美国土壤盐度测定手段

美国土壤盐度研究所位于加里福尼亚州,隶属于美国农业部。该所有科研专家近40名,还经常有一批实习大学生参加研究工作。研究部门包括土壤及水化学室、植物室、土壤物理及工程室,主要从事水土保持、灌溉、土壤盐渍化及抗盐作物选育等方面的基础理论及应用技术研究。该所除拥有配备了先进仪器设备的实验室外,还有60块试验区。     

出露于夏威夷考爱（Kauai）岛上的双层盾形火山

出露于夏威夷考爱（Ｋａｕａｉ）岛上的双层盾形火山ＲｏｂｉｎＴ．Ｈｏｌｃｏｍｂ等盾形火山简单的外形常常掩盖其复杂的内部结构,由此导致对火山发育史的许多误解。自１８４０年ＪａｍｅｓＤ．Ｄａｎａ首次对夏威夷考爱岛调查以来,该岛一直被看作是单层盾形火山岛。该...     

流沙地铺设沥青隔水层防渗试验报告

新开垦流沙地的灌水和养分渗漏现象十分严重。为解决此问题,在土层50厘米深处辅设了-薄层不透水沥青层。试验表明,采取此种措施后,试验区的灌溉水量比对照区减少了50-60%;速效氮的淋溶损失也有减少。由于保水、保肥,促进作物产量提高。     

Matrix-bound phosphine in sediments from Lake Illawarra, New South Wales, Australia

Matrix-bound phosphine (MBP) has been measured in sediment from two cores in Lake Illawarra on the south east coast of Australia. The sediments were also dated in the upper layers. MBP concentrations found range from 142 to 1813 ng kg⁻¹, dw (dry weight of sediment) with some values being amongst the highest ever measured. Values of MBP in deeper sediments were higher than for near surface samples, but the patterns with depth were not consistent. Strong correlations were noted between MBP and organic phosphorus (OP, r > 0.8) and with total phosphorus (TP, r > 0.7), but only moderate correlations were found with organic carbon (OC, r > 0.5). No correlations were found between MBP concentrations and the age of the sediments. It was confirmed that high MBP concentrations are indicative of a phosphorus rich environment. The results tend to support the premise that MBP is generated by microbial attack on OP under anaerobic conditions.