局地尺度高寒草原土壤真菌多样性对地上植物多样性与生产力关系的调控作用     

王健宇  孟泽昕  王瑞  田晨  王新宇  陈康丽  王泽宇  呼天明  陈文青 《草地学报》2020,28(6):1498-1507

为研究局地尺度高寒草原土壤真菌多样性对地上植物多样性与生产力关系的调控作用，本研究以青海省湟源县局地尺度高寒草原为研究对象，对不同植物多样性梯度的地上生产力、土壤理化性状和土壤真菌多样性等指标进行调查、采样和分析。通过偏回归分析（partial least squares regression，PLSR）、方差分解分析（variance partitioning analysis，VPA）、构建结构方程模型（structural equation model，SEM）等分析手段，分析了土壤真菌多样性对地上植物多样性与生产力关系的调控作用。结果表明，高寒草原植物多样性与地上生产力存在显著线性正相关关系；土壤真菌多样性分别与植物多样性和地上生产力呈显著正相关关系；通过PLSR，VPA，SEM等方法控制土壤非生物因子效应后，真菌多样性与二者的显著正相关关系仍存在。综上所述，局地尺度下青海省湟源县高寒草原土壤真菌多样性是调控地上植物多样性与生产力正向关系的关键生物因子。  相似文献   

Nitrous oxide emission from a transplanted rice field in alluvial soil as influenced by management of nitrogen fertiliser          下载免费PDF全文

N. Bordoloi  K. K. Baruah  T. K. Maji 《Soil Use and Management》2016,32(4):573-582

We investigated nitrous oxide (N₂O) emission from an irrigated rice field over two years to evaluate the management of nitrogenous fertiliser and its effect on reducing emissions. Four forms of nitrogenous fertilisers: NPK at the recommended application rate, starch–urea matrix (SUM) + PK, neem‐coated urea + PK and urea alone (urea without coating) were used. Gas samples were collected from the field at weekly intervals with the static chamber technique. N₂O emissions from different treatments ranged from 11.58 to 215.81 N₂O‐N μg/m²/h, and seasonal N₂O emissions from 2.83 to 3.89 kg N₂O‐N/ha. Compared with other fertilisers, N₂O emissions were greatest after the application of the conventional NPK fertiliser. Moreover, SUM + PK reduced total N₂O emissions by 22.33% (P < 0.05) compared with NPK during the rice‐growing period (P < 0.05). The results indicate a strong correlation between N₂O emissions and soil organic carbon, nitrate, ammonium, above‐ and below‐ground plant biomass and photosynthesis (P < 0.05). The application of SUM + PK in rice fields is suitable as a means of reducing N₂O emissions without affecting grain production.  相似文献   

呼伦贝尔地区苜蓿人工草地CO_2通量变化特征     

徐丽君  徐大伟  杨桂霞 《草原与草坪》2015,(5):60-64

试验采用密闭箱技术对呼伦贝尔地区种植的苜蓿人工草地进行碳通量研究,采用反硝化-分解作用模型(DNDC)进行模拟。试验结果表明:对苜蓿人工草地CO2通量24h连续观测发现,CO2通量全天变化的平均值(238.15mg/(m2·h)与11∶00(245.32mg/(m2·h)的通量变化值接近,试验从早上9∶00~11∶00进行温室气体的采集方法合理、可行;在整个生长季变化表明,7、8月CO2通量变化较显著(P0.05),且受到降水的影响较大,伴随降水的发生,CO2通量会发生不同幅度的变化,土壤温度和含水量对CO2通量有一定的影响(r0.45,P0.05);通过DNDC模型的模拟,能较好的反映苜蓿人工草地CO2通量的变化情况,但模拟结果数值普遍有些偏高。  相似文献   

Managing soil quality for humanity and the planet     

Rattan LAL 《农业科学与工程前沿(英文版)》2020,7(3):251-253

Rather than a human-centric, the basic strategy of achieving Sustainable Development Goals must be focused on restoring and sustaining planetary processes. The urgency of meeting the demands of the humanity must be reconciled with the necessity of enhancing the environment. Increasing and restoring soil organic matter content of the degraded and depleted soils is critical to strengthening planetary processes.  相似文献   

Effects of cover crop growth and decomposition on the distribution of aggregate size fractions and soil microbial carbon dynamics          下载免费PDF全文

D. Linsler  M. Kaiser  R. Andruschkewitsch  C. Piegholdt  B. Ludwig 《Soil Use and Management》2016,32(2):192-199

Although the effects of cover crops (CC) on various soil parameters have been fully investigated, less is known about the impacts at different stages in CC cultivation. The objective of this study was to quantify the influence of CC cultivation stages and residue placement on aggregates and microbial carbon (C_mic). Additionally, the influence of residue location and crop species on CO₂ emissions and leached mineralized nitrogen (N_min) during the plant degradation period was also investigated. Within an incubation experiment, four CC species were sown in soil columns, with additional columns being kept plant‐free. After plant growth, the columns were frozen (as occurs in winter under field conditions) and then incubated with the plant material either incorporated or surface‐applied. With CC, concentrations of large and medium macroaggregates were twice that of the fallow, confirming positive effects of root growth. Freezing led to a decrease in these aggregate size classes. In the subsequent incubation, the large macroaggregates decreased far more in the samples with CC than in the fallow, leading to similar aggregate size distributions. No difference in C_mic concentration was found among the CC cultivation stages. CO₂ emissions were roughly equivalent to the carbon amounts added as plant residues. Comparison of columns with incorporated or surface‐applied residues indicated no consistent pattern of aggregate distribution, CO₂ emission or C_mic and N_min concentrations. Our results suggest that positive effects of CC cultivation are only short term and that a large amount of organic material in the soil could have a greater influence than CC cultivation.  相似文献   

基质分散萃取-高效液相色谱法对菠菜中噻虫胺残留的检测   总被引：1，自引：0，他引：1  

李广领  谷珊山  刘博  陈锡岭 《湖北农业科学》2016,(2):465-468

研究确立了乙腈为分散萃取溶剂,以羧基化双壁碳纳米管(DWCNTs-COOH)和石墨化碳黑(GCB)为基质分散材料的菠菜(Spinacia oleracea L.)样品中噻虫胺残留基质分散萃取前处理方法,建立并优化了乙腈等度洗脱的HPLC残留样品外标定量方法。结果表明,优化色谱条件下,噻虫胺标准样品的色谱保留时间为6.258 min,在0.05~100 mg/L范围内与对应色谱峰积分面积线性响应良好,回归方程为y=4.948 2x-1.316 9(R~2=0.999 7),噻虫胺在菠菜样品中0.1、0.5和5.0 mg/kg 3个水平的添加回收率均在85%以上,各添加水平的相对标准偏差均小于7%,该色谱条件下仪器检出限为0.052 7μg/L,方法的最低检测量为0.015 mg/kg。表明该残留样本前处理方法和样品检测方法简便、高效、经济、可靠,可满足噻虫胺在菠菜中的残留定量检测要求。  相似文献   

Ecological implications of motor oil pollution: Earthworm survival and soil health     

《Soil biology & biochemistry》2015

The nontarget effects of fresh and used motor oil were studied in a soil test system involving such criteria as earthworm survival, response of soil dehydrogenase and urease, and nitrification. When earthworms were exposed to motor oil-contaminated soil for 4 weeks, the observed median lethal concentrations (LC₅₀) were 40.33 and 3.88 g kg⁻¹ soil for fresh and used oil, respectively. Only fresh motor oil application increased earthworms' body weight even at the higher dose of 19 g kg⁻¹ soil. Gas chromatography/mass spectrometry revealed that used motor oil contained more of aromatic hydrocarbons and heavy metals than fresh oil. This disparity in the chemical composition might be the factor responsible for the significant toxicity of used motor oil towards earthworms. Activities of soil dehydrogenase and urease were significantly enhanced in presence of both the motor oils, while there was a significant inhibition in nitrification by the used motor oil even at a low concentration of 0.2 g kg⁻¹ soil. This study clearly demonstrated that earthworm survival and nitrification could serve as suitable indices to assess motor oil pollution in soil.  相似文献   

Vineyard soil bacterial diversity and composition revealed by 16S rRNA genes: Differentiation by geographic features     

《Soil biology & biochemistry》2015

Here, we examine soil-borne microbial biogeography as a function of the features that define an American Viticultural Area (AVA), a geographically delimited American wine grape-growing region, defined for its distinguishing features of climate, geology, soils, physical features (topography and water), and elevation. In doing so, we lay a foundation upon which to link the terroir of wine back to the soil-borne microbial communities. The objective of this study is to elucidate the hierarchy of drivers of soil bacterial community structure in wine grape vineyards in Napa Valley, California. We measured differences in the soil bacterial and archaeal community composition and diversity by sequencing the fourth variable region of the small subunit ribosomal RNA gene (16S V4 rDNA). Soil bacterial communities were structured with respect to soil properties and AVA, demonstrating the complexity of soil microbial biogeography at the landscape scale and within the single land-use type. Location and edaphic variables that distinguish AVAs were the strongest explanatory factors for soil microbial community structure. Notably, the relationship with TC and TN of the <53 μm and 53–250 μm soil fractions offers support for the role of bacterial community structure rather than individual taxa on fine soil organic matter content. We reason that AVA, climate, and topography each affect soil microbial communities through their suite of impacts on soil properties. The identification of distinctive soil microbial communities associated with a given AVA lends support to the idea that soil microbial communities form a key in linking wine terroir back to the biotic components of the soil environment, suggesting that the relationship between soil microbial communities and wine terroir should be examined further.  相似文献   

有机改良剂对温室土壤及番茄质量的影响     

王文娇  曹晶晶  王世峰  李梅兰  侯雷平 《华北农学报》2017,32(4)

研究了优培-海藻生物有机肥(Y)、微生物菌肥(W)和腐植酸有机肥对日光温室土壤的理化性质、有效态微量元素含量、酶活性以及番茄品质等方面的影响,旨在探索快速、简易且廉价的土壤改良方法,为日光温室土壤改良及有机蔬菜生产提供理论依据。结果表明,不同土壤改良剂对土壤p H无显著影响,在番茄生育期内土壤p H值始终在7.0以上,没有出现酸化问题;拉秧后,除中量腐植酸有机肥(FM)外,其他各处理均能有效降低土壤EC值并达到极显著水平;各处理对提升有效态Mn、Zn和Fe含量的效果不显著,其中,仅高量腐植酸有机肥处理(FH)能同时提高开花结果盛期0~20 cm和20~40 cm土层的有效态Zn含量,与CK相比,分别增加10.8%和13.2%;不同土壤改良剂均可提高土壤脲酶和蔗糖酶活性;不同土壤改良剂对碱性磷酸酶的酶活性影响较小;微生物菌肥对酸性磷酸酶和过氧化氢酶的酶活性影响相对明显;不同土壤改良剂均能提高番茄可溶性固形物、可溶性糖、可滴定酸和维生素C的含量,其中,中量腐植酸有机肥处理提高了番茄的糖酸比。土壤改良剂可有效改善日光温室土壤特性及番茄品质。  相似文献   

渗灌次数对西北荒漠灌区紫花苜蓿栽培草地土壤化学性质的影响     

吴芳  李玉珠  师尚礼  陈春  贾福军  郑印江 《草地学报》2017,25(3)

渗灌是节水农业中最有效的措施之一,有利于作物产量和水分利用率的提高。本研究以甘肃省金昌市杨柳青公司紫花苜蓿‘艾迪娜’(M.sativa L.‘Aidina’)试验地渗灌区土壤为研究对象,通过田间试验与室内分析相结合的方法,研究不同渗灌次数(0次、1次、2次、3次)对苜蓿出苗期不同土层深度及管距位置土壤化学性质的影响。结果表明:在0~10cm和10~20cm土层深度,pH最高值均出现在管上,较CK升高了8.21%和8.68%,最低值都出现在管中,较CK降低了2.70%和3.37%;2水和3水均能显著提高不同土层深度及不同管距位置的pH值(P0.05)。不同渗灌次数,不同土层深度管中的水溶性盐含量均高于管上和管近,且最大值都出现在1水,较CK分别增加了83.26%和96.34%;不同土层深度,2水的水溶性盐含量平均值都低于1水和3水;不同渗灌次数,不同土层深度,钠离子和钾离子含量的最大值均出现在管中。不同渗灌次数,不同土层深度,管中的水解性氮含量均高于管上和管近,最大值都出现在1水管中,较CK分别增加了112.68%和34.48%。随着渗灌次数的增多,0~10cm土层深度不同管距的速效磷含量均呈现下降趋势,速效钾含量均呈现上升趋势。随着灌水次数的增加,不同土层深度及管位的有机质含量均呈现先上升后下降的趋势,2水显著提高了各位置土壤有机质含量(P0.05)。综上所述,渗灌2次比较好,土壤水溶性盐含量较低且有机质含量较高,利于苜蓿幼苗生长。  相似文献