黔中地区水稻土的含硒量及其对糙米硒含量的影响

通过贵州开阳县水稻土硒含量特征和该区水稻硒含量之间关系的调查研究表明:开阳县水稻土水溶性硒含量高于一般水稻土水溶性硒的临界值(0.01μgg-1),这与该区的成土母质、地形等因素有关。富硒水稻土使水稻对硒的吸收增加,该县出产的稻米硒含量普遍比贵州省其它地区高,平均含硒量高于粮食硒的正常含量范围(0.04~0.07μgg-1)。水稻地上各部分含硒量存在差异,糠、秸秆中的含硒量高于糙米,糙米含硒量与土壤硒含量的相关性达极显著水平(r=0.7861*,P<0.05)。     

潮土区土壤有机质含量的趋势演变研究--以禹城市为例

通过分析山东省禹城市100个采样点1980年和2003年耕层土壤的有机质含量,研究了土壤有机质的时空变异特征,探讨了潮土区有机质含量的变化,形成了研究区1980年和2003年有机质含量空间分布图及1980~2003年有机质含量的空间变化图。分析了研究区有机质含量增加的原因。研究结果表明,该市目前土壤有机质含量平均为14.68g kg-1,比1980年的6.0g kg-1增加了8.68 g kg-1,年均提高0.38g kg-1。土壤表层含盐量的降低为土壤养分含量提高提供了条件。     

A downscaling method for distributing surface soil moisture within a microwave pixel: Application to the Monsoon '90 data

A downscaling method for the near-surface soil moisture retrieved from passive microwave sensors is applied to the PBMR data collected during the Monsoon '90 experiment. The downscaling method requires (1) the coarse resolution microwave observations, (2) the fine-scale distribution of soil temperature and (3) the fine-scale distribution of surface conditions composed of atmospheric forcing and the parameters involved in the modeling of land surface-atmosphere interactions. During the Monsoon '90 experiment, eight ground-based meteorological and flux stations were operating over the 150 km² study area simultaneously with the acquisition of the aircraft-based L-band PBMR data. The heterogeneous scene is hence composed of eight subpixels and the microwave pixel is generated by aggregating the microwave emission of all sites. The results indicate a good agreement between the downscaled and ground-based soil moisture as long as the intensity of solar radiation is sufficiently high to use the soil temperature as a tracer of the spatial variability of near-surface soil moisture.     

坤泥沟子水土流失原因、危害及防治对策

坤泥沟子已列入肇东市水土保持重点治理区。分析了该流域水土流失的原因、危害，提出了防治对策。     

运用乙炔抑制-静态土柱培养法测定旱地土壤氮素反硝化损失

介绍了测定土壤反硝化作用的乙炔抑制 -静态土柱培养法 ,并就其应用中的一些条件进行了说明 ,内容包括土柱的取样深度、土柱取样量、土柱培养方式及基本操作程序等。最后阐述了这一方法在北京郊区土壤上的使用情况。     

桩－土体系荷载传递特性和若干问题探讨

通过对大量的荷载传递测量资料进行分析，对桩与土体系荷载传递特性以及与之相关联的影响因素进行归纳总结；并基于荷载传递特性分析，对目前工程设计中若干不合理作法提出作者自己的看法     

土体的椭圆——抛物双屈服面模型及其柔度矩阵

本文证明了以经典塑性为基础的弹性模型的土体应力－应变柔度矩阵不能满足主对角线元素应占优的要求，为此作者提出了修正椭圆－－抛物双屈服面模型。     

某电厂煤港工程淤泥性土的工程特性研究

基于室内试验成果, 对台山电厂淤泥性土的分层、工程特性、ｗ 和ｅ 对主要物理力学指标的影响等方面作了较深入的分析, 对与淤泥性土的工程特性有关的岩土工程问题作了分析、评价。     

TWJ-1型土工试验微机采集处理系统的应用

ＴＷＪ－ １ 型土工试验微机数据采集处理系统的优势在于主机和采集仪两者合二为一, 其 功能为： 土工试验数据采集、土工试验数据处理、数据及成果的归档和管理、传感器标定及通 道测试。     

Effects of soil moisture stress on monoterpenes in loblolly pine

Monoterpene composition of xylem oleoresin in pole-size loblolly pine (Pinus taeda L.) was different between moisture-stressed and -unstressed trees during two test years. -Pinene concentration increased in stressed trees whereas -pinene, myrcene, and limonene decreased. Variations in camphene concentration with soil moisture stress were inconclusive. It increased with moisture stress in one test year and decreased in stressed trees during the other test year.