桂林毛村不同地质背景主要元素迁移特征及与植物蒸腾作用的相关性

对桂林毛村不同地质背景(石灰岩、白云岩和砂页岩)土壤中Ca、Mg、Cu、Fe、Mn、Zn等主要元素的迁移特征进行了研究,结果表明母岩的地球化学背景对岩溶土壤系统的元素迁移具有重要影响.同时,以不同地质背景生长的典型植物黄荆为例,研究了上述元素的迁聚与植物蒸腾作用的相关性.结果表明,植物蒸腾作用对土壤中Ca、Mg、Cu、Fe、Mn、Zn等主要元素迁聚的影响程度因不同地质背景以及不同元素而有明显差异.植物蒸腾作用对Mn、Cu等较难迁移元素的迁移具有一定促进作用.土壤中Cu、Fe、Mn、Zn等微量元素的迁聚对植物吸收系数的影响程度因不同地质背景而有显著差异.岩溶山区进行植被恢复时必须考虑不同地质背景的差异,因地制宜地选择合适的植物品种.     

非金属矿物改良皖南酸性红黄壤应用研究

应用非金属矿物沸石(尿素沸石)、白云石改良皖南地区酸性红黄壤,结果表明:盆栽玉米、大豆植株干物重增加39.4%-54.5%,NPK吸收量增加25.7%-52.7%;大田试验玉米产量增加23.5%,NPK吸收量增加8.2%-30.6%。沸石(尿素沸石)与白云石配合效果好,是改良酸性红黄壤有效途经。     

白云石粉对皖南酸性红黄壤磷组分及磷有效性的影响

在施用P肥的基础上配合使用白云石粉,用酸性土壤无机P分级方法测定皖南红黄壤各形态P的含量。结果表明:使用P肥能明显提高土壤全P、无机P和土壤速效P含量;土壤速效P与无机P各组分的相关性以Al-P最好,Fe-P、O-P次之,Ca-P最差。施用白云石粉,当季土壤Ca-P含量及其在无机P中所占的比例明显提高,Al-P的形成受到抑制,但随着时间的推移,却更有利于有效性较高的Al-P含量的增加。     

白云石对酸性红黄壤上油菜、玉米的效应

施用白云石改良酸性红黄壤田间定位试验第3、4季油菜和玉米的试验结果表明:施用白云石的处理与对照比较仍能明显地促进油菜、玉米的生长发育,改善作物经济性状,显著地提高作物的籽粒产量.其中施用1 600 kg/hm2白云石处理的油菜、玉米的产量最高,分别为2 518、4 928 kg/hm2,比对照分别增产16.2 %和 44.6%;经济效益最好,经济效益分别为4 734和4 435元/hm2.施用白云石表现出了显著的后效.     

Soil quality indicators in Vertisols under sugarcane

Maintaining or improving soil quality is crucial for agricultural productivity. This study was undertaken on the north coast of Cuba with the objective to select soil quality indicators to characterise Vertisols. For the selection of soil quality indicators, we have conducted four field experiments where organic fertilisers (sugarcane filter cake, compost) and natural minerals (dolomite, zeolite) were applied. Sugarcane (Saccharum officinarum L.) was used in all experiments. Soil properties were determined such as the amount of water-stable aggregates, permeability, plastic limit, pH in water, pH in KCl, organic matter, P₂O₅ and K₂O. The sugarcane yield components such as cane yield (t ha^?1) and sucrose yield (t ha^?1) were evaluated. Principal components analysis and simple regression analysis were also performed. Both organic matter and water-stable aggregates were closely related to cane yield, with r values of 0.87–0.97. The properties with best responses to treatments over time were permeability, water-stable aggregates, degree of soil aggregation and organic matter; therefore, they can be considered as soil quality indicators for the studied Vertisols.     

Sedimentary and diagenetic features in saline lake deposits of the Monegros region, northern Spain

The Monegros region in northern Spain is marked by the occurrence of a large number of ephemeral to dry lake basins, occupying small karstic depressions. The lacustrine sediment fill of these basins contain various carbonate and silicate minerals whose origin and palaeoenvironmental significance is poorly understood. For the present study, 14 lake basins were sampled in order to establish vertical, lateral and regional variations in mineralogical and textural characteristics, aimed at determining the mode of formation of the various mineral phases present. In nearly all basins, the same sequence of three lithological units is recognized, including a basal clayey unit, a middle magnesite-bearing and gypsum-rich unit, and a calcite- and dolomite-dominated surface unit. Distribution patterns of carbonate minerals indicate that magnesite is a synsedimentary precipitate, dolomite formed as a diagenetic authigenic phase, and calcite is partly authigenic and partly allogenic. All clay minerals, including sepiolite and smectite, appear to be allogenic. Regional variations are marked by similarities between groups of neighbouring basins, but no overall trend related to regional drainage patterns is recognized. The middle lithological unit records a lake stage with predominantly chemical sedimentation (Unit II), overlying a less well documented interval corresponding to a perennial lake stage with lower salinity (Unit III), whereas the surface unit formed during a period with predominantly clastic sedimentation. Based on a comparison with other regional records, the middle unit is attributed to an Early Holocene humid stage, separated from the overlying Late Holocene deposits by a hiatus that corresponds to a Mid Holocene arid stage.     

Regeneration niches of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> [L.] Karst.) saplings in small canopy gaps in mixed mountain forests of the Bavarian Limestone Alps

Natural regeneration measurements are the main silvicultural objective in overaged protective forests of the Bavarian Limestone Alps. While manifold problems with these stands, especially the impact of browsing, are widely recognised, the regeneration niches of Norway spruce (Picea abies [L.] Karst.) are insufficiently known. The purpose of this study was to determine favourable combinations of site factors for the development of spruce in small, unfenced canopy gaps, located on Aposerido-Fagetum caricetosum albae forest sites. We recorded the occurrence of spruce saplings (as dependent variable) and of six site factors (as independent variables) on 480 0.5 m²-subplots. In addition, we estimated the coverage of six acid adapted plant species to determine correlations with the humus depth. A binary logistic regression analysis was used to predict the probability of the occurrence of a spruce sapling in dependency of the different site factors. Supported by other studies, we assumed that the supply of solar radiation was adequate for the sufficient regeneration of spruce within the canopy gaps. Other site factors significantly determined the regeneration niches of spruce saplings. More spruce saplings were found near hindrances and on rough surfaces than would be expected from a random occurrence of saplings. These microsite types may have characteristics, especially protection against snow gliding that promotes spruce establishment. A calculated “hindrance index”, which accounted for the number, and the distance of surrounding hindrances might be a good specific value to describe the influence of hindrances on steep slopes. The sapling establishment decreased on thin humus layers. Our assumption for the sites was that thick organic layers might represent a good seedbed for spruce. Decayed dead wood was scarce, but was exceedingly favoured by spruce saplings. Results obtained suggest that the natural regeneration establishment of spruce on steep slopes can be successfully influenced by site factors which inhibit the influence of snow gliding. According to a “positive microsite” concept, we recommend for artificial regeneration measurements with spruce, microsites close to hindrances (e.g. stumps, downed trees) and Vaccinium myrtillus as a predictor for thick, acid humus layers.     

Kinetics of bacterial death by heated dolomite powder slurry

The kinetics of the bactericidal action of dolomite powders heated at 600-1000 °C against Escherichia coli and Staphylococcus aureus were investigated. Dolomite powder heated to at least 700 °C exhibited bactericidal action, and the process of bacterial death in the heated dolomite powder slurries followed first-order reaction kinetics. The value of the death rate constant (k) increased with dolomite powder concentration, and the dilution coefficient (n), which indicates the dependence of k on the reagent concentration, was measured. The n values of the powder heated at 700 °C and at temperatures >900 °C were almost identical to those of MgO and CaO, respectively. This suggests that the first emergence of bactericidal action at 700 °C corresponds to generation of MgO while that at temperatures >900 °C is due to generation of CaO. The slurry temperature significantly affects the bactericidal action. The slope of the Arrhenius plot of k for E. coli and S. aureus grown at 37 °C exhibited a discontinuous point at approximately 22 °C, where a change in the value of activation energy for bacterial death occurred. This temperature corresponds to that of the phase transition of cell membrane lipids.     

Effects of Lime and Wood Ash on Soil-solution Chemistry,Soil Chemistry and Nutritional Status of a Pine Stand in Northern Germany

Lime and wood ash may be useful to improve acidic forest soils. A field experiment was conducted in a pine stand on a sandy podzol at Fuhrberg, Germany, which involved an application of dolomitic lime (3 t ha^-1) with three replications or wood ash (4.8 t ha^-1) without replications on the forest floor. During the 2 yr study period, lime affected the soil solution composition only slightly. Ash had a marked effect on solution chemistry of the mineral soil at 10 cm and the pH values dropped temporarily from 3.7 to 3.1. Nineteen months after the treatments, exchangeable calcium in the organic layer and mineral soil increased by 222 (lime addition) or 411 kg ha^-1 (ash addition) and exchangeable magnesium increased by 101 (lime addition) or 39 kg ha^-1 (ash addition). After ash addition, no marked change in heavy metal content was found below 4 cm of the organic layer. In the ash treatment, the potassium concentration of the 1-yr-old pine needles increased from 5.6 to 5.9 g kg^-1. This study suggests that ash from untreated wood may be recommended for amelioration of forest soils.     

硫和白云石对皖中黄褐土铅形态分布的影响

通过室内土壤培养试验,应用连续浸提分组方法,研究了S与白云石用量对黄褐土中重金属Pb形态分布的影响.结果表明,高S处理条件下,土壤pH下降,可交换态Pb有升高的趋势:白云石处理条件下,土壤pH升高,显著促进了可交换态Pb向碳酸盐结合态和铁锰氧化态转化,这种形态分布与白云石用量无明显关联,S的添加不足以改变白云石粉对黄褐土中Pb形态的影响.