The effect of some soil amendments on chemical and microbiological properties of an alkali soil

Summary A representative alkali soil sample from Tal-El-Kebir was treated in pots with different rates of gypsum or sulphur. These amounts were calculated according to the exchangeable sodium present in the soil. Chemical and microbiological properties were studied during reclamation process.Addition of gypsum in appropriate amounts to replace exchangeable sodium on the clay complex is much faster and more superior to the addition of the corresponding amounts of sulphur.Counts of total microbial flora, Azotobacter, nitrifiers, and aerobic cellulose-decomposers increased as the reclamation proceeded, on the other hand, counts of spores of aerobic sporeformers, streptomyces, and clostridia decreased.Cultivation of such reclaimed soils exerted beneficial effect on its microbial flora. Plant vigor which was taken as a resultant of the improvement of the physico-chemical and biological properties of the soil due to reclamation was found to be superior in case of addition of an amount of gypsum equivalent to the amount of adsorbed sodium.     

Ammonification in soil aggregates: Effect of some physical,physico-chemical and chemical properties

Aggregate diameter affected significantly the intensity of ammonification in chernozemic rendzina but not in lessivē soil. In the latter the process was influenced significantly by the number of microorganisms able to grow on asparagine agar. A high correlation, though not significant at the level of 0.05, was found between the ammonification intensity and the content of pores of radius: 3–1.5, 7.5–5.0, 0.5–0.25 and 0.01–0.005 μm in chernozemic rendzina and those measuring 1.5–0.5, 0.025–0.01, 0.01–0.005 and >7.5 μm in lessivē soil aggregates as well as the percentage of soil particles of 100–50 μm in chernozemic rendzina aggregates and the internal surface area and organic C in aggregates of lessivē soil.     

The impact of secondary forests conversion into larch plantations on soil chemical and microbiological properties

Background and aims

Conversion of natural forests to plantations often results in a considerable loss of plant species and thus likely a reduction in quantity and quality of plant debris entering the soil. Larch plantation is widespread in northeastern China, but its ecological impacts receive little attention. This study aimed to assess soil quality under larch stands against the secondary forest stands using a suite of soil chemical and microbiological properties.

Methods

Four pairs of larch plantations and secondary forests were randomly selected from a mountainous area and mineral soils of top 15 cm were collected from each field.

Results

Soil carbon (C) and nitrogen (N) concentrations, microbial biomass, C and N mineralization and the activities of hydrolytic enzymes were significantly lower in the larch plantations than those in the secondary forests. However, light fraction C as a proportion of soil C was greater in the larch plantations, suggesting less accumulation and stabilization of soil C to heavy fraction in the larch plantations compared to the secondary forests. We also used δ¹⁵N records in light and heavy fractions to derive the relative stability of soil C and found that soil C stability was lower in the larch plantations. This was supported by Fourier transform infrared spectroscopy analysis because carboxylate stretching, which might result from microbial oxidation, was less abundant in the larch plantations.

Conclusions

The differences in soil organic matter quality between the larch plantations and the secondary forests were reliably reflected in soil microbial properties and microbially-mediated processes. Our results indicated that the larch plantations reduced soil quality as well as nutrient cycling rate.     

不同还田方式对砂质潮土理化性质及微生物的影响

为探索不同物料还田方式对中低产田砂质潮土的改良效果,在黄淮海平原麦玉轮作区典型砂质潮土上进行了连续6季的田间小区试验,设置全量秸秆翻耕还田(TS),秸秆等碳量的生物炭(TB)及半量秸秆半量生物炭配合翻耕还田(TSB),全量秸秆免耕覆盖还田(NTS)和半量秸秆半量生物炭配合免耕覆盖还田(NTSB),共5种还田方式。结果表明,与常规秸秆翻耕还田(TS)相比,生物炭翻耕还田(TB)显著降低土壤容重,增加玉米各个生育期土壤水分和p H值,有机质含量提升了16.4%,但TB处理的土壤大团聚体降低了21.2%和微生物数量降低了16.1%;翻耕秸秆配合生物炭还田(TSB)除了显著降低了大团聚体数量,对其余理化及微生物指标的影响均不显著;免耕模式下的秸秆还田(NTS)和秸秆生物炭配施(NTSB)分别在玉米生长的喇叭口期和收获期显著增加了土壤水分含量、耕层土壤的微生物数量和有效降低砂质潮土分形维数,对容重和有机质含量有一定的改善,其中NTSB有机质含量提升了14.9%和微生物数量增加了53.7%,对砂质潮土改良效果更好。总体来说,短期内用等碳量的生物炭替代秸秆翻耕还田更多的表现为物理的掺混效应,虽能有效提升土壤有机质含量,但不能有效改善砂质潮土的物理结构及生物性质,一半秸秆用生物炭替代还田对该类土壤的理化及微生物指标的改良效果也不显著,而免耕条件下秸秆配合生物碳还田效果最佳,可为砂质潮土的改良提供新的途径和理论依据。     

Effect of organic amendments on some physical, chemical and biological properties in a horticultural soil

The aim of the present work was to assess the response of selected soil physical, chemical and biological properties, after two applications of different organic amendments to a soil with an extended horticultural use. Vermicompost from household solid waste (HSW) and from horse and rabbit manure (HRM), and chicken manure (CM) were applied at rates of 10 and 20 Mg ha(-1). The proportion of water stable soil aggregates (Ws) was significantly higher (p < 0.05) in HSW, HRM and CM at 20 Mg ha(-1). The proportion of ethanol stable soil aggregates (Es) was significantly higher in HSW, HRM and CM at 20 Mg ha(-1), and CM at 10 Mg ha(-1). After the first amendment application, HSW and HRM at 20 Mg ha(-1) resulted in higher soil organic carbon (SOC), while all the treatments showed a significant increase after the second amendment application. Linear relationships were found between Ws and Es with SOC. An increment in microbial respiration in all the amended plots was observed with the exception of HRM at the rate of 10 Mg ha(-1).     

Effect of brewery sludge amendments on some chemical properties of acid soil in pot experiments

A laboratory experiment was performed for an incubation period of 120 days in order to evaluate the changes in chemical properties of an acid soil amended with 0, 15, 30, 60 and 120 t ha-' of brewery sludge (BS). Increasing BS rates and incubation time reduced pH of the soil by 0.3-0.5 unit with respect to the control while soluble salts increased from 0.11 to 0.80 dS m(-1). Organic C, exchangeable cations, soluble cations and anions, NH4+-N and NO3--N contents of the amended soil increased as BS rates increased. In addition, BS application caused a slight increase in cation exchange capacity (CEC) and a slight decrease in exchangeable acidity.     

Influences of vermicomposts on field strawberries: part 2. Effects on soil microbiological and chemical properties

The effects of applications of food waste and paper waste vermicomposts on some soil chemical and biological properties were evaluated in field plots planted with strawberries. Six-week old strawberries (Fragaria ananasa, var. Chandler) were transplanted into 4.5 m(2) raised beds under a plastic tunnel structure measuring 9.14 x 14.6 x 3.6 m. Vermicompost were applied at rates of 5 or 10 t ha(-1) supplemented with inorganic fertilizers to balance fertilizer recommendations for strawberries of 85-155-125 kg NPK ha(-1). Effects of vermicomposts on strawberry growth and yields have been reported previously [Arancon, N.Q., Edwards C.A., Bierman P., Welch, C., Metzger, J.D., 2004. The influence of vermicompost applications to strawberries: Part 1. Effects on growth and yield. Bioresource Technology 93:145-153]. Total extractable N, NH(4)-N, NO(3)-N and orthophosphates did not differ significantly between treatments, except on the last sampling date (harvest date) in which significantly greater amounts of NH(4)-N, NO(3)-N and orthophosphates (P 相似文献   

Grass cover on forest clear-cut areas ameliorates some soil chemical properties

Clear-cut areas formed after forest decline due to acid deposition, pest attacks, or wind-breaks in temperate mountainous regions are often populated by grass (mainly Calamagrostis villosa). This study focused on the changes of soil chemical characteristics under the grass cover replacing the forest, focusing mainly on aluminium (Al) speciation. Clear-cut area due to strong acid deposition in the Jizera Mountains (Northern Bohemia) was studied. The soils under grass cover exhibit higher pH values and lower exchangeable Al content compared to adjacent surviving forest. Mobile Al species under the grass have larger proportion of non-toxic organic complexes. The content of exchangeable base cations is slightly higher under the grass. The positive effect of grass on soil chemistry was enhanced by liming. The temporary grass cover can therefore improve soil chemical quality for following reforestation. However, the differences are generally limited to surface organic horizons. Similar results were found also on a bark-beetle clear-cut area in the Bohemian Forest (Southern Bohemia) with smaller acid deposition; nevertheless, most differences were not significant there.     

沸石对土壤养分生物有效性和土壤化学性质的影响研究

在花岗岩发育的赤红壤上进行的天然沸石混施化肥的盆栽试验研究结果表明,沸石提高了土壤养分的生物有效性,显著促进玉米的生长,增加玉米的生物量和提高了玉米对N,P,K的吸收量,15N示踪技术表明,沸石处理可以显著提高氮肥的利用率,两造玉米最高的氮肥利用率分别比对照提高28．8％和60．0％,土壤的分析结果表明,沸石处理也可提高土壤阳离子交换量,盐基饱和度和土壤pH值。     

凋落物添加条件下咸水灌溉对风沙土CO2排放及化学性质的影响

沙拐枣作为塔克拉玛干沙漠公路防护林主要优势物种之一,其凋落物在该区域的碳循环过程中具有重要作用。采用室内培养试验测定了沙拐枣凋落物添加后,在25%、50%、75%、100%田间持水量的咸水(SW)和淡水(FW)灌溉条件下,风沙土CO₂排放、土壤有机碳(SOC)、可溶性有机碳(DOC)、pH和电导率(EC)的动态变化。结果表明: 咸水灌溉对土壤CO₂排放具有抑制作用,在4种土壤含水量处理下,淡水灌溉比咸水灌溉的CO₂累积排放量增加1.9%～29.1%;土壤CO₂累积排放量随土壤含水量的增加而升高;在沙拐枣凋落物添加条件下,SOC在前期迅速下降,但后期所有处理SOC均逐渐升高后趋于稳定;培养结束时,各处理DOC含量比培养前提高了41.3%～92.4%;在培养结束时各处理与培养前相比pH升高了0.20～0.35;EC随土壤含水量的增加而升高,培养结束时在4种含水量条件下,咸水灌溉下EC比培养前增加了0.11～0.79 mS·cm^-1,而淡水灌溉下EC比培养前有增有减。土壤CO₂累积排放量与SOC、DOC、pH呈显著正相关,但与土壤含水量相关性不显著。凋落物添加条件下咸水灌溉以及较低的含水量条件均能抑制风沙土CO₂的排放,EC受灌溉水质和土壤含水量的影响较大。     

不同树种混交林及其纯林对土壤理化性质影响的研究

对针阔混交林土壤理化性质的研究表明,针阔混交林比针叶树纯林对土壤的改良作用要好,它使土壤总孔隙度增加２—１９％,水分含量增加６—３１％,枯枝落叶年凋落量增加２—２００％;土壤养分含量全Ｎ、ＮＨ４－Ｎ、代换性Ｃａ、代换性Ｍｇ和腐殖质含量分别增加４５—７５％、３３—８２％、５５—８５％、４４—８４％和３７—４６％．     

退化沙质草地开垦和围封过程中的土壤颗粒分形特征

研究了科尔沁退化沙质草地开垦和围封过程中土壤颗粒分形维数的变化特征,以及分形维数与土壤性状的关系.结果表明,不同开垦和围封年限的土壤颗粒分形维数(0～30cm)介于2.387～2.588之间.随着开垦年限的增加,0～15 cm层土壤颗粒分形维数从2.441降至2.387;围封11年后,0～15 cm层土壤颗粒分形维数增加到2.588.15～30 cm层土壤颗粒分形维数无明显变化.土壤颗粒分形维数是反映土壤质地的一个较好指标,重点反映粘粒含量,其次是粉粒含量.分形维数的变化能够很好地表征退化沙质草地土壤的化学、物理和生物学性状的变化趋势,可以作为评价退化沙质草地土壤性状的一个综合指标.     

Qualitative microbiological changes during decomposition of plant material in a sandy sierozem soil

The successive qualitative microbial changes during the decomposition of bajra stalk in a sandy sierozem soil were studied.Alternaria spp.,Aspergillus spp.,Cladosporium spp.,Fusarium spp.Gliocladium spp.,Mucor spp. andRhizopus spp. were most common fungi. The bacteria observed wereAchromobacter, Arthrobacter, Bacillus, Micrococcus, Pseudomonas andXanthomonas. Cellvibrio andCellulomonas were also observed.     

深挖垦复对锥栗重要农艺性状及土壤理化性质的影响

为探索锥栗林地高效的土壤管理方式,提升我国锥栗栽培管理技术水平,进而提高其产量、品质以及经济效益。该研究采用全垦和环垦两种方式对锥栗林地进行连续4年的深挖垦复,通过测定垦复前后土壤理化性质变化以及锥栗树体生长、叶片表型和生理特征、结果性状、产量及品质等重要农艺性状,统计数据并进行对比分析。结果表明:(1)深挖垦复对锥栗林地土壤理化性质改善效果显著,两种垦复方式土壤容重较垦复前降低31.21%及以上(0～30 cm处),土壤含水率、土壤孔隙度、有机质含量以及各种大量元素含量较垦复前和对照均有不同程度的增加,土壤肥力及其保水保肥能力显著增强。(2)环垦区土壤有机质含量、有效磷含量以及交换性镁含量高于全垦区,其土壤有机质含量较垦复前增加40.59%,远高于全垦增加幅度(17.76%),从土壤保肥能力的角度来看,环垦效果优于全垦。(3)土壤肥力的提升增强了其对锥栗叶片的供肥能力,使得叶片含水率、叶绿素含量以及各种矿质元素含量显著增加,从而提升其光合作用能力。(4)深挖垦复对锥栗树体生长、结实能力、产量及品质同样具有显著的提升效果,其中全垦和环垦区单位面积产量分别是对照的1.75倍和1.33倍,且栗苞总重、单果质量、出籽率、可溶性糖含量以及磷、钾元素含量显著高于对照,而空苞率显著低于对照。综上,深挖垦复是改良林地土壤和提高锥栗生产力的有效举措。     

Recycling of organic matter through mulch in relation to chemical and microbiological properties of soil and crop yields

Summary Field experiments were conducted to investigate the effect of organic mulching on the nutrient status, microbiological properties and the yield of maize and green gram crops. Soil organic carbon and humin and humus carbon of the fallow and the cropped soils were augmented by mulching. More of nitrogen, available phosphorus and ammoniacal and nitrate nitrogen were found in mulched soils. Soil reaction was not affected by mulching. Mulched treatments maintained more of soil moisture and soil temperature lowered during summer and rainy seasons. Population of bacteria, fungi, actinomycetes and Azotobacter were augmented in mulched treatments at all the stages of sampling. Mulching significantly increased the grain and straw yield of both the crops. The nitrogen uptake by grain was higher in mulched than in the unmulched treatments.     

海南岛不同地形上某些土壤化学性质的多样性分析

多样性指数长时间以来在生态学领域被用于分析不同生态体的发生规律．将类似手段用于某些土壤化学性质(土壤pH值、表层阳离子代换量和表层有机质含量)多样性的分析中,讨论了基于海南岛土壤一地体数字化数据库(SOTER),通过对不同地形上土壤pH值、表层阳离子代换量和表层有机质含量类别SOTER单元的丰富度指数(S)、多样性指数(Shannon指数H’)和均匀度指数(Pielou E)的计算,建立了类别多度分布模型,并在地理信息系统环境中实现了海南岛不同地形上土壤化学性质多样性分析的数字化表达．研究表明,上述研究路线具有可操作性。几种多样性指数和多度分布模型的建立可以较好地反映不同地形上土壤化学性质类别的空间变异特点．因此,SOTER单元作为土壤性质多样性的测度单元是可行的．