The CO₂ efflux measured for different soil management systems was the highest in the no-till and the lowest in the ploughing treatment, which was in accordance with measurements on accessible organic carbon for microbes. An increase in CO₂ efflux with increasing soil water content was found in the studied soil water content range. Our results indicate that soil respiration rates, measured directly after tillage operations, can highly differ from those measured long after.     

祁连山不同类型草地的土壤理化性质与植被特征

祁连山草地生态系统在维护我国西部生态安全方面起着举足轻重的作用。为了解祁连山不同类型草地土壤水分、养分等理化性质与植被分布特征,及土壤理化性质与植被特征的相关关系,于祁连山选取7种类型的草地,测定土壤水分含量、养分含量、容重、颗粒组成和植被特征,计算土壤颗粒的分形维数、0～40 cm土层土壤有机碳、全氮和全磷储量、植物多样性指数。结果表明: 祁连山不同类型草地的土壤理化性质与植被特征差异显著,高寒草甸相比于其他类型草地具有较高的土壤水分、养分和黏粒含量,及较低的容重和砂粒含量;0～40 cm土层土壤有机碳、全氮、全磷储量变化范围分别为3084～45247、164～2358、100～319 g·m^-2,整体表现为有机碳和全氮含量高、全磷含量低;土壤全磷储量与植物多样性指数呈显著正相关关系,表明土壤全磷含量是祁连山草地植物多样性的关键影响因素。相比其他草地类型,高寒草甸具有较好的植被状况和土壤水分、养分条件。     

华南丘陵区不同土地利用方式下土壤呼吸

采用静态箱-气相色谱法对华南丘陵区针叶林和果园土壤呼吸及其主要影响因子进行了观测。结果表明:针叶林和果园含凋落物年均土壤呼吸分别为(1.96±0.09)和(6.56±0.32)kg.m-2.a-1;不含凋落物年均土壤呼吸分别为(1.60±0.07)和(5.30±2.80)kg.m-2.a-1。土地利用方式对土壤呼吸的影响较大,果园土壤呼吸明显大于针叶林(P<0.01)。针叶林和果园土壤呼吸季节变化模式相似,即雨季较高而旱季较低。不同土地利用方式下不同处理土壤呼吸均与地下5cm土壤温度、地表温度和气温呈显著指数相关。利用Q10模型计算出针叶林和果园土壤呼吸Q10值变化范围在1.73～3.30。土壤呼吸与土壤含水量显著相关。温度和土壤含水量能部分解释针叶林和果园土壤呼吸的季节变化。针叶林和果园由凋落物分解释放的CO2对土壤呼吸的贡献分别为18.14%和19.08%。     

Effects of legumes on soil physical quality in a maize crop

The effect of intercropped legumes and three N fertilizer rates in a continuous maize (Zea mays L.) cropping system on the physical properties of two soils were investigated for three years. The legumes, being a mixture of alfalfa, clover and hairy vetch, had a significant cumulative effect on some physical properties of both soil. The lowest stability and smallest mean weight diameter of soil aggregates were associated with monoculture maize plots. Aggregate size and stability were not affected by N fertilization at any of the rates of 0, 70, and 140 kg ha^-1 in intercropped plots, except that aggregate stability was actually reduced by N fertilization in one soil, the Ste. Rosalie clay. In maize plots in both soils, stability and size of soil aggregates were significantly increased with increased added N. Intercropped legumes significantly decreased dry bulk density and soil penetration resistance. Added N had no measurable influence on these compaction factors. Soil water properties were not significantly affected by either intercropping or N fertilization. Positive effects noted on soil aggregation and other physical properties in intercropped plots are the result of enhanced root activity, or incorporation of legumes as green manure, or both. Improvement of soil structure in maize plots associated with increasing N application was the result of increased maize-root residues.     

旱作农田不同耕作土壤呼吸及其对水热因子的响应

为研究旱作农田春玉米生育期不同耕作土壤呼吸变化特征及其对水热因子的响应情况,在山西省寿阳县旱农试验基地采用红外气体分析法测定了传统耕作(CT)、少耕(RT)和免耕(NT)土壤呼吸速率,并同步测定了各土层土壤水分、温度.研究表明:在春玉米生育期内,土壤呼吸速率均呈单峰型变化趋势,峰值出现在8月;传统耕作与少耕土壤呼吸速率变化趋势基本一致,而免耕土壤与前两者相比波动幅度较大;土壤呼吸峰值与水分、温度之间无明显相关,其余时期土壤呼吸与水分、温度因子具有良好的相关性;双因子模型较单因子模型能更好的描述土壤呼吸与水分、温度之间关系,基于水热双因子(10-20 cm)的指数-幂模型能够解释土壤呼吸变化的81％-87％ (P＜O.01);3种耕作土壤呼吸对水热因子协同影响的敏感性表现为CT＞NT＞RT.     

缙云山不同土地利用方式土壤有机碳组分特征

探讨了我国西南地区缙云山亚热带常绿阔叶林(以下简称林地)、果园、坡耕地以及撂荒地4种土地利用方式对土壤有机碳(SOC)组分含量及其分配比例的影响。采用物理分组技术,将SOC分为粗颗粒有机碳(cPOC)、细颗粒有机碳(fPOC)、微团聚体内颗粒有机碳(iPOC)、微团聚体内粉+黏颗粒(s+c_m)有机碳及粉+黏颗粒(s+c)有机碳。研究结果表明:在0—60cm的土壤深度范围内,SOC、cPOC、fPOC、iPOC、s+c_m组分以及s+c组分有机碳平均含量均为林地(9.02、3.14、1.61、0.33、0.42、3.53g/kg)显著高于果园(3.27、0.93、0.27、0.10、0.24、1.73g/kg)和坡耕地(2.58、0.51、0.10、0.12、0.08、1.77g/kg),说明林地开垦会导致SOC及各组分的流失;而撂荒地上述SOC及其各组分含量分别为14.90、5.17、2.36、0.42、0.59和6.36g/kg,均显著高于坡耕地,表明耕地撂荒后SOC及其组分能得到有效的恢复和截存。在SOC的各物理组分中,iPOC的有机碳分配比例最低,4种土地利用方式下均为3%左右;cPOC和fPOC作为活性较强的非保护有机碳库,在林地和撂荒地中所占SOC分配比例最高,达到50%以上;而果园和坡耕地中53um的粉+黏颗粒有机碳组成的化学保护有机碳库分配比例最大,分别为65.9%和71.6%,表明林地和撂荒地土壤有机碳的活性远远大于坡耕地及果园,支持更高的土壤肥力。在SOC及其组分中,fPOC可作为评估土地利用变化对土壤有机碳库影响的良好指标。     

玛纳斯河流域扇缘带不同植被类型下土壤物理性质

对生长在玛纳斯河流域扇缘带上的柽柳、盐穗木、白刺、猪毛菜4种植被类型下的土壤物理性质进行了研究.结果表明:在水平方向上,1m剖面内柽柳土壤pH值、全盐含量、土壤容重最小,分别为8.75、0.97g/kg和1.42g/cm3;土壤有机质、含水率、总孔隙度、毛管孔隙度均最大,分别为9.04 g/kg、16.67％、45.57％和36.18％,表明柽柳能够显著降低土壤盐分,改善土壤结构.沿垂直剖面,4种植被类型在表层0-20 cm土壤盐分均达到最高,出现盐分“表聚”现象而形成“盐霜”;随着土层深度增加,含水率和土壤容重均呈显著性升高,土壤有机质、田间持水量、总孔隙度、毛管孔隙度和非毛管孔隙度均呈显著性降低(P＜0.05).相关性分析显示,土壤有机质是引起其他土壤物理性质变化的主要原因.相比空裸地,4种植被覆盖类型1 m剖面内土壤有机质、总孔隙度和毛管孔隙度均呈显著性提高,土壤容重显著性降低,有机质分别提高了162.94％、82.94％、85.59％和27.94％,总孔隙度分别提高了44.90％、20.83％、36.06％和15.80％,毛管孔隙度分别提高了58.27％、30.71％、43.48％和25.72％,土壤容重分别降低了18.86％、10.86％、17.14％和7.43％,表明干旱荒漠区盐碱土上生长的不同盐生植物能够显著改善土壤质量.     

Olive orchard microbiome: characterisation of bacterial communities in soil-plant compartments and their comparison between sustainable and conventional soil management systems

ABSTRACT

Background

Beneficial bacteria-plant interactions play an important role in agriculture, positively affecting plant status and improving product quality. Bacterial endophytes contribute to host plant protection and survival.