长期定位施肥对土壤腐殖质理化性质的影响

 以潮土、旱地红壤和红壤性水稻土为研究对象 ,探讨了长期施肥对土壤腐殖质含量与性质的影响。结果表明 ,长期施肥不仅影响土壤腐殖质的含量与组成 ,还影响腐殖质的理化性质。施有机肥或有机无机肥配施降低潮土和旱地红壤胡敏酸的E4和E6值 ,提高红壤性水稻土胡敏酸的E4和E6值。单施化肥也能提高红壤性水稻土胡敏酸的E4和E6值 ,但对潮土和旱地红壤胡敏酸E4和E6值影响不大。长期施肥对土壤耕层富里酸可见光谱的影响与胡敏酸不同 ,施有机肥或有机无机肥配施均能提高 3种土壤富里酸的E4和E6值 ,单施化肥对 3种土壤富里酸的E4和E6值基本上没有影响。长期施肥也影响腐殖质的紫外吸收光谱 ,长期施用有机肥或有机无机肥配施均能提高 3种土壤胡敏酸和富里酸的紫外吸收光谱值 ,但这种作用只在短波长方向明显 ,随着波长的增加影响减小。单施化肥也可以提高富里酸的紫外吸收值 ,但只能提高潮土胡敏酸的紫外吸收值。长期施用有机肥或有机无机肥配施均能提高 3种土壤胡敏酸和富里酸的总酸性基、羧基和酚羟基含量 ,单施化肥对胡敏酸和富里酸含氧功能团含量的影响不大     

苏皖南部丘陵茶园土壤的腐殖质组成及性质的研究

本文是对安徽祁门和十字铺、江苏宜兴和深水等地不同肥力水平的茶园土壤腐殖质含量、组成与性质的研究。土壤类型包括黄壤,红壤和黄棕壤。三个地区茶园土壤腐殖质组成都以富里酸为主,不同地区HA/FA值自黄壤向黄棕壤递增,同一地区高产茶园土壤HA/FA值大于低产茶园土壤,胡敏酸光密度值以黄壤最高,红壤居中,黄棕壤最低。     

紫色土发育成的水稻土微团粒结构中有机－无机复合体的性质

This paper deals with characteristics of organo-mineral complexing of microaggregates in the paddy soils developed from purple soils in Sichuan, China. Results show that the contents of organic matter in microaggregates are in the order of 1-0.25 mm > smaller than 0.05 mm > 0.05-0.25 mm. But the organic matter in 1-0.01 mm microaggregates accounts for 68.1%-78.7% of that in soil. The organic matter in < 0.05 mm microaggregates is complexed humus on the whole, of which the degree of organo-mineral complexing varies between 96.1% and 99.5%, which is higher than that of the soil or > 0.05 mm microaggregates. The contents of loosely combined humus and the ratios of loosely and tightly combined humus markedly decline with the size of microaggregates. Flesh soil humus formed from semi-decomposed organic material or organic manure added is combined first with < 0.001 mm clay, and then aggregated with other organic and mineral particles to form larger microaggregates, in which the aging of humus happens at the same time; whereas organic matter of the light fraction is mainly involved in the formation of > 0.05 mm microaggregates.     

Spatial variability of O layer thickness and humus forms under different pine beech–forest transformation stages in NE Germany

Spatial variability of humus layer (O layer) thicknesses can have important impacts upon soil water dynamics, nutrient storage and availability, as well as plant growth. The purpose of the present study was to elucidate the impact of forest‐transformation practices on the spatial variability of O layer thicknesses. The study focused on the Kahlenberg forest area (NE Germany) with stands of Scots pine (Pinus sylvestris) and European beech (Fagus sylvatica) of different age structures that form a transformation chronosequence from pure Scots pine stands towards pure European beech stands. Topsoil profiles including both, the O layer and the uppermost humic mineral soil horizon were excavated at intervals of 0.4 m along 15–20 m long transects, and spatial variability of O layer thicknesses was quantified by variogram analysis. The correlation lengths of total O layer thickness increased in the sequence consisting of pure pine stand (3.1 m) → older mixed stand (3.7 m) → pure beech stand (4.5 m), with the exception of the younger mixed stand, for which no correlation lengths of total O layer thickness could be determined. The degree of spatial correlation, i.e., the percentage of the total variance which can be described by variograms, was highest for the two monospecies stands, whereas this percentage was distinctly lower for the two mixed stands. A similar minimum for the two mixed stands was observed for the correlation lengths of the Oh horizon. These results suggest that the spatial structures of forest‐transformation stands may be interpreted in terms of a disturbance (in the form of the underplanting of beech trees). After this disturbance, the forest ecosystem requires at least 100 y to again reach relative equilibrium. These findings are in line with the results of other soil‐related investigations at these sites.     

Wood-ash fertilization and fire treatments in a Scots pine forest stand: Effects on the organic layer,microbial biomass,and microbial activity

We studied the reactions of humus layer (F/H) microbial respiratory activity, microbial biomass C, and the fungal biomass, measured as the soil ergosterol content, to the application of three levels of wood ash (1000, 2500, and 5000 kg ha^-1) and to fire treatment in a Scots pine (Pinus sylvestris L.) stand. Physicochemical measurements (pH, organic matter content, extractable and total C content, NH ₄ ⁺ and total N content, cation-exchange capacity, base saturation) showed similarity between the fire-treated plots and those treated with the lowest dose of wood ash (1000 kg ha^-1). The ash application did not change the level of microbial biomass C or fungal ergosterol when compared to the control, being around 7500 and 350 g g^-1 organic matter for the biomass C and ergosterol, respectively. The fire treatment lowered the values of both biomass measurements to about half that of the control values. The fire treatment caused a sevenfold fall in the respiration rate of fieldmoist soil to 1.8 l h^-1 g^-1 organic matter compared to the values of the control or ash treatments. However, in the same soils adjusted to a water-holding capacity of 60%, the differences between the fire treatment and the control were diminished, and the ash-fertilized plots were characterized by a higher respiration rate compared to the control plots. The glucose-induced respiration reacted in the same way as the water-adjusted soil respiration. The metabolic quotient, qCO₂, gradually increased from the control level with increasing applications of ash, reaching a maximum in the fire treatment. Nitrification was not observed in the treatment plots.     

An Andosol from Eastern Saxony,Germany

We tested whether a ‘Lockerbraunerde’ from the heights of the Zittauer Gebirge in Eastern Saxony exhibited andic properties and classified it according to the rules of the World Reference Base for Soil Resources (WRB, 1998). To achieve this, we characterized a selected soil by means of routine soil analysis; selective dissolution procedures; X‐ray diffraction (XRD); X‐ray fluorescence (XRF), and Transmission Electron Microscopy (TEM). We used field criteria (Thixotropy; NaF‐field test) to obtain a map of the spatial distribution of soils with potential andic properties. We found that the soil fulfilled all requirements to be classified as an Andosol. The composition of the colloidal phases was exactly intermediate between sil‐andic and alu‐andic. At the same time, the soil had a spodic horizon [determined through the depth function of the Al_o+½Fe_o criterion]. As there was no indication of vertical translocation of metal‐organic complexes, but sufficient evidence to suggest the downward movement of mobile Al/Si‐phases, we maintain to classify the soil as an Endoskeleti‐Umbric Andosol and propose the existence of a pedogenetic pathway intermediate between Podsolisation and Andosolization. We conclude that the spodic horizon in the WRB is not well defined because of the dominance of the Al_o+½Fe_o criterion over morphological evidence. We further suggest the German soil taxonomy to be modified to better represent soils containing short range order minerals.     

Prolonged simulated acid rain treatment in the subarctic: Effect on the soil respiration rate and microbial biomass

Humus chemistry and respiration rate, ATP, ergosterol, and muramic acid concentration as measures of chemical properties, microbial activity, biomass, and indicators of fungal and bacterial biomass were studied in a long-term acid rain experiment in the far north of Finnish Lapland. The treatments used in this study were dry control, irrigated control (spring water, pH 6), and two levels of simulated acid rain (pH 4 and pH 3). Originally (1985–1988), simulated acid rain was prepared by adding both H₂SO₄ and HNO₃ (1.9:1 by weight). In 1989 the treatments were modified as follows. In subarea 1 the treatments continued unchanged (H₂SO₄+HNO₃ in rain to pH 4 and pH 3), but in subarea 2 only H₂SO₄ was applied. The plots were sampled in 1992. The acid application affected humus chemistry by lowering the pH, cation exchange capacity, and base saturation (due to a decrease in Ca and Mg) in the treatment with H₂SO₄+HNO₃ to pH 4 (total proton load over 8 years 2.92 kmol ha^-1), whereas the microbial variables were not affected at this proton load, and only the respiration rate decreased by 20% in the strongest simulated acid rain treatment (total proton load 14.9 kmol ha^-1). The different ratios of H₂SO₄+HNO₃ in subareas 1 and 2 did not affect the results.     

Wood ash fertilization alters the forest humus Archaea community

The combined and separate effects of Cd and wood ash on Archaea from coniferous forest humus were studied in a microcosm experiment. Nonmetric multidimensional scaling of the denaturing gradient gel analysis of polymerase chain reaction amplified 0.9 kb 16S ribosomal DNA fragments revealed changes in archaeal communities due to the ash treatments. Cd with or without ash did not further influence the result. Representatives of the ash and control communities were cloned, grouped by restriction fragment length polymorphism analysis and finally sequenced. All sequences belonged to non-thermophilic Crenarchaea.     

基质配比对野生花卉状元红扦插繁殖的影响

为研究不同插穗基质对状元红[Clerodendrum japonicum(Thunb.)Sweet]扦插生长的影响,采用黄泥和腐殖质混合配比对野生花卉状元红进行扦插试验。结果表明,7种不同基质的扦插苗生根率、生根个数、根长、新梢长之间存在明显差异。高比例腐殖质混合基质扦插苗生根效果最佳,黄泥∶腐殖质=1∶3(V∶V)的混合基质最适合状元红插穗的生长,因此建议在生产上推广应用。     

张家界植烟土壤的有机无机复合状况及其与土壤养分的关系

用傅积平改进法测定了张家界植烟土壤的有机无机复合状况,并分析了其与土壤养分的关系.结果表明:腐殖质的结合形态主要以松结态和紧结态为主,稳结态腐殖质含量最少;土壤复合量与松结态腐殖质、紧结态腐殖质和有机质均呈极显著正相关,有机无机复合度仅与有机质呈显著负相关.3种结合态腐殖质中,松结态与土壤养分(全氮、全磷和有机质)的相关性最高,土壤全钾与腐殖质没有明显的相关性.松结态腐殖质主要是铁、铝键结合的腐殖质,稳结态腐殖质则主要是钙键结合的腐殖质.腐殖质不同形态与土壤pH值、阳离子交换量(CEC)、交换性钙、交换性镁、有效硫和有效铁之间都有着密不可分的联系.