农业废弃物及其制备的生物质炭对酸性土壤的改良作用

The liming potential of some crop residues and their biochars on an acid Ultisol was investigated using incubation experiments. Rice hulls showed greater liming potential than rice hull biochar, while soybean and pea straws had less liming potential than their biochars. Due to their higher alkalinity, biochars from legume materials increased soil pH much compared to biochars from non-legume materials. The alkalinity of biochars was a key factor aflecting their liming potential, and the greater alkalinity of biochars led to greater reductions in soil acidity. The incorporation of biochars decreased soil exchangeable acidity and increased soil exchangeable base cations and base saturation, thus improving soil fertility.     

亚热带湿润地区城市公园重建强度对其土壤酸化和土壤中重金属的影响

Soil quality is a major concern in the management of urban parks. In this study, the soils at 0–3, 3–13, and 13–23 cm depths were sampled from six urban parks, differing in reconstruction intensity(mainly changes made during conversion of natural forests into parklands), in the Pearl River Delta, China to determine how reconstruction intensity influenced the extent of acidification and heavy metal levels in the soils of urban parks in a humid subtropical environment. High reconstruction intensity(HRI) was practiced in three parks and low reconstruction intensity(LRI) in three other parks. The LRI soils were strongly to extremely acidic(with low exchangeable Ca, Mg, and K concentrations) while the HRI soils were much less acidic. Both total and extractable concentrations of soil heavy metals were related to the specific management practices and age of the park, but did not differ significantly between LRI and HRI parks or among soil depths. Soil p H was significantly related to soil exchangeable cation concentrations and base saturation but was weakly related or unrelated to soil heavy metal levels. Our results suggest that high intensity but not low intensity reconstruction significantly reduces the extent of soil acidification in the urban parks in a humid subtropical environment.     

南亚热带三种不同土地利用历史的森林生态系统土壤可交换阳离子对模拟氮沉降的响应

The effects of simulated nitrogen (N)deposition on soil exchangeable cations were studied in three forest types of subtropical China. Four N treatments with three replications were designed for the monsoon evergreen broadleaf forest (mature forest):control (0 kg N ha^-1 year^-1), low N (50 kg N ha^-1 year^-1), medium N (100 kg N ha^-1 year^-1)and high N (150 kg N ha^-1 year^-1), and only three treatments (i.e., control, low N, medium N)were established for the pine and mixed forests. Nitrogen had been applied continuously for 26 months before the measurement. The mature forest responded more rapidly and intensively to N additions than the pine and mixed forests, and exhibited some significant negative symptoms, e.g., soil acidification, Al mobilization and leaching of base cations from soil. The pine and mixed forests responded slowly to N additions and exhibited no significant response of soil cations. Response of soil exchangeable cations to N deposition varied in the forests of subtropical China, depending on soil N status and land-use history.     

水溶性有机碳在各种粘土底土中的吸附：土壤性质的影响

Clay-rich subsoils are added to sandy soils to improve crop yield and increase organic carbon (C) sequestration; however, little is known about the influence of clay subsoil properties on organic C sorption and desorption. Batch sorption experiments were conducted with nine clay subsoils with a range of properties. The clay subsoils were shaken for 16 h at 4 ^oC with water-extractable organic C (WEOC, 1 224 g C L^-1) from mature wheat residue at a soil to extract ratio of 1:10. After removal of the supernatant, the residual pellet was shaken with deionised water to determine organic C desorption. The WEOC sorption was positively correlated with smectite and illite contents, cation exchange capacity (CEC) and total organic C, but negatively correlated with kaolinite content. Desorption of WEOC expressed as a percentage of WEOC sorbed was negatively correlated with smectite and illite contents, CEC, total and exchangeable calcium (Ca) concentrations and clay content, but positively correlated with kaolinite content. The relative importance of these properties varied among soil types. The soils with a high WEOC sorption capacity had medium CEC and their dominant clay minerals were smectite and illite. In contrast, kaolinite was the dominant clay mineral in the soils with a low WEOC sorption capacity and low-to-medium CEC. However, most soils had properties which could increase WEOC sorption as well as those that could decrease WEOC sorption. The relative importance of properties increasing or decreasing WEOC sorption varied with soils. The soils with high desorption had a low total Ca concentration, low-to-medium CEC and low clay content, whereas the soils with low desorption were characterised by medium-to-high CEC and smectite and illite were the dominant clay minerals. We conclude that WEOC sorption and desorption depend not on a single property but rather a combination of several properties of the subsoils in this study.     

湿地土壤NH4+吸附解吸对冻融循环的响应

Nitrogen (N) cycling in boreal peatland ecosystems may be influenced in important ways by freeze-thaw cycles (FTCs).Adsorption and desorption of ammonium ions (NH + 4) were examined in a controlled laboratory experiment for soils sampled from palustrine wetland,riverine wetland,and farmland reclaimed from natural wetland in response to the number of FTCs.The results indicate that freeze-thaw significantly increased the adsorption capacity of NH + 4 and reduced the desorption potential of NH + 4 in the wetland soils.There were significant differences in the NH + 4 adsorption amount between the soils with and without freeze-thaw treatment.The adsorption amount of NH + 4 increased with increasing FTCs.The palustrine wetland soil had a greater adsorption capacity and a weaker desorption potential of NH + 4 than the riverine wetland soil because of the significantly higher clay content and cation exchange capacity (CEC) of the riverine wetland soil.Because of the altered soil physical and chemical properties and hydroperiods,the adsorption capacity of NH + 4 was smaller in the farmland soil than in the wetland soils,while the desorption potential of the farmland soil was higher than that of the wetland soils.Thus,wetland reclamation would decrease adsorption capacity and increase desorption potential of NH + 4,which could result in N loss from the farmland soil.FTCs might mitigate N loss from soils and reduce the risk of water pollution in downstream ecosystems.     

长期种植苜蓿对中国半干旱地区黄土钾含量和粘土矿物的影响

Alfalfa cropping has been considered an efficient method of increasing soil fertility.Usually nitrogen increase in root nodules is considered to be the major beneficial effect.A 21-year time series (five sampling periods) of alfalfa cultivation plots on a loess soil,initially containing illite and chlorite,in Lanzhou of northwestern China was selected to investigate the relationships among alfalfa cropping,soil potassium (K) content and soil clay minerals.The results indicated that soil K significantly accumulated after cropping,with a peak value at about 15 years,and decreased afterwards.The accumulated K was associated with the K increase in the well-crystallized illite,which was not extracted by the traditional laboratory K extraction methods in assessing bioavailability.The steep decline in soil K content after 15-year cropping was in accord with the observed fertility loss in the alfalfa soil.Plant biomass productivity peaked at near 9 years of culture,whereas soil K and clay minerals continued to increase until cropping for 15 years.This suggested that K increased in the topsoil came from the deep root zone.Thus alfalfa continued to store K in clays even after peak production occurred.Nitrogen did not follow these trends,showing a general decline compared with the native prairie soils that had not been cropped.Therefore,the traditional alfalfa cropping can increase K content in the topsoil.     

蚌壳用作土壤改良剂：对根际和非根际土壤和草地生产力的影响

Large quantities of mussel shells(66 000-94 000 t year 1),an alkaline material that can be used as a soil amendment,are generated as waste in Galicia,NW Spain.A field trial was carried out by planting different pasture species in a Haplic Umbrisol using a randomized block design with four blocks and six treatments(not amended control or soil amended with lime,finely ground shell,coarsely ground shell,finely ground calcined shell or coarsely ground calcined shell) to compare the effects of lime and mussel shells additions on a soil with a low cation exchange capacity and high Al saturation.The trial was established in March 2007,and samples of plants and soil were collected when plots were harvested in summer 2008(separating the bulk and rhizosphere soil).The soils were analyzed for pH,total C,total N,available P,exchangeable cations,effective cation exchange capacity and available micronutrients.Dry matter yield was measured in all plots and plants were analyzed for nutrients.Application of mussel shells and the commercial lime resulted in an increase in pH and exchangeable Ca and a decrease in exchangeable Al and Al saturation.The stability of pH over time was high.These effects were most noticeable in the rhizosphere.The amendment also had a positive effect on dry matter yield and concentration of Ca in the plant.     

有机质含量对人造技术土水分结构性质的影响

Constructed Technosols may be an alternative for creating urban green spaces. However, the hydro-structural properties emerging from the assembly of artefacts have never been documented. The soil shrinkage curve (SSC) could provide relevant structural information about constructed Technosols, such as the water holding capacity of each pore system (macropores and micropores). The objectives of this study were (i) to evaluate the SSC and water retention curve (WRC) to describe the structure of constructed Technosols and (ii) to understand the influence of organic matter content on soil hydro-structural properties. In this study, Technosols were obtained by mixing green waste compost (GWC) with the material excavated from deep horizons of soil (EDH). The GWC was mixed with EDH in six different volumetric percentages from 0% to 50% (GWC/total). The GWC and EDH exhibited highly divergent hydro-structural properties: the SSC was hyperbolic for GWC and sigmoid for EDH. All six mixture treatments (0%, 10%, 20%, 30%, 40% and 50% GWC) exhibited the classical sigmoid shape, revealing two embedded levels of pore systems. The 20% GWC treatment was hydro-structurally similar to the 30% and 40% GWC treatments; so, a large quantity of expansive GWC is unnecessary. The relation with the GWC percentage was a second-degree equation for volumetric available water in micropores, but was linear for volumetric available water in macropores and total volumetric available water. Total volumetric available water in the 50% GWC treatment was twice as high as that in the 0% GWC treatment. By combining SSCs and WRCs, increasing the GWC percentage increased water holding capacity by decreasing the maximum equivalent size of water-saturated micropores at the shrinkage limit and increasing the maximum equivalent size of water-saturated macropores, resulting in an increased range of pore diameter able to retain available water.     

长期施肥对黄棕壤细菌多样性的影响

[目的]基于武汉黄棕壤长期定位试验(1981—2016年),探究不同施肥措施下土壤肥力演变和土壤微生物多样性变化,为黄棕壤培肥以及农业绿色可持续发展提供依据.[方法]本研究采用Illumina MiSeq高通量测序技术和偏最小二乘路径模型(PLS-PM)综合分析了不施肥(CK)、氮磷钾(NPK)、常量有机肥(OM)、氮...     

生物炭对沙质土水分蒸发和导水率的影响

Biochar, as a kind of soil amendment, has important effects on soil water retention. In this research, 4 different kinds of biochars were used to investigate the influences of biochar addition on hydraulic properties and water evaporation in a sandy soil from Hebei Province, China. Biochar had strong absorption ability in the sandy soil. The ratio of water content in the biochar to that in the sandy soil was less than the corresponding ratio of porosity. Because of the different hydraulic properties between the sandy soil and the biochar, the saturated hydraulic conductivity of the sandy soil gradually decreased with the increasing biochar addition. The biochar with larger pore volume and average pore diameter had better water retention. More water was retained in the sandy soils when the biochar was added in a single layer, but not when the biochar was uniformly mixed with soil. Particle size of the added biochar had a significant influence on the hydraulic properties of the mixture of sand and biochar. Grinding the biochar into powder destroyed the pore structure, which simultaneously reduced the water absorption ability and hydraulic conductivity of the biochar. For this reason, adding biochar powder to the sandy soil would not decrease the water evaporation loss of the soil itself.     

镉胁迫下的实验室放线菌种群结构变化的DGGE分析

The actinomycete populations and functions in cadmium (Cd) contaminated soil were investigated by the cultivationindependent molecular methods. The genomic DNA was extracted and purified from soil adulterated with various concentrations of Cd in the laboratory. The partial 16S rDNA genes were amplified by polymerase chain reaction (PCR) using specific primers bound to evolutionarily conserved regions within these actinomycete genes. The diversity in PCRamplified products, as measured by denaturing gradient gel electrophoresis (EGGE), was used as a genetic fingerprint of the population. Principle component analysis and Shannon-Weaver diversity index (H) analyses were used to analyze the DGGE results. Results showed that the two principal components accounted for only a low level of the total variance. The value H in contaminated soil was lower than that in the control at later stages of cultivation, whereas at earlier stages it was higher. Among the six sampling time points, the first, fifth and sixth weeks had the highest values of H. Significantly negative correlations between bioavailable Cd concentration and H values existed in the samples from weeks 2 (R = 0.929, P < 0.05) and 4 (R =0.909, P < 0.05). These results may shed light on the effect of Cd on the soil environment and the chemical behavior and toxicity of Cd to actinomycetes.     

Bacterial Communities Responsible for the Decomposition of Rice Straw Compost in a Japanese Rice Paddy Field Estimated by DGGE Analysis of Amplified 16S rDNA and 16S rRNA Fragments

To estimate the succession and phylogenetic composition of the bacterial communities responsible for the decomposition of rice straw compost under flooded conditions during the cultivation period of paddy rice, denaturing gradient gel electrophoresis (DGGE) analyses targeting 16S rDNA and 16S rRNA, followed by sequencing were conducted in a Japanese paddy field. The DGGE bands of the bacterial communities in the rice straw compost were significantly more numerous in the DNA samples than in the RNA samples. Although the band number of the DNA samples was almost constant throughout the period, RNA samples showed fewer DGGE bands after mid-season drainage than before it. Thus, about 81% of the bacteria present in rice straw compost were considered to be metabolically "active" before mid-season drainage and about 62% after it. The changes in the DGGE patterns of bacterial DNA and RNA before and after mid-season drainage, respectively, were also revealed by cluster analysis and principal component analysis of the DGGE patterns. These results indicated that the bacterial communities of rice straw compost incorporated into flooded paddy fields changed gradually along with the decomposition, except for the period of mid-season drainage, but that they were influenced by mid-season drainage. Members of β-, γ- and δ-Proteobacteria, Cytophaga-Flavobacterium-Bacteroides (CFB) group, Chlorobia, Verrucomicrobia, Chloroflexi, Spirochaetes, Firmicutes (clostridia) and Actinobacteria were present during the decomposition of rice straw compost. Characteristic "active" bacteria among them were as follows: Clostridium, Acinetobacter (γ-Proteobacteria) and β-Proteobacteria before mid-season drainage, Flavobacterium, Chondromyces , Chlorflexi and δ-Proteobacteria after mid-season drainage, and Spirochaeta and myxobacteria throughout the period.     

cry1Ac/cpti转基因大米水稻土中微生物群落的多样性研究

Two types of cry1Ac/cpti transgenic rice(GM1 and GM2)and their parental non-cry1Ac/cpti rice(CK1 and CK2)were planted in the field at Wufeng,Fujian Province,China for four years to investigate the influence of genetically modified rice on diversity of bacterial and fungal community in the paddy soil.The community composition and abundance of bacteria or fungi in the paddy soil were assessed at different growth stages of rice by denaturing gradient gel electrophoresis and real-time polymerase chain reaction based on 16S rRNA gene or SSU rRNA gene in the 4th year after the experimental establishment.The composition of bacterial or fungal community changed during rice growth,while no significant differences were observed between the fields cultivated with GM1and CK1,or between the fields cultivated with GM2 and CK2 in either bacterial or fungal community composition.The copy numbers of bacterial 16S rRNA gene in the soils with CK1,CK2,GM1 and GM2 ranged from 5.64×1011to 6.89×1011copies g-1dry soil at rice growth stages,and those of fungal SSU rRNA gene from 5.24×108to 8.68×108copies g-1dry soil.There were no marked differences in the copies of bacterial 16S rRNA gene or fungal SSU rRNA gene between CK1 and GM1 or between CK2 and GM2at any growth stage of rice.Planting cry1Ac/cpti transgenic rice had no significant effect on composition and abundance of bacterial and fungal community in paddy soil during the rice growing season at least in the short term.     

苜蓿青贮过程中乳酸菌复合系Al2的接种效果及菌群的追踪

以苜蓿(Medicago sativa)为原材料，添加乳酸菌复合系Al2调制青贮苜蓿，并以不添加接种剂的苜蓿作为对照，分析苜蓿青贮过程中微生物区系变化及接菌的改善效果。通过提取青贮料中细菌的总DNA，通过聚合酶链式反应(PCR)扩增其16S rDNA V3区域，利用变性梯度凝胶电泳法(Denaturing Gradient Gel Electrophoresis, DGGE)分析青贮料中细菌的区系变化，并结合平板计数法对青贮料中的乳酸菌、一般细菌、霉菌进行动态分析。DGGE图谱结果显示自然青贮苜蓿的优势菌是戊糖片球菌(Pediococcus pentosaceus)。在接菌Al2的青贮料中，以植物乳杆菌(Lactabacillus plantarum)为主的Al2的成员菌迅速控制发酵过程，并且在发酵过程中稳定存在。与对照相比，添加乳酸菌剂能够提高乳酸菌的数量，在第2 d将青贮料的pH值降低到4.2，最后稳定到4.1，显著提高了乳酸生成量，降低了氨态氮的产生，明显改善了青贮饲料的发酵品质。     

Anammox反应器的启动及其菌群演变的研究

为了研究工艺条件对反应器内微生物多样性的影响,该论文采用城市污水处理厂活性污泥接种,通过培育硝化污泥,进行了启动厌氧氨氧化(Anammox)反应器的试验,并对启动过程中细菌的多样性变化作了跟踪研究。研究结果表明,以好氧活性污泥作为接种物,可成功地培育硝化生物膜;通过反应器运行条件的控制,硝化生物膜可从进行好氧氨氧化反应过渡到进行厌氧氨氧化反应。在此过程中,异养型细菌的数量大幅度下降,硝化细菌、反硝化细菌和厌氧氨氧化细菌的数量增大,推测它们都与厌氧氨氧化作用有关。运用PCR-DGGE技术证明,随着反应器运行时间的延长,菌群发生明显变化并呈现简化趋势。     

Application of DGGE analysis to the study of bacterial community structure in plant roots and in nonrhizosphere soil

To analyze the structure of bacterial communities in spinach roots and in the nonrhizosphere soil, we used PeR-amplified 16S rRNA gene fragments separated by denaturing gradient gel electrophoresis (DGGE). DGGE revealed a large number of band patterns, which were ascribed to various bacterial species composing each of the bacterial communities. The pattern from the roots was less complex than that from the soil. It is considered that DGGE analysis is suitable for studies of bacterial community structure in soil-plant ecosystems.     

Liming induces growth of a diverse flora of ammonia-oxidising bacteria in acid spruce forest soil as determined by SSCP and DGGE

The autotrophic ammonia-oxidising bacterial (AOB) community composition was studied in acid coniferous forest soil profiles at a site in southwestern Sweden 6 years after liming. Liming caused a significant increase in pH in the organic horizons, while the mineral soil was unaffected. The AOB communities were studied by single-strand conformation polymorphism (SSCP) in parallel with denaturing gradient gel electrophoresis (DGGE) analysis of partial 16S rRNA genes amplified by PCR using primers reported to be specific for β-Proteobacteria AOB, followed by nucleotide sequencing. High genetic diversity of Nitrosospira-like sequences was found in the limed soil profiles, whereas no AOB-like sequences were detected in the control soil at any depth, according to both the SSCP and DGGE analyses. This clearly showed that liming induced growth of a diverse flora of AOB at this forest site. Both Nitrosospira cluster 2 and cluster 4 sequences were present in the limed soil profiles, regardless of soil pH, but we found a higher number of sequences affiliated with cluster 4. The high lime dose seemed to affect the AOB community more than the low dose, and its effects reached deeper into the soil profile. Seven different Nitrosospira-like sequences were found 10 cm under the litter layer in the soil limed with the high dose, but only two in the soil amended with the low lime dose.     

利用PCR-DGGE技术研究长期自然恢复、种植作物和裸地条件下黑土土壤细菌群落结构变化

Soil microbial biomass and community structures are commonly used as indicators for soil quality and fertility. A investigation was performed to study the effects of long-term natural restoration, cropping, and bare fallow managements on the soil microbial biomass and bacterial community structures in depths of 0--10, 20--30, and 40--50 cm in a black soil (Mollisol). Microbial biomass was estimated from chloroform fumigation-extraction, and bacterial community structures were determined by analysis of 16S rDNA using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Experimental results showed that microbial biomass significantly declined with soil depth in the managements of restoration and cropping, but not in the bare fallow. DGGE profiles indicated that the band number in top 0--10 cm soils was less than that in depth of 20--30 or 40--50 cm. These suggested that the microbial population was high but the bacterial community structure was simple in the topsoil. Cluster and principle component analysis based on DGGE banding patterns showed that the bacterial community structure was affected by soil depth more primarily than by managements, and the succession of bacterial community as increase of soil depth has a similar tendency in the three managements. Fourteen predominating DGGE bands were excised and sequenced, in which 6 bands were identified as the taxa of Verrucomicrobia, 2 bands as Actinobacteria, 2 bands as α-Proteobacteria, and the other 4 bands as δ-Proteobacteria, Acidobacteria, Nitrospira, and unclassified bacteria. In addition, the sequences of 11 DGGE bands were closely related to uncultured bacteria. Thus, the bacterial community structure in black soil was stable, and the predominating bacterial groups were uncultured.     

施用生物有机肥抑制香蕉镰刀菌萎蔫病的研究

Fusarium wilt is one of the most serious diseases of banana plants caused by soil-borne pathogen Fusarium oxysporum f.sp. cubense(FOC). In this study a pot experiment was conducted to evaluate the effects of different bio-organic fertilizers(BIOs) on Fusarium wilt of banana, including the investigations of disease incidence, chitinase and β-1,3-glucanase activities of banana plants, and FOC populations as well as soil rhizosphere microbial community. Five fertilization treatments were considered, including chemical fertilizer containing the same N, P and K concentrations as the BIO(control), and matured compost mixed with antagonists Paenibacillus polymyxa SQR-21 and Trichoderma harzianum T37(BIO1), Bacillus amyloliquefaciens N6(BIO2), Bacillus subtilis N11(BIO3), and the combination of N6 and N11(BIO4). The results indicated that the application of BIOs significantly decreased the incidence rate of Fusarium wilt by up to 80% compared with the control. BIOs also significantly promoted plant growth, and increased chitinase andβ-1,3-glucanase activities by 55%–65% and 17.3%–120.1%, respectively, in the banana roots. The population of FOC in the rhizosphere soil was decreased significantly to about 104 colony forming units g-1with treatment of BIOs. Serial dilution plating and denaturing gradient gel electrophoresis analysis revealed that the application of BIOs increased the densities of bacteria and actinomycetes but decreased the number of fungi in the rhizosphere soil. In general, the application of BIOs revealed a great potential for the control of Fusarium wilt disease of banana plants.     

淹水培养过程中水稻土地杆菌科微生物群落结构变化特征

采用淹水非种植水稻土微环境模式系统,对水稻土进行1 h和1、5、10、20、30 d淹水培养,利用PCR-DGGE技术检测、多元统计分析淹水培养过程中地杆菌科微生物的群落结构和多样性变化规律及其影响因子。结果表明,淹水培养过程中地杆菌科微生物群落结构发生了明显的演替性变化：由r-对策优势种群演替至k-对策优势种群,且群落结构由不稳定向稳定演变（培养1 h和1 d处理间相似性最低,群落结构变化最大,20 d和30 d处理间相似性最高,群落结构变化最小）;该过程中,地杆菌科微生物物种丰富度指数和Shannon-Weiner指数在1 h处理中均为最小,5 d处理的最大;CCA相关性分析表明,淹水培养过程中Fe（Ⅱ）浓度与群落结构多样性指数呈正相关,证实该类微生物对于异化铁还原能力具有重要作用;测序结果表明,19个优势DGGE条带与来自水稻土中的未培养地杆菌科微生物亲缘关系相近。