Response of Nematodes in a Hapli-Udic Argosol to Urea Amended with Urease and Nitrification Inhibitors

Effects of urea amended with urease and nitrification inhibitors on soil nematode communities were studied in a Hapli- Udic Argosol （Cambisol, FAO） in Liaoning Province of Northeast China. A completely random design with four treatments, i.e., conventional urea （CU）, slow-release urea amended with a liquid urease inhibitor （SRU1）, SRU1 ＋nitrification inhibitor dicyandiamide （SRU2）, and SRU1 ＋ nitrification inhibitor 3,5-dimethylpyrazole （SRU3） and four replicates were applied. Thirty-nine genera of nematodes were identified, with Cephalobus and Aphelenchus being dominant; and in all treatments, the dominant trophic group was bacterivores. In addition, during the growth period of spring wheat （Triticum aestivum L.）, soil urease activity was lower in SRUs than in CU. The numbers of total nematodes and bacterivores at wheat heading and ripening stages, and omnivores-predators at ripening stage were higher in SUR3 than in CU, SRU1 and SRU2 （P 〈 0.05）.

Binding and Adsorption Energies of Heavy Metal Ions with Hapli-Udic Argosol and Ferri-Udic Argosol Particles

Gibbs free binding energy and adsorption energy between cations and charged soil particles were used to evaluate the interactions between ions and soil particles. The distribution of Gibbs free adsorption energies could not be determined experimentally before the development of Wien effect measurements in dilute soil suspensions. In the current study, energy relationships between heavy metal ions and particles of Hapli-Udic Argosol （Alfisol） and Ferri-Udic Argosol were inferred from Wien effect measurements in dilute suspensions of homoionic soil particles （〈 2 μm） of the two soils, which were saturated with ions of five heavy metals, in deionized water. The mean Gibbs free binding energies of the heavy metal ions with Hapli-Udic Argosol and Ferri-Udic Argosol particles diminished in the order of Pb^2＋ 〉 Cd^2＋ 〉 Cu^2＋ 〉 Zn^2＋ 〉 Cr^3＋, where the range of binding energies for Hapli-Udic Argosol （7.25-9.32 kJ mol^-1） was similar to that for Ferri-Udic Argosol （7.43-9.35 kJ mol^-1）. The electrical field-dependent mean Gibbs free adsorption energies of these heavy metal ions for Hapli-Udic Argosol and for Ferri-Udic Argosol descended in the order： Cu^2＋ 〉 Cd2^＋ 〉 Pb^2＋ 〉 Zn^2＋ 〉 Cr^3＋, and Cd^2＋ 〉 Cu^2＋ 〉 Pb^2＋ 〉 Zn^2＋ 〉 Cr^3＋, respectively. The mean Gibbs free adsorption energies of Cu^2＋, Zn^2＋, Cd^2＋, Pb^2＋, and Cr^3＋ at a field strength of 200 kV cm^-1, for example, were in the range of 0.8-3.2 kJ mo1^-1 for the two soils.

汉江上游郧县一级阶地发育土壤的诊断层特征及分类

阐明秦岭南侧北亚热带环境中黄土母质上发育土壤的诊断层特征及其分类意义。选择位于汉江上游郧县前坊村一级河流阶地土壤剖面为研究对象,对其粒度、磁化率、元素、矿物及结构进行了研究。结果表明,汉江河谷分布的土壤具有A-AB-Bt1-Bt2-BC-C剖面形态特征;Bt层具有"黏化层"的标志,并呈现黏磐的诊断特征,其黏化程度与中国典型黏磐湿润淋溶土有良好的可比性;黏土矿物以伊利石为主,少量高岭石,风化程度处在脱钙作用的后期阶段,尚未出现显著的富铝化作用,达到中等风化强度;土壤类型可归为黏磐湿润淋溶土。

商丹盆地黄土母质发育土壤的微形态特征及其诊断意义

阐明商丹盆地黄土母质发育土壤的微形态特征及其诊断意义。以茶房村土壤剖面为研究对象，在Lical 偏光显微镜下对土壤形成物、粗颗粒、孔隙等微形态单元的类型、空间分布及变化进行了研究。结果表明，与上部淋溶层和下部母质层相比，Bt 层（110~230 cm）黏土大量聚集且淀积黏土含量/残积黏土含量的比值（Ki/r）很高、但黏土胶膜不发育，粗颗粒数量减少、粒径降低孔隙个体增大，边沿更加平滑；矿物成分趋于单一。这些微形态特征证实了 Bt 属于典型的“黏化层”，结合成土因素检索，此土壤可归为简育湿润淋溶土。

黑龙江省虎林市漂白冷凉淋溶土土系划分研究

依据中国土壤系统分类所要求的分类原则和方法,按照统一的研究技术规范,对黑龙江省虎林市漂白冷凉淋溶土进行土壤调查和基层分类研究。研究结果表明:黑龙江省虎林市漂白冷凉淋溶土土类共划分3个亚类,进一步划分为黏质伊利石混合型冷性-潜育漂白冷凉淋溶土、黏质伊利石混合型冷性-暗沃漂白冷凉淋溶土、粗骨壤质混合型冷性-普通漂白冷凉淋溶土、黏质伊利石混合型冷性-普通漂白冷凉淋溶土4个土族,东方红系、虎林系、曙光系、复兴系4个土系。

丹江中游河谷黄土母质发育土壤的诊断特征及其系统分类研究

选择位于河南省南阳市淅川县荆紫关镇龙泉村丹江中游河谷黄土母质发育的土壤剖面作为研究对象,对其剖面构型及其色度、元素、粒度等理化性质进行了分析。结果表明,丹江中游河谷黄土母质发育的土壤具有Ap-Bp-Bt-Bw剖面形态特征;在剖面40-220 cm深度发生明显的黏粒富集,具有黏化层（Bt）的诊断特征;风化成壤强度达到中等风化强度阶段。剖面具有热性土壤温度状况和湿润土壤水分状况,在中国土壤系统分类中可划为耕淀简育湿润淋溶土。