松嫩平原北部寒变性土的研究

2008年在黑龙江省松嫩平原北部的北安市(47.53°N,126.16°E)和依安县(47.45°N,125.13°E)所在的乌裕尔河阶地上的寒均腐土地区,进一步观察了7个土壤剖面,发现其中有3个剖面具有变性特征。其母质有第四系中更新世(Qp2)黄土性冲-湖积物,和白垩系的泥页岩风化物(K2)。诊断特征:全剖面黏粒(<2μm)含量330～480 g.kg-1;心土层棱柱状结构破碎成棱块状;可见楔形结构,或滑擦面;旱季土壤开裂,冻融期和雨季闭合。线膨胀系数可高达0.19 cm.cm-1,土壤代换量在34～37 cmol.kg-1之间。黏土矿物以伊蒙混层、蒙皂石为主,控制层段的蒙皂石总量约占66%～70%。按美国土壤系统分类检索,符合变性土纲的鉴定标准,将其划归寒变性土亚纲(Cryerts),其中土类有简育寒变性土(Haplocryerts),亚类有典型简育寒变性土(Typic Haplocryerts)和艳色简育寒变性土(Chromic Haplocryerts)。研究认为,本地的寒变性土主要是由于原母质和某些寒均腐土的心土层累积了大量膨胀性的伊蒙混层和蒙皂石黏土矿物,在干湿交替的气候和加速土壤侵蚀等综合因素影...     

Effects of illite supplementation on in vitro and in vivo rumen fermentation,microbial population and methane emission of Hanwoo steers fed high concentrate diets

This study was conducted to evaluate the effects of feeding supplemental illite to Hanwoo steers on methane (CH₄) emission and rumen fermentation parameters. An in vitro ruminal fermentation technique was conducted using a commercial concentrate as substrate and illite was added at different concentrations as treatments: 0%, 0.5%, 1.0%, and 2.0% illite. Total volatile fatty acids (VFA) were different (P < 0.05) at 24 h of incubation where the highest total VFA was observed at 1.0% of illite. Conversely, lowest CH₄ production (P < 0.01) was found at 1.0% of illite. In the in vivo experiment, two diets were provided, without illite and with addition of 1% illite. An automated head chamber (GreenFeed) system was used to measure enteric CH₄ production. Cattle received illite supplemented feed increased (P < 0.05) total VFA concentrations in the rumen compared with those fed control. Feeding illite numerically decreased CH₄ production (g/day) and yield (g/kg dry matter intake). Rumen microbial population analysis indicated that the population of total bacteria, protozoa and methanogens were lower (P < 0.05) for illite compared with the control. Accordingly, overall results suggested that feeding a diet supplemented with 1% illite can have positive effects on feed fermentation in the rumen and enteric CH₄ mitigation in beef cattle.     

水溶性有机碳在各种粘土底土中的吸附：土壤性质的影响

Clay-rich subsoils are added to sandy soils to improve crop yield and increase organic carbon (C) sequestration; however, little is known about the influence of clay subsoil properties on organic C sorption and desorption. Batch sorption experiments were conducted with nine clay subsoils with a range of properties. The clay subsoils were shaken for 16 h at 4 ^oC with water-extractable organic C (WEOC, 1 224 g C L^-1) from mature wheat residue at a soil to extract ratio of 1:10. After removal of the supernatant, the residual pellet was shaken with deionised water to determine organic C desorption. The WEOC sorption was positively correlated with smectite and illite contents, cation exchange capacity (CEC) and total organic C, but negatively correlated with kaolinite content. Desorption of WEOC expressed as a percentage of WEOC sorbed was negatively correlated with smectite and illite contents, CEC, total and exchangeable calcium (Ca) concentrations and clay content, but positively correlated with kaolinite content. The relative importance of these properties varied among soil types. The soils with a high WEOC sorption capacity had medium CEC and their dominant clay minerals were smectite and illite. In contrast, kaolinite was the dominant clay mineral in the soils with a low WEOC sorption capacity and low-to-medium CEC. However, most soils had properties which could increase WEOC sorption as well as those that could decrease WEOC sorption. The relative importance of properties increasing or decreasing WEOC sorption varied with soils. The soils with high desorption had a low total Ca concentration, low-to-medium CEC and low clay content, whereas the soils with low desorption were characterised by medium-to-high CEC and smectite and illite were the dominant clay minerals. We conclude that WEOC sorption and desorption depend not on a single property but rather a combination of several properties of the subsoils in this study.     

Radiocesium interception potential (RIP) of smectite and kaolin reference minerals containing illite (micaceous mineral) as impurity

Cesium-137 (¹³⁷Cs) is strongly adsorbed on clay minerals, especially on illite. The adsorption of Cs⁺ on reference clay minerals, however, has not been fully investigated in relation to the presence of illite. The objective of this study was to clarify the effect of impurities (i.e., illite and vermiculite), present in reference smectite group minerals and kaolin minerals, on the retention of Cs⁺. The clay mineralogy of the reference minerals was characterized by X-ray diffraction (XRD). The radiocesium interception potential (RIP) was measured as an index of the Cs⁺ retention ability of clays. The content of illite in clay was represented by the total potassium (K) content given that illite is a major source of K in the clay fraction. The content of vermiculite in clay was represented by the Cs fixation capacity induced by Cs saturation followed by heating of samples at 110°C. Metabentonite and beidellite gave extremely high RIP values compared with other smectite group minerals, although a peak for illite (at 1.0 nm) was not observed in XRD analysis. The reference smectite and kaolin minerals showed a range of RIP values, even though their RIP values are theoretically zero. The RIP values had a significant positive correlation with the total K content of all the reference clay minerals (r_s = 0.621*). This indicated that the retention ability for ¹³⁷Cs depended more on the content of illite, as impurity, rather than the type of bulk mineral. Hence, the contribution of illite to the magnitude of the RIP was elucidated by the combination of measurement of total K content and XRD analysis.     

Short‐time clay‐mineral evolution in a soil chronosequence in Oléron Island (France)

Major weathering sequences in soils are well established; however, knowledge on rates of mineral transformations remains unknown, because it is often difficult to date precisely soil processes. This work was carried out on soils developed on recent (< 188 y) sand dunes on the W coast of Oléron Island (France). The coast has been protected against marine and wind erosion by constructing five consecutives barriers close to the coastline since 1820 (1820, 1864, 1876, 1889, 1948) defining the maximum age of the soil parent material, as before the areas between the barriers were under water. Soils on the older dunes have low clay content (> 94% of sand) and exhibit a bleached E horizon that overlies a yellowish brown B horizon. The process responsible for their formation is podzolization promoted by the high permeability of the material and complexing organic matter produced by coniferous vegetation. Initial mineralogy of C horizons is homogenous and constituted of chlorite, illite, illite/smectite mixed‐layer minerals, and kaolinite, quartz, calcite (≈ 8% related to shell fragments), and feldspars. The initial clay‐mineral assemblage of the E horizons is dominated by illite (well‐crystallized WCI and poorly crystallized PCI) and chlorite. With progressive podzolization, poorly crystallized illite is first transformed to illite/smectite mixed‐layer minerals and in a further step into smectite. In addition, transformation of well‐crystallized illite leads to formation of ordered illite/smectite mixed‐layer minerals in the E horizons, which is not commonly described in soils. In the B horizons, illite/smectite mixed‐layer minerals are present with traces of smectite, as well as Al and Fe oxi‐hydroxides as revealed by DCB and oxalate chemical extractions. This chronosequence illustrates that over short distances and short time (< 188 y) intense mineral weathering and soil development occur. Major clay‐mineral changes occur between 132 and 188 y in agreement with development of the pine forest producing acidic litter.     

红层软岩崩解性的灰色关联分析

采用灰色关联度法对红层软岩的粒度分形特征以及矿物、化学成分试验数据与其崩解性进行了关联分析.分析发现,与成分相比,红层软岩的粒度分布分形特征参数与崩解特性具有更高的关联度,表明沉积形成时的环境决定了成岩后的红层软岩崩解性强弱.因为红层软岩中蒙脱石含量少,因此在各种成分中伊利石含量对红层软岩崩解性影响最大,说明水理特性不稳定的矿物含量始终是影响软岩崩解的主要因素.     

类芽胞杆菌W51菌剂制备及对番茄青枯病的防效研究

青枯病是由青枯劳尔氏菌Ralstonia solanacearum引起的一种土传病害。本研究将制备得到的伊利石吸附W51菌剂作用于防治番茄青枯病的温室试验。结果表明,伊利石吸附W51菌剂中的伊利石最佳剂量为4%,最佳吸附时间为30 min,在该条件下伊利石对菌体的吸附率达到90.78%;温室试验中,伊利石吸附W51菌剂处理组在第14 d仍然表现出较好的防效62.29%,远高于类芽胞杆菌Paenibacillus sp.W51菌悬液处理组的42.91%。本研究表明,伊利石吸附W51菌剂相对于单一的类芽胞杆菌Paenibacillus sp.W51对番茄青枯病有较高的防治效果。     

伊利石对仔猪生长性能、抗氧化和免疫功能及肠道形态的影响

本试验旨在研究饲粮中添加伊利石对断奶仔猪生长性能、养分消化率、血清抗氧化和免疫功能、肠道形态及粪便氮素排放的影响。选取144头28日龄健康"杜×长×大"断奶仔猪[平均体重(7.27±0.89)kg],按完全随机区组设计分为3组,每组8个重复,每个重复6头猪(公母各占1/2)。对照组饲喂玉米-豆粕型基础饲粮,试验组分别在基础饲粮中添加2 000和4 000 mg/kg伊利石(替代等量的玉米)。试验期28 d。结果表明,与对照组相比:1)试验第1~14天和第1~28天,4 000 mg/kg伊利石添加组仔猪平均日增重和增重耗料比显著提高(P<0.05);试验第1~14天,4 000 mg/kg伊利石添加组仔猪腹泻率显著降低(P<0.05)。2)4 000 mg/kg伊利石组仔猪干物质、粗蛋白质和总能表观消化率在试验第1~14天显著提高(P<0.05),粗蛋白质表观消化率在试验第15~28天显著提高(P<0.05)。3)试验第14天,4 000 mg/kg伊利石添加组仔猪血清免疫球蛋白A和免疫球蛋白G含量、超氧化物歧化酶活性和总抗氧化能力(T-AOC)显著提高(P<0.05),血清丙二醛含量则显著降低(P<0.05);试验第28天,4 000 mg/kg伊利石添加组仔猪血清T-AOC显著提高(P<0.05)。4)4 000 mg/kg伊利石添加组仔猪空肠和回肠绒毛高度/隐窝深度(V/C)值显著升高(P<0.05),试验组回肠绒毛高度(P=0.07)和十二指肠V/C值(P=0.06)有升高的趋势。5)4 000 mg/kg伊利石添加组仔猪每千克体增重粪氮排放量在试验第1~14天显著降低(P<0.05),试验组仔猪在试验第15~28天每千克体增重粪氮排放量有降低的趋势(P=0.06)。综上,饲粮添加4 000 mg/kg伊利石可显著提高断奶仔猪机体抗氧化和免疫功能,改善肠道形态,降低腹泻率,提高养分消化率,减少粪便氮素排放,促进仔猪生长。     

辽宁棕黄土母质的特征及其成因初探

辽东和辽北的黄土状沉积物称为棕黄土,以区别于典型黄土,分布于高出现代河床20～30米的岗台地上。根据产状、颗粒组成和矿物成分。它们可能是风成的。昌图县的棕黄土可能来自内蒙沙地,大连附近的黄土可能来自北面的海域,其中含有有孔虫,宽甸盆地中的棕黄土则以大气尘降落的形式形成的。各地棕黄土中的矿物组成也不同,缓效钾的含量与粘粒含量成正相关,表明伊利石是其中的主要组成成分。