尿素施用量对道地药材滁菊土壤微生物活性的影响

通过田间试验,研究不同尿素施用量对道地药材滁菊土壤微生物数量、土壤酶活性和土壤微生物量碳、氮和产量的影响。结果表明,随着尿素施用量的提高,土壤细菌、真菌、放线菌和土壤过氧化氢酶、蛋白酶、脲酶呈先增加后降低的变化趋势,以N1（225kg N/hm2）或N2（450kg N/hm2）处理的酶活性较高,N3（675kg N/hm2）处理的酶活性略有降低;磷酸酶活性则呈上升趋势,以N3（675kg N/hm2）处理的脲酶活性最大。就土壤微生物量而言,土壤微生物C和土壤微生物N随施氮量的增加呈先增加后降低的趋势,尤其以土壤微生物N变化较为明显。表明适宜尿素施用量有益于滁菊根际微生物酶活性和土壤微生物量的提高,施用量过高则微生物量和酶活性下降。     

宁南黄土丘陵区马铃薯连作土壤养分、酶活性和微生物区系的演变

采用常规方法研究了宁南黄土丘陵区马铃薯不同连作年限土壤养分、酶活性及微生物区系组成的演变趋势。结果表明,宁南黄土丘陵区土壤有机质及全氮与土壤微生物数量和酶活性均呈显著正相关;马铃薯连作4年引起土壤有机质、全氮、全磷及全盐含量显著下降,而土壤pH、磷酸酶和过氧化氢酶活性显著增加;试验区土壤微生物区系组成中细菌占微生物总量的80%以上;随连作年限的延长,土壤真菌比例逐渐上升,土壤放线菌比例有较大幅度提高,而土壤细菌比例则明显下降。逐步回归分析表明,脲酶、蔗糖酶、真菌、放线菌和细菌都与土壤有机质、全氮及速效氮显著正相关,与过氧化氢酶活性显著负相关;全磷及速效磷只和磷酸酶极显著正相关;土壤pH与脲酶、蔗糖酶及细菌均呈显著或极显著负相关;脲酶与蔗糖酶及细菌、放线菌和真菌之间均呈显著或极显著正相关,与过氧化氢酶极显著负相关。马铃薯连作不仅加重土壤养分亏缺,土壤理化性状恶化,而且导致过氧化氢酶活性显著增加,土壤微生物区系组成发生改变。     

氮素和水分对贝加尔针茅草原土壤酶活性和微生物量碳氮的影响

在内蒙古贝加尔针茅草原,分别设对照(N0)、1.5 g·m-2(N15)、3.0 g·m-2(N30)、5.0 g·m-2(N50)、10.0 g·m-2(N100)、15.0 g·m-2(N150)、20.0 g·m-2(N200)和30g·m-2(N300)(不包括大气沉降的氮量)8个氮素(NH4NO3)梯度和模拟夏季增加降水100 mm的水分添加交互试验,研究氮素和水分添加对草原土壤养分、酶活性及微生物量碳氮的影响。结果表明:氮素和水分添加对草原土壤理化性质和生物学特性有显著影响。随施氮量的增加土壤总有机碳、全氮、硝态氮、铵态氮含量呈增加的趋势,相反,土壤pH值呈降低的趋势。土壤脲酶和过氧化氢酶的活性随施氮量的增加而升高,多酚氧化酶则随施氮量的增加呈下降的趋势。氮素和水分添加对草原土壤微生物量碳氮含量有显著影响,高氮处理(N150、N200和N300)显著降低了微生物碳含量,微生物氮含量随施氮量的增加呈上升趋势。水分添加能够减缓氮素添加对微生物的抑制作用,提高微生物量碳、微生物量氮含量。草原土壤养分、土壤酶活性及土壤微生物量碳氮含量间关系密切,过氧化氢酶与全氮、总有机碳、硝态氮呈显著正相关,多酚氧化酶与铵态氮、硝态氮、全氮呈显著负相关。微生物量氮含量与土壤全氮、铵态氮、硝态氮含量以及过氧化氢酶和磷酸酶活性呈显著正相关,与多酚氧化酶呈负相关;微生物量碳与过氧化氢酶呈负相关,与多酚氧化酶活性呈正相关。     

基于旋耕玉米秸秆还田条件下土壤微生物、酶及速效养分的动态特征

为研究旋耕条件下秸秆还田的腐解机理,设置不同数量秸秆还田处理,分别于玉米拔节期、抽雄期、乳熟中期、完熟期测定土壤微生物数量、土壤酶活性和速效养分含量。结果表明:(1)秸秆还田促进土壤微生物繁殖,提高土壤酶活性,增加碱解氮含量,降低速效磷和速效钾含量;秸秆量为11 250kg/hm~2时真菌、细菌、放线菌数量及蔗糖酶、纤维素酶活性增幅最大;秸秆量为7 500kg/hm~2时脲酶、磷酸酶活性和碱解氮增幅最大,速效磷、速效钾降幅最大。(2)部分土壤微生物数量与土壤酶活性之间存在相关性,播种后40天,土壤真菌、细菌、放线菌数量、纤维素酶活性之间存在正相关,真菌与磷酸酶活性呈负相关;播种后67天,放线菌与磷酸酶、蔗糖酶呈正相关;播种后140天,放线菌与蔗糖酶呈正相关。(3)部分土壤酶活性之间存在相关性,播种后67天,脲酶与纤维素酶、磷酸酶与蔗糖酶之间呈正相关;播种后140天,蔗糖酶与纤维素酶呈正相关,脲酶与蔗糖酶、纤维素酶呈负相关。(4)土壤酶活性与速效养分存在相关性,播种后40,112天的脲酶、67天的纤维素酶、112,140天的磷酸酶与碱解氮含量呈正相关;播种后40天,蔗糖酶与速效钾呈正相关,播种后40,67,112天脲酶活性与速效钾含量呈负相关。(5)碱解氮与速效磷含量呈负相关,播种后40,112,140天的碱解氮与速效钾含量呈负相关。     

不同施肥措施对春玉米农田土壤酶活性的影响

为研究肥料配比对春玉米农田土壤酶活性的影响,连续4年采用田间定位种植春玉米,分析各生育期各土层酶活性,利用聚类分析和主成分分析揭示酶活性的动态变化差异。结果表明,各种施肥措施显著增加蔗糖酶、脲酶和磷酸酶活性,主要影响10~20 cm土层酶活性。施用有机肥土壤酶活性最大值出现在散粉期,施用无机肥土壤酶活性最大值出现在大喇叭口期。随着土层深度的增加,蔗糖酶、脲酶、磷酸酶活性呈下降趋势;过氧化氢酶活性10~20 cm土层最低。配合施肥中增施氮肥降低过氧化氢酶活性,增加蔗糖酶、脲酶活性;增施磷肥增加脲酶、磷酸酶活性;增施有机肥增加过氧化氢酶活性,降低蔗糖酶、脲酶活性。单施氮肥降低土壤脲酶和磷酸酶活性。有机无机肥配施能够延长春玉米生育期土壤酶活性的高值期。土壤蔗糖酶、脲酶、过氧化氢酶和磷酸酶活性分别受全钾、全氮、有机质和全氮、全磷和有机质含量的影响,施肥通过改变土壤元素含量及供给能力影响土壤酶活性。     

不同形态氮素对种植大豆土壤中微生物数量及酶活性的影响

采用框栽试验方法,研究6种不同形态氮素[生物固氮(N0)、硝态氮(N1)、铵态氮(N2)、氨基酸态氮(N3)、蛋白态氮(N4)和酰胺态氮(N5)]对种植大豆土壤中微生物数量及土壤酶活性动态变化的影响。结果表明:各大豆生育期内真菌、细菌、放线菌数量和土壤脲酶、蔗糖酶活性对不同形态氮素的反应不同;三大菌群在组成上以细菌数量占绝对优势,数量上均在花期时达到峰值,即均随着大豆生育期的推进呈单峰曲线变化;花期不同形态氮处理下的土壤微生物总数量有差异,具体表现为N5N3N2N1N4N0。土壤多样性指数的变化趋势随着生育期的推进呈缓慢下降趋势,与土壤微生物数量的变化趋势不一致,因此,评价土壤生物多样性指数应将两者结合起来。土壤脲酶和蔗糖酶活性随着生育期的推进亦为单峰曲线变化趋势,但脲酶与蔗糖酶活性的变化趋势不同,其高峰期出现在鼓粒期。     

退化生态系统植被恢复过程中土壤微生物群落活性响应

通过分析退化生态系统中主要植被恢复类型对土壤微生物群落活性的影响,探讨敏感和可靠的微生物群落活性响应指标,揭示适合当地生态条件的植被恢复类型。结果表明,沙米荒地、白沙蒿、柠条、沙冬青和人工乔木林地土壤微生物量C,N,P和微生物商、蔗糖酶、脲酶、过氧化氢酶、碱性磷酸酶均表现出显著差异(P<0.05)。在土壤各层内,除上层人工乔木林地土壤微生物量N相对较高外,柠条恢复草地土壤微生物量C,N,P都相对较高,沙米荒地均较低;土壤微生物商没有明显的趋势;人工乔木林地蔗糖酶和柠条恢复草地脲酶活性相对较高,过氧化氢酶和碱性磷酸酶活性没有明显的变化趋势,沙米荒地的蔗糖酶、脲酶和过氧化氢酶活性以及白沙蒿草地碱性磷酸酶活性较低。方差分析(ANOVA)显示,蔗糖酶、脲酶、过氧化氢酶和碱性磷酸酶与土壤有机质、全氮以及微生物量C,N,P之间呈显著相关关系;主成分分析(PCA)表明,土壤微生物量N,C,P和蔗糖酶、土壤微生物商基本反映了研究区植被恢复中土壤微生物群落活性的响应信息。不同植被恢复类型草地中土壤微生物群落活性的变化表明,柠条和人工乔木林是研究区域内适合当地生态条件的植被恢复类型。     

不同种养废弃物还田对复垦宅基地土壤酶活性和微生物数量的影响

以成都平原复垦宅基地土壤为对象,研究3类种养废弃物(秸秆、猪粪和菌渣)与化肥配施下土壤酶活性、微生物数量的动态变化及其相关性。结果表明:(1)3类"种养废弃物+化肥"配施相比空白(CK)和常规施肥(CF)方式,均能显著提高复垦宅基地土壤微生物数量和土壤酶活性。(2)小麦成熟期,0—20,20—40cm土层土壤微生物总数分别在猪粪还田(MCF)和菌渣还田(FCF)下达到最大值26.89×10~6 cfu/g和17.82×10~6 cfu/g。MCF和FCF处理下3种微生物(细菌、真菌和放线菌)数量都显著高于SCF处理,但MCF和FCF处理之间基本无显著差异。(3)归一化的土壤酶活性值除在0—20cm土层MCF处理达到最高值0.140外,其余均在FCF处理下达到最大。在小麦成熟期,土壤脲酶、蔗糖酶和过氧化氢酶活性基本呈现出FCFSCFMCF的规律(除0—20cm土层土壤脲酶)。(4)5种处理下的土壤酶活性、微生物数量、土壤有机碳及全氮之间均表现出显著相关。(5)0—20cm土层种养废弃物配施处理下微生物数量、脲酶及蔗糖酶活性在小麦生育期内呈倒"U"型变化趋势,过氧化氢酶活性呈不断上升的趋势;20—40cm土层微生物数量和土壤酶活大致呈递增趋势。(6)综合分析表明,"菌渣+化肥"配施处理(FCF)为成都平原复垦宅基地土壤培肥较适宜方式。     

有机无机肥配施对湖南省晚稻生长、产量及土壤生物学特性的影响

在施肥按照全N 180 kg·hm-2、K2O 120 kg·hm-2、P2O5不低于90 kg·hm-2的条件下,研究了有机与无机肥的不同比例配施对水稻生长、产量、土壤微生物数量和酶活性的影响。结果表明,当季有机无机肥中的氮素比例为3∶7(T3)时,其理论产量和实际产量都最大,并显著高于其他处理,相比全施化肥的处理(T1),其理论产量提高了27.71%,实际产量提高了14.67%;其微生物(细菌、真菌和放线菌)数量除了分蘖期的细菌和真菌外都显著高于其他处理;其水稻成熟期的土壤过氧化氢酶活性、脲酶活性和蔗糖酶活性最大,并显著高于其他处理。因此,在一定的施肥条件下,有机无机肥的合理配施,可以显著增加水稻的产量,增加土壤微生物数量,提高土壤酶活性,达到培肥的目的。     

紫云英还田量对烟田土壤微生物及酶的影响

为在翻耕条件下合理施用紫云英,保障农业的可持续性发展,定位试验研究了15000kg·hm-2、22500kg·hm-2、30000kg·hm-2紫云英还田和22500kg·hm-2紫云英还田减施化肥(施肥时扣除紫云英中氮、磷、钾)及紫云英不还田5个处理对烟田土壤微生物数量、微生物活度、酶的影响。结果表明:烟草生育期内,不同处理好气性细菌数量呈前期均迅速上升、中期均稍有上升,但后期各有升降的趋势;烟草生长早期,紫云英还田减施化肥能增加好气性细菌数量。放线菌数量烟草生育前期略有下降,中期有所回升,后期又缓慢下降;烟草生长早期,紫云英还田能增加放线菌数量;整个烟草生育期,紫云英还田减施化肥可减少放线菌数量。真菌呈现烟草生育前中期迅速上升,后期缓慢下降的趋势;相对较少的紫云英还田量对土壤真菌数量增长的刺激作用较为明显。微生物活度呈烟草生育前期下降、中期趋于平稳、后期迅速升高达到最高点的趋势;烟草成熟期,紫云英还田的微生物活度明显高于不还田处理,增加紫云英还田量,微生物活度增加,但紫云英还田减施化肥会降低微生物活度。土壤纤维素酶活性以烟草旺长期为界点,表现出前期增加、后期下降的特点;烟草生长后期,紫云英还田土壤的纤维素酶活性高于对照土壤。土壤脲酶活性呈先快速下降,再缓慢上升,最后再快速上升趋势。土壤蛋白酶活性呈烟草生育前期下降,后期缓慢上升的特点;土壤蛋白酶活性与紫云英施用量呈正相关。过氧化氢酶活性在烟草各生育期的变化不大。土壤生物学评价发现,22500kg·hm-2紫云英翻耕还田栽培烟草较佳。     

Effect of soil acidification on the soil microflora

The effects of short and long term acidification on a few Alberta soils were studied with respect to bacterial numbers and total soil respiration. Significant reductions in bacterial numbers were observed in both short and long term acidified soils. Total soil activity was severely affected in an acid soil (pH 3.0, longterm) adjacent to a S block. A soil (pH 6.8) 200 m away from this S block when artificially acidified to pH 2.9 significantly reduced soil activity but not as drastically as found in the long term pH 3.0 soil. A garden soil (pH 7.7) which was also acidified to pH 3.2 showed no significant reduction in total soil respiration rate as compared to its unacidified control soil. These acid soils when amended with organic substrates demonstrated that certain physiological groups of organisms were severely inhibited by this acid condition. The importance of examining more than one parameter when assessing the effect of a potential pollutant on soil activity is discussed.     

红壤调理剂的改土培肥及作物增产研究

在南方红壤地区,土壤酸化加剧、养分贫瘠化严重,研发红壤改良的技术和物化产品,对作物均衡增产和红壤可持续利用有重要意义。红壤旱地连续3年定位种植油菜-花生,花生品种为赣花5号,油菜品种为丰油730。调理剂为自行研制的专利产品,已经实现了产业化。研究了红壤调理剂对土壤微结构、物理性状、养分和pH值的影响,并对花生、油菜的产量进行了分析。结果表明:1)施用调理剂后,从微观结构来看,红壤的致密性降低、孔隙度增加,土壤颗粒直径4μm;2)施用调理剂的土壤容重显著降低,孔隙度增加到59%以上,大颗粒水稳性团聚体(0.25 mm)含量增加幅度为1.6%~14.0%,分形维数显著降低,并且与0.25mm粒径的团粒结构含量间呈极显著线性相关;3)施用调理剂的土壤电导率、有机碳、矿质态氮、有效磷、速效钾含量均提高,提高幅度在4.3%~143.7%之间;4)施用调理剂还降低了红壤的酸性,pH值从对照处理的5.28提高到5.82,差异显著;5)施用调理剂,花生和油菜增产幅度分别在13.1%~24.8%、10.3%~21.6%之间;6)应用笔者研制的红壤调理剂,可有效改善红壤旱地的理化性质,提高油菜和花生产量,其用量在2 250~3 000 kg/hm~2时较佳。     

Assessment the effect of homogenized soil on soil hydraulic properties and soil water transport

Soil hydraulic properties play a crucial role in simulating water flow and contaminant transport. Soil hydraulic properties are commonly measured using homogenized soil samples. However, soil structure has a significant effect on the soil ability to retain and to conduct water, particularly in aggregated soils. In order to determine the effect of soil homogenization on soil hydraulic properties and soil water transport, undisturbed soil samples were carefully collected. Five different soil structures were identified: Angular-blocky, Crumble, Angular-blocky (different soil texture), Granular, and subangular-blocky. The soil hydraulic properties were determined for undisturbed and homogenized soil samples for each soil structure. The soil hydraulic properties were used to model soil water transport using HYDRUS-1D.The homogenized soil samples showed a significant increase in wide pores (wCP) and a decrease in narrow pores (nCP). The wCP increased by 95.6, 141.2, 391.6, 3.9, 261.3%, and nCP decreased by 69.5, 10.5, 33.8, 72.7, and 39.3% for homogenized soil samples compared to undisturbed soil samples. The soil water retention curves exhibited a significant decrease in water holding capacity for homogenized soil samples compared with the undisturbed soil samples. The homogenized soil samples showed also a decrease in soil hydraulic conductivity. The simulated results showed that water movement and distribution were affected by soil homogenizing. Moreover, soil homogenizing affected soil hydraulic properties and soil water transport. However, field studies are being needed to find the effect of these differences on water, chemical, and pollutant transport under several scenarios.     

Revised soil parameter estimates for the soil types of the world

Abstract. A revised set of physical and chemical parameter estimates is presented for the soil units of the world, as described by the two FAO soil legends (version 1974 and 1988). The study is based on 9607 soil profiles, which include profiles held in version 1.0 of the WISE database. Upon a screening of data integrity and comparability of analytical methods, derived statistics were generated for 28 soil chemical and physical attributes identified as being useful for assessment of land suitability, crop growth simulation datasets, and analyses of global environmental change.     

增加土壤渗透,减少水土流失

黄河会不会变清,什么时候能变清,关键就在于降雨能否渗入土层,渗入多少,何时实现。研究表明,黄河水流的透明度,与黄土层的入渗率成正相关。增加土壤渗透力的措施,主要有改变土壤质地,减小土壤容重,改良土壤结构和提高地面覆被率,特别是种植豆科牧草,效果更好。各种水土保持措施,旨在增加土壤渗透力,最大限度地减少水土流失,使全部地面径流变为涓涓沟泉,则黄河清澈见底。     

Effects of soil erosion on long-term soil productivity in the black soil region of northeastern China

China's northeastern Black Soil Region, one of the country's most important crop production areas, has been seriously affected by soil erosion. This study evaluated the effects of soil erosion on the long-term productivity of this region. We used a modified productivity index (MPI) model (MPI is a number between 0 and 1, with 1 indicating highest productivity) to assess the current effects of soil erosion on soil productivity, as well as to predict long-term change in productivity. Samples from 21 black soil profiles yielded varying MPI values, although most MPI values were indicative of moderate productivity. Organic matter content and available water capacity impact MPI values in the region, whereas soil clay content and pH were less important. Overall, organic matter content and available water capacity of soil profiles decreased consistently as depth of erosion increased. Modeling indicated that MPI in the region will decrease by 0.0052 for each centimeter of topsoil eroded; this rate represents 1% of the current average MPI for the study area. The model predicts a 9.6% productivity reduction over 100 years and a 48.3% reduction over 500 years.     

Effect of soil components on the surfactant-enhanced soil sorption of PAHs

Purpose  

The use of cationic surfactants was proposed to enhance the soil retention of hydrophobic organic contaminants (HOCs). However, due to the complexity of soil composition, the effect of cationic surfactants on the soil sorption of HOCs was limited to a qualitative understanding. To gain further insight into the mechanism of the surfactant and predict its efficiency, a comparative study on the HOCs sorption capacities of the surfactants sorbed on pure typical soil components was investigated.     

Mathematical modeling of the processes of soil deformation and soil compaction

The regularities of the dynamic deformation of soils with viscoelastic properties have been studied. The methods to calculate soil rheological parameters, the stress state of deformed soils, and soil compaction upon a gradual increase in pressure loads and upon cyclic sinusoidal loads created by consecutive passage of a rolling cylinder over the soil surface are suggested. The corresponding parameters have been calculated for soddy-podzolic and chernozemic soils. The quantitative assessment of the effect of a number of factors on changes in the bulk density and in the rheological properties of the soil at different depths upon the soil deformation is given.     

湘南红壤地区土壤肥力现状及其退化原因

调查结果表明：土壤的肥力已经出现了较为明显的退化现象,如果用土壤养分含量的结果来表示,则有５０％以上出现了肥力退化;如以产量为标准来衡量,则有２５％～３０％出现了退化。其主要表现是：部分土壤酸化;有机质、氮、磷、钾等养分的含量下降。退化的主要原因是施肥结构的无机化趋势上升以及氮、磷、钾化肥的施用比例失调,因此,调整目前不合理的施肥结构和施肥比例,是防止该地区土壤肥力进一步退化的当务之急。     

Influence of soil factors on the soil enzyme inhibition by Cd

A comparative study was conducted on the toxicity of Cd to alkaline phosphatase activity (ALP) and dehydrogenase activity (DHA) in 18 top soils with contrasting soil properties representative of 14 major soil types in China. Soil pH and carbonate content, soil organic matter, and cation exchange capacity (CEC) largely affected the Cd toxicity on two enzyme activities; with the soil pH having only minor effect on the median ecological dose values based on total Cd concentrations (ED_{50 T}). The values of ED_{50 T}/ED_{50 W} (based on water-soluble Cd content) of alkaline phosphatase and dehydrogenase were strongly influenced by pH and CEC contents, which explained up to 71% of the variation for alkaline phosphatase, 82% of the variation for dehydrogenase, and also were significantly correlated with the parameter K_F derived from Freundlich adsorption isotherms. This study suggests that the values of ED_{50 T}/ED_{50 W} could be useful to evaluate the buffer capacity of soils which protects soil enzymes from harmful effects of heavy metal.