Some enzyme and respiratory activities of tropical soils from new hebrides

Activities of invertase and amylase and respiratory activities of samples of 11 soils from New Hebrides were determined. The soils mostly were under forest and were acid with medium to low C/N ratios. Invertase activities were rather low but amylase activities were similar to those found in New Zealand soils. The ratios of invertase to amylase activities were mostly low.O₂ uptakes mostly responded markedly to glucose. Most values of respiratory quotients were about 1.0. Most, but not all, dehydrogenase activities were strongly related to O₂ uptakes. On an organic C basis, these respiratory activities declined with the depths to which the soils were sampled.Biochemical activities were mostly similar in forest soils derived from basalt and from andesite. Invertase activities were lower in soils under forest than under grassland covers.All biochemical activities were correlated significantly with contents of soil moisture and organic C, less with numbers of aerobic bacteria, and negatively with soil pH. On an organic C basis, none of the biochemical activities was significantly correlated with either soil moisture content or pH.     

Multi-scale variability analysis reveals the importance of spatial distance in shaping Arctic soil microbial functional communities

Understanding biological diversity and distribution patterns at multiple spatial scales is a central issue in ecology. Here, we investigated the biogeographical patterns of microbial functional genes in 24 heath soils from across the Arctic using GeoChip-based metagenomics and principal coordinates of neighbour matrices (PCNM)-based analysis. Functional gene richness varied considerably among sites, while the proportions of each major functional gene category were evenly distributed. Functional gene composition varied significantly at most medium to large spatial scales, and the PCNM analyses indicated that 14–20% of the variation in total and major functional gene categories could be attributed primarily to relatively large-scale spatial effects that were consistent with broad-scale variation in soil pH and total nitrogen. The combination of variance partitioning and multi-scales analysis indicated that spatial distance effects accounted for 12% of the total variation in functional gene composition, whereas environmental factors accounted for only 3%. This small but significant influence of spatial variation in determining functional gene distributions contrasts sharply with typical microbial phylotype/species-based biogeographical patterns (including these same Arctic soil samples), which are primarily determined by contemporary environmental heterogeneities. Therefore, our results suggest that historical contingencies such as disturbance events, physical heterogeneities, community interactions or dispersal barriers that occurred in the past, have some significant influence on soil functional gene distribution patterns.     

不同母质类型水稻土酶活性及其与理化性质的关系

将选自湖南双季稻区6种典型成土母质发育的水稻土置于长沙市郊同一生态条件下,通过7年定位池栽试验,研究了不同母质类型对土壤酶活性的影响以及酶活性与土壤理化性质之间的关系。结果表明：不同母质类型对土壤蔗糖酶活性的影响达到显著水平(P<0.05),对酸性磷酸酶、脲酶及过氧化氢酶活性的影响达到极显著水平(P<0.01)。主成分分析表明不同母质发育的水稻土酸性磷酸酶及脲酶作为综合评价土壤酶活性的指标要优于蔗糖酶及过氧化氢酶。6种不同母质水稻土土壤酶综合得分排序为：板页岩>河流沉积物>花岗岩>第四纪红土>紫色页岩>石灰岩。相关性分析表明,土壤蔗糖酶活性与有机质、全氮含量呈显著的正相关关系(P<0.05)。脲酶活性与硝态氮、铵态氮含量呈显著的正相关关系(P<0.05),与pH值呈显著的负相关关系(P<0.05)。酸性磷酸酶活性与速效磷含量呈显著正相关关系(P<0.05),与pH值呈显著负相关关系(P<0.05)。     

绿肥对植烟土壤酶活性及土壤肥力的影响

通过田间试验,研究翻压绿肥对植烟土壤酶活性及土壤肥力的影响。结果表明, 翻压绿肥能够明显提高土壤酶活性和土壤肥力水平,当绿肥翻压量在15000 kg/hm2以上时,尤其在22500~30000 kg/hm2之间时对土壤各项指标的影响更加明显。与对照相比,翻压绿肥的各处理土壤脲酶、 酸性磷酸酶、 蔗糖酶、 过氧化氢酶增幅分别为13.10%2~3.81%、 12.92%~29.38%、 75.35%~234.51%、 29.17%~37.08%; 土壤有机质、 全氮、 碱解氮、 有效磷、 速效钾、 pH、 孔隙度增幅分别为13.01%~70.41%、 6.42%~27.52%、 1.14%~10.99%、 15.97%~34.99%、 10.28%~38.30%、 2.74%~7.05%、 0.19%~2.50%,土壤容重降幅为1.47%~5.15%。简单相关分析表明,脲酶、 酸性磷酸酶、 蔗糖酶、 过氧化氢酶4种酶之间以及4种酶与土壤理化因子之间均有极显著的相关关系,而土壤酶活性之间的相互关系表明,土壤酶在促进土壤有机物质转化中不仅显示其专性特性,同时也存在共性关系; 典型相关分析结果为,第一对典型变量线性函数反映了土壤酶活性和土壤养分因子对土壤综合肥力水平的影响,第二对典型变量线性函数反映了施入绿肥对土壤内部重要的生理生化过程变化的影响; 主成分分析结果显示,第一主成分反映了土壤的综合肥力水平,所有因子均对土壤肥力水平起到了正效应,土壤酶活性能够和土壤理化因子共同评价土壤综合肥力水平。以上结果说明,翻压绿肥后土壤生物过程活跃,有利于土壤有机物质的转化和烤烟正常生长所需的营养供应。     

土壤磁效应的研究

A study on the effect of applied magnetic field was performed with six types of soils collected from northeastern China.Magnetic field was found to cause changes of soil physico-chemical properties and soil enzyme activities.An appropriate applied magnetic field could cut down soil zeta-potential,soil specific surface,soil water potential and soil swelling capacity;raise the charge density on soil colloids and the activities of invertase,hydrogen peroxidase and amylase in the soils;enhance soil aggregation and improve soil structural status and soil water-releasing capability.     

用通径分析法研究土壤水解酶活性与土壤性质的关系

为正确评价土壤性质对酶活性的影响程度 ,运用通径分析方法研究了浙江 5种土壤 1 2个样品中的土壤脲酶、转化酶、酸性磷酸酶活性与土壤性质的关系。结果表明 :土壤有机质、全氮、全磷是制约脲酶、转化酶和酸性磷酸酶活性的主要因素 ,而阳离子交换量对三种酶活性的影响均很微弱 ;就通径分析的直接效应而言 ,pH对脲酶活性的影响最为显著 ,对转化酶和酸性磷酸酶活性的影响程度大致相当。然而pH对脲酶、转化酶、酸性磷酸酶的这种直接效应在很大程度上被通过其它因素对三种酶的间接效应所抵消 ;土壤粉粒对转化酶活性的作用尤为显著。此外 ,粘粒对酸性磷酸酶、砂粒对脲酶有一定影响且均主要体现为直接效应。     

AN ASSESSMENT OF THE RELATIONSHIP BETWEEN THE SURFACE PROPERTIES OF CHALK SOILS AND SLOPE FORM USING PRINCIPAL COMPONENTS ANALYSIS

Five line transects were sited over grass-covered, convex-concave slopes in the Berkshire and Wiltshire chalk downs, with the object of describing and interpreting the variation in selected surface soil properties. Previous work had concentrated upon the correlation between single variables and slope gradient and slope length, whereas the emphasis of the present paper lies in examining the interrelationships amongst the variables through the use of principal components analysis. A consistent pattern of variation was established between the five sites. The first component derived from the analysis was interpreted as a combined organic matter and soluble constituents factor, which accounted for between 50 and 60 per cent of the total variance. The second component was identified as particle-size variation and accounted for a further 13 to 18 per cent of the total variance. Whereas the distribution of the component scores for the second component supported the original idea of a sharp junction effect in the pattern of soil properties on the slope, the first and most important component indicated a more diffuse transition from net erosion to net deposition conditions.     

三峡库区不同林龄柑橘土壤酶活性的演变

土壤酶驱动土壤生态系统养分的循环和控制生态系统的功能。本研究以生长年限为10、20年和30年的柑橘林0~20 cm和20~40 cm土层土壤为研究对象,主要探讨了土壤脲酶、转化酶和过氧化氢酶活性随着柑橘林龄的延长和土壤深度的增加的变化规律。结果表明,随着柑橘林龄的延长,0~20 cm土层土壤过氧化氢酶活性10年和20年样地之间无显著性差异,但都显著大于30年的样地;而0~20 cm土层土壤转化酶和脲酶活性逐渐提高,20年时达到最大值,其后又降低。随着土壤深度的增加,过氧化氢酶、转化酶和脲酶活性在3个林龄的柑橘林中都呈现显著的下降趋势。相关性分析的结果表明,土壤转化酶活性、脲酶活性都与土壤有机碳和微生物量碳氮之间都具有显著的正相关性,而过氧化酶氢活性与土壤理化特性及其微生物量之间都无显著的相关性。主成分分析结果进一步显示,土壤转化酶活性、脲酶活性、有机碳和微生物生物量碳氮均在第一主成分中具有较大的载荷,对第一主成分的贡献最大。以上结果表明脲酶和转化酶活性能够做为柑橘土壤质量变化的敏感指标。     

生物质炭及过氧化钙对旱地红壤酶活性和微生物群落结构的影响

明确生物质炭等改良剂对土壤酶活性及土壤微生物群落结构的影响,对南方红壤旱地改良剂的合理施用及评价不同改良剂对旱地红壤肥力的影响具有重要意义。针对江西旱地红壤进行室内培养试验,试验设置4个处理,即CK、Ca(过氧化钙,1.72 g/kg)、C(生物质炭,21.46 g/kg)、C+Ca(过氧化钙,1.72 g/kg;生物质炭,21.46 g/kg),利用磷脂脂肪酸方法(PLFA),研究改良剂对土壤微生物量和组成以及土壤酶活性、土壤活性有机碳的影响。结果表明:旱地红壤中添加生物质炭和过氧化钙土壤提高可溶性有机碳(DOC)和微生物量碳(MBC)含量;增加蔗糖酶(INV)、淀粉酶(AMY)及脲酶(URE)活性,特别是配施(C+Ca)显著提高土壤活性碳含量及酶活性。PLFA分析表明,土壤微生物总PLFAs量的大小顺序为:C+CaCCaCK;各处理土壤细菌的相对丰度最大,大约占微生物总含量的80%,放线菌次之,大约占微生物总含量的13%～15%,而真菌和丛枝菌根真菌的相对丰度较低。生物质炭和过氧化钙增加了革兰氏阴性菌(GN)/革兰氏阳性菌(GP)值,尤以C+Ca处理增加幅度最大。主成分分析(PCA)表明,添加生物质炭和过氧化钙能够改善土壤微生物群落结构;计算主成分的综合得分,配施(C+Ca)处理的综合得分最高,对土壤微生物群落结构的影响最大。冗余分析(RDA)表明,土壤MBC、DOC和土壤INV酶活性是影响土壤微生物数量和结构的主要因子。因此,施用生物质炭和过氧化钙能够明显提高旱地红壤微生物生物量,改变红壤微生物群落结构以及激发红壤酶活性,且配施效果最显著。     

长期施用畜禽粪便对土壤生物化学质量指标的影响

采用两种母质发育的,长期施用畜禽粪便和化肥的稻麦轮作土壤作为供试土壤,探讨了施用畜禽粪便对土壤微生物组成、微生物生物量及活性、土壤酶活性等生物化学质量指标的影响。研究结果显示,与施用化肥比较,长期施用畜禽粪便显著提高了土壤细菌和放线菌数量(+72%和+132%)、土壤微生物生物量碳、氮(+89%和+74%)、土壤基础呼吸速率和微生物商(+49%和+45%),但降低了土壤真菌的数量(-38%)。土壤脲酶和转化酶活性也表现为长期施用畜禽粪便土壤高于施用化肥土壤。由于受土壤pH值强烈影响,土壤微生物代谢商(qCO2)和土壤磷酸酶活性没有表现出明显的变化规律。回归分析结果显示,长期施用畜禽粪便改变土壤活性有机碳含量和理化性质是导致土壤生物化学质量指标变化的主要原因。     

主成分分析方法在长期施肥土壤质量评价中的应用

以长期定位试验玉米季成熟期6种土壤微生物活性和9种土壤化学性质指标组成的土壤生物肥力性质为评价指标对不同施肥条件下的土壤质量水平进行主成分分析。结果表明,经18年连续不同施肥处理后,各土壤性质在处理间均产生显著差异,但各土壤性质在处理间的变化趋势并不完全一致。上述15个土壤性质指标最终可以用两个主成分来综合表征土壤质量,其中有机C、全N、碱解N、pH值、微生物生物量C、微生物生物量N、脲酶、转化酶、FDA酶和脱氢酶活性等10个土壤性质在第一主成分（PC1）上有较高因子负荷;全P、全K、速效N和速效P在第二主成分（PC2）上有较高的因子负荷。同时各施肥土壤质量水平在主成分1上的分异程度大于主成分2。根据两个主成分的综合得分结果显示,长期不同施肥土壤质量水平高低依次表现为OM＞1/2OM＞NPK＞NP＞PK＞NK＞CK。     

城郊结合区蔬菜种植地土壤性质特征

Human activity and urbanization result in urban-rural environmental gradients.Undersanding effect of the gradients on soil properties is necessary for management of the soils around urban areas.In this study,soil quality of some vegetable fields was characterized along an urban-rural gradient in shaoxing County,Zhejiang Province.Fifteen soilphysical and chemical properties were evaluated by using principal component analysis.Results showed that there was a great variation in the soil quality along the gradient.From rural to urban zones,soil organic matter,water-stable aggregates,cation exchangeable capacity(CEC),total N and P,and available K increased,whereas soil pH value decreased.In addition,Pb,Cu,Ni,Co,Zn and Cr in the soils tended to be accumulated toward the urban zone.Sequential chemical extraction showed that mobility of all the heavy metals in the soils tended toincrease from the rural to the urban zones.The variation of soil properties accounted for by the first principal component was significantly explained bythe difference in application rates of municipal wastes.     

接种含ACC脱氨酶的假单胞菌能部分缓解干旱胁迫对豌豆生长、产量及成熟的影响

Two preselected plant growth promoting rhizobacteria （PGPR） containing 1-aminocyclopropane-1-carboxylate （ACC）- deaminase （EC 4.1.99.4） were used to investigate their potential to ameliorate the effects of drought stress on growth, yield, and ripening of pea （Pisum sativum L.）. Inoculated and uninoculated （control） seeds of pea cultivar 2000 were sown in pots （four seeds pot-1） and placed in a wire house. The plants were exposed to drought stress at different stages of growth （vegetative, flowering, and pod formation） by skipping the respective irrigation. Results revealed that inoculation of peas with PGPR containing ACC-deaminase significantly decreased the ＂drought stress imposed effects＂ on the growth and yield of peas. Exposure of plants to drought stress at vegetative growth stage significantly decreased shoot growth by 41% in the case of uninoculated plants, whereas, by only 18% in the case of inoculated plants compared to nonstressed uninoculated control.
Grain yield was decreased when plants were exposed to drought stress at the flowering and pod formation stage, but inoculation resulted in better grain yield （up to 62% and 40% higher, respectively） than the respective uninoculated nonstressed control. Ripening of pods was also delayed in plants inoculated with PGPR, which may imply decreased endogenous ethylene production in inoculated plants. This premise is further supported by the observation that inoculation with PGPR reduced the intensity of classical ＂triple＂ response in etiolated pea seedlings, caused by externally applied ACC. It is very probable that the drought stress induced inhibitory effects of ethylene could be partially or completely eliminated by inoculation with PGPR containing ACC-deaminase.     

Biochemical properties in managed grassland soils in a temperate humid zone: modifications of soil quality as a consequence of intensive grassland use

Although soil biochemical properties are considered to be good indicators of changes in soil quality, few studies have been made of the changes in biochemical properties brought about by anthropogenic disturbance of grassland ecosystems. In the present study, several biochemical properties were analysed in 31 grassland soils subjected to a high level of management, and the values obtained were compared with known values corresponding to native grasslands from the same region (Galicia, NW Spain). The 31 managed grasslands were divided into two groups (re-sown grasslands and improved grasslands) according to their management and past land use. The biochemical properties studied were: labile carbon, microbial biomass carbon, microbial respiration, metabolic quotient, net nitrogen mineralisation and the activities of dehydrogenase, catalase, phosphodiesterase, phosphomonoesterase, casein hydrolysing proteases, benzoyl arginamide (BAA)-hydrolysing proteases, urease, cellulase, ß-glucosidase, invertase and arylsulphatase. Managed grasslands exhibited lower values of soil biochemical properties than native grasslands. Three biochemical equilibrium equations were used to compare soil quality in managed and native grasslands. One of the equations did not show any significant difference between the groups of grassland soils considered. In contrast, two of the equations showed similar soil quality for improved and native grasslands, while re-sown grasslands exhibited a loss of soil quality when compared to native grassland soils.     

覆膜滴灌对地下水浅埋区重度盐碱地土壤酶活性的影响

为了解地下水浅埋区重度盐碱地覆膜滴灌对土壤酶活性的影响,测定了重度盐碱地在滴灌利用过程中距离滴头不同水平位置（0～30 cm）和垂直深度（0～40 cm）的土壤碱性磷酸酶、脲酶和蔗糖酶活性,并对土壤酶活性的变化、空间分布特征及与土壤环境因子之间的相关关系进行分析。结果表明,覆膜滴灌促进了土壤酶活性的提高;水平与垂直方向滴头附近3种酶均易受覆膜滴灌作用影响,灌溉期间酶活性的增长与停灌期间酶活性降低均高于其他位置;土壤酶活性自滴头向四周径向减小,等值线呈椭圆形分布;相关分析表明盐碱土壤在覆膜滴灌种植2 a后,土壤酶活性与环境因子、土壤酶活性之间的相关性均得到提高。因此,将覆膜滴灌技术应用于盐碱地开发利用可以提高土壤酶活性,改善土壤环境,为作物根系提供良好的生长条件。     

Invertase and amylase activities in ryegrass and white clover plants and their relationships with activities in soils under pasture

Invertase and amylase activities were determined in the herbage and roots of ryegrass and white clover grown under aseptic and field conditions, and in the herbage, litter, roots, and soil of three grass-legume pastures. These activities were appreciably greater in all plant materials than in soil, on either a dry weight or an organic C basis. Invertase-amylase activity ratios in plant materials and in soil were not directly related at the three pasture sites. The activities of aseptically grown plants were not consistently influenced by harvest conditions under light or darkness. They did differ in different tissues and plant species, with amylase activity greatest in white clover. Plant roots did not appear to excrete enzymes with these activities.Chromatographic data suggest that β-amylases contributed most to the amylase activity of herbage and roots, whereas α-amylases and possibly other hydrolytic enzymes, were most important in litter and soil. Other evidence suggests that β-amylases, as well as α-amylases, would also have been active in the soils.Under field conditions, the invertase and amylase activities of the herbage and roots appear to be due mainly to plant-derived enzymes, rather than to associated micro-organisms. In the soils, microorganisms and plants appear to contribute to these activities.     

广西平果县岩溶山地不同植物群落的土壤酶活性

为探讨平果县岩溶山地典型植物群落的土壤酶活性特征,基于调查取样与试验分析,采用相关分析、多重比较以及主成分分析方法,研究了不同植物群落间土壤酶活性的差异,分析了土壤酶活性与土壤化学性质的关系。结果表明:(1)土壤过氧化氢酶、脲酶及蔗糖酶活性的群落间差异达显著水平,显示不同植物群落对土壤酶活性产生一定影响;(2)土壤pH值与过氧化氢酶、脲酶间呈极显著正相关(p0.01),与碱性磷酸酶间呈显著负相关(p0.05);(3)4个酶活性与代表土壤肥力的土壤有机质、全氮、全磷、全钾、碱解氮及速效钾之间具有较强的相关性,但速效磷与4个土壤酶之间的相关性均未达显著水平(p0.05);(4)过氧化氢酶、脲酶及碱性磷酸酶能敏感反映土壤质量的变化,可作为本区域土壤质量评价的指标。     

Effect of management and climate on biochemical properties of grassland soils from Galicia (NW Spain)

Biochemical properties are considered to be the best indicators available at present for assessing soil quality. However, there are still many gaps in our knowledge about how these properties are affected by abiotic factors and how these factors interact with soil management. With the aim of understanding how climate and soil management affect soil biochemical properties in grasslands soils from a temperate-humid area (Galicia, NW Spain), a total of 60 soils were analyzed for several microbial and biochemical properties. Grasslands were divided into groups according to the type of management applied (native compared with intensive) and to the climate in the area where they were sampled (Mediterranean subhumid with centroeuropean drift climate compared with Atlantic climate). We found that management had a greater influence on soil biochemical properties than climate. Altitude, which strongly influences climate in the region where the soils were analyzed, was found to be a significant factor that affected most soil biochemical properties. In conclusion, the results show that microbially-mediated processes are greatly affected by both, management and abiotic factors and that, for some properties (like net N mineralization and cellulase and casein-protease activities), abiotic factors can have an important influence on soil biochemical properties.     

砂姜黑土中重金属Cu、Cd、Zn形态分布与土壤酶活性研究

采用小麦农田取样,对土壤中的重金属运用连续提取方法,研究了皖北砂姜黑土中Cu、Cd、Zn的化学形态特征及其与四种土壤酶(过氧化氢酶、脲酶、蔗糖酶、中性磷酸酶)活性间的关系。结果表明:在砂姜黑土中,残留态Cu、Cd、Zn在总量中所占比例很高,交换态、有机态、碳酸盐结合态含量明显低于残留态。在三种元素中,Zn的化学形态变化趋势最为一致,表现为残留态>碳酸盐结合态>铁锰结合态>有机态>交换态;砂姜黑土中交换态Cu、Cd、Zn对脲酶活性有显著抑制作用,有机态Cu、Cd、Zn对过氧化氢酶表现为一定程度的促进作用。因此,在砂姜黑土壤中,把交换态Cu、Cd、Zn和脲酶以及中性磷酸酶的活性共同作为评价土壤Cu、Cd、Zn污染程度的主要生化指标是可行的。     

Biomass and Phosphorus Uptake Responses of Maize to Phosphorus Application in Three Acid Soils from Southern Cameroon

Abstract

A phosphorus (P) greenhouse experiment was carried out with maize (Zea Mays L.) using surface horizons of three contrasted acid soils from southern Cameroon. The objectives were (i) to assess causal factors of maize differential growth and P uptake and (ii) to explore plant–soil interactions in acid soils under increasing P supply. Shoot and root dry‐matter yield and P uptake were significantly influenced by soil type and P rate (P<0.000), but the interaction was not significant. Soil properties that significantly (P<0.05) influenced maize growth variables were available P, soil pH, exchangeable bases [calcium (Ca), magnesium (Mg)], and exchangeable aluminium (Al). Data ordination through principal‐component analysis highlighted a four‐component model that accounted for 88.1% of total system variance (TSV) and summarized plant reaction in acid soil condition. The first component, associated with 36.1% of TSV, pointed at increasing root–shoot ratio with increasing soil acidity and exchangeable Al. The second component (24.6% of TSV) highlighted soil labile P pool increase as a function of P rate. The third and fourth components reflected nitrogen (N) accumulation in soils and soil texture variability, respectively.