3种水稻土时间序列黏粒矿物的组合特征与物源指示意义

对南方丘陵区3种不同母质水稻土时间序列黏粒矿物的X-射线衍射（XRD）进行分析发现：① 紫色砂页岩（PS）母质起源土壤的黏粒矿物以高岭石类似矿物为主;第四纪红黏土（RC）母质起源土壤的黏粒矿物以高岭石类似矿物、伊利石类似矿物与三羟铝石为主;红砂岩（RS）母质起源土壤的黏粒矿物以1.4 nm过渡矿物、高岭石类似矿物与三羟铝石为主。② 这3种母质土壤种稻后黏粒矿物的变化大体可分为2种情况。RC与RS母质的起源土壤种稻后,土壤黏粒矿物的变化相对较小,伊利石类似矿物相对含量有所增加,这可能主要与钾肥的持续施用有关。PS母质的起源土壤种稻后,土壤黏粒矿物变化相对较大,表现为高岭石类似矿物相对含量降低,低结晶度的伊利石或次生绿泥石与三羟铝石相对含量上升。PS母质发育的土壤种稻后脱钾明显且主要集中在原生矿物部分。这种原生矿物的脱钾作用对土壤黏粒含量和黏粒矿物的类型都有较大影响。③ 起源土壤的黏粒矿物通常会被水稻土所继承,并在水稻土发育过程中相对稳定,可以用其来指示起源土壤（或母质）的物源组分。     

Lichen-dominated soil crusts as arthropod habitat in warm deserts

Soil crust lichens can be the dominant vegetation in arid lands, yet their importance as habitat to secondary producers is relatively unknown. This study examines the distribution of arthropod communities in the northern Namib Desert to evaluate whether a lichen-rich area is more or less productive than adjacent habitats in terms of the consumers each supports. Arthropods are diverse and highly endemic in the Namib Desert and lichens dominate this desert's extensive gravel plains. We sampled lichen-rich, dwarf shrub, and unvegetated sites and found distinct arthropod assemblages in the lichen-dominated sites, including species unique to lichen sites. Arthropod assemblages in two of the lichen sites were similar to those found in the dwarf shrub site. In a canonical correspondence analysis, crustose lichens and overall lichen cover were key in driving the variance in arthropod assemblages within the lichen sites. Furthermore, lichen morphotypes, overall lichen cover and species richness, were significantly correlated with the representation of arthropod subgroups and arthropod species richness. These findings provide evidence that lichen-dominated soil crusts in the Namib Desert are important supporters of secondary production, warranting more in-depth studies into the ecology and conservation of this lichen-rich habitat in warm deserts.     

粤东海涂土壤及其利用

粤东海岸东起闽粤交界的大埕湾,西迄深圳市的大鹏湾,岸线曲折,港湾较多,河溪人海泥沙在潮间带及紧邻5m 等深线以内形成大片海涂,土壤类型多样,以泥质和沙泥质土壤为主;除河口湾的土壤含盐量低外,其余较高;土壤有机质含量中等,钾素较丰富,磷素较低。因地处亚热带南缘,光、热和水资源条件较好,且多数海湾有深入内地的小海湾和潮沟,甚适合发展海水养殖与晒盐,韩江口的义丰河和海门龟头海大闸外等滩地尚有围垦价值。多处海湾潮滩沙土适合作海滨浴场,也有小片滩地红树林适合旅游观赏。     

Effects of Poplar Plantations on the Physical and Chemical Properties of Soils: A Case Study in the North China Plain

In recent years, large areas of farmland in the North China Plain have been converted into short-rotation poplar plantations. To analyze the impacts of poplar plantations on soil, 22 soil samples were collected and assayed from the soil profiles of a corn field and a poplar plantation. The results showed that the average soil moisture content of the soil profile in the poplar field was 2.6 percent lower than that of the arable land. The maximum difference in soil moisture content was found in the upper 0-10 cm of topsoil. Soil organic matter and nitrogen, phosphorus and potassium in the cornfield were significantly higher than in the poplar field. Higher nutrient content in the corn field may result from higher fertilizer inputs and the practice of returning straw to the cropped field. The analysis also showed no significant increase in soil organic matter content in deeper soil layers of the poplar field, which means that the conditions are not favorable for the formation of soil organic matter, or that soil organic matter needs a longer time to develop. Elements such as magnesium, iron, manganese and copper in both the corn field and the poplar field had a tendency to accumulate with increasing soil depth. Magnesium, iron, manganese and copper in the 0-80 cm soil layer of the poplar field were higher than those of the cornfield, but the situation was reversed at depths greater than 80 cm. It is concluded that poplar trees consume a large amount of soil moisture and soil nutrients. Local governments should prevent the development of new plantations of fast-growing trees in farmland and help farmers to recover their farmland from forestry plantations.     

黄土高原西部植物耗水实验研究

针对兰州地区8种常见植物的盆栽试验,比较了其耗水量的变化特征,结果表明：在充分供水条件下,8种植物在试验期间内都能正常生长,植物耗水量从大到小排序为：柽柳＞柠条＞芨芨草＞侧柏＞甘蒙锦鸡儿＞紫穗槐＞红砂＞珍珠;在集雨条件下,植物耗水排序为：芨芨草＞珍珠＞柠条、侧柏、甘蒙锦鸡儿、＞红砂、紫穗槐＞柽柳,但柽柳和紫穗槐在集雨条件下生长出现干枝,生长不好。在雨养条件下,除红砂、甘蒙锦鸡儿、珍珠受到干旱胁迫不明显外,其余植物不同程度上有枯叶出现。紫穗槐死亡,柽柳接近死亡,其他植物耗水排序为：珍珠、芨芨草＞侧柏、甘蒙锦鸡儿、柠条＞红砂。     

夏季晴空金塔绿洲温度场的初步分析

 利用2004年6~8月在甘肃省酒泉金塔地区开展的“绿洲—沙漠能量和水分循环的野外观测试验(JTEX)”的温度场资料,分析了该地区的温度场结构。结果表明:绿洲在白天（夜晚）相比周围环境是冷（暖）中心。沙漠和绿洲的相互影响同沙漠与绿洲的边缘和形状有关。由于各观测点所处的位置和站点的土壤特性不同,地表温度的量值有较大差别,但总体来说,绿洲的地表温度比沙漠的低;土壤温度的垂直变化一直可活跃到大约20 cm深处,40 cm深土壤温度基本无日变化,不同层间的土壤温度在一天内有两次相交。深度越深,出现的时间越靠后,沙漠上出现不同深度间温度交叉的时间比绿洲靠后。沙漠上各层的温度都始终高于绿洲上的,沙漠的日变化也大于绿洲上的。     

科尔沁沙地固定沙丘土壤水体积分数变化

利用2006-2009年5-9月科尔沁沙地固定沙丘0~150 cm土壤水体积分数监测数据及降水资料,采用偏度、峰度检验法检验了固定沙丘不同月及不同土层土壤水体积分数的正态性,并得到了其正态分布相关参数的估计值及其置信区间;同时,对不同土层、不同月及不同年间的土壤水体积分数变化和差异进行了分析。结果表明:(1)固定沙丘同一月的土壤水体积分数以显著性水平α=0.1通过正态分布的假设检验;固定沙丘土壤水体积分数的平均值范围1.82%~4.95%,主要集中在2%~4%;(2)受降水影响,固定沙丘7月土壤水体积分数较高,且与其他月的差异显著;7月土壤水体积分数均值和方差的点估计及置信水平为0.95的置信区间、统计特征均与其他月的有较大差异;(3)固定沙丘0~10 cm土壤水体积分数较低,且与其他土层有显著差异;而10~30 cm土壤水体积分数较高;(4)2008年土壤水体积分数较低,而2009年土壤水体积分数较高;除2007年与2008年土壤水体积分数没有显著差异外,其余年份间的土壤水体积分数均有显著差异。     

灌丛对川西北高寒草甸土壤资源的影响

以川西北高原红原县为研究区,用方格取样法,在相邻的高寒灌丛草地和高寒草甸样地中分别随机取0~20 cm土样50个,并分析了这些土样的土壤性状。利用SPSS(11.0)软件对实验数据进行了统计、分析和比较,研究了两个样地的各种土壤养分的平均含量、空间异质性和相关关系。结果表明,草甸样地的粘粒含量、Ptotal、Ntotal、ORG、Pavail、Navail、Kavail的含量都高于灌丛样地,且两样地速效养分差异极显著,但草甸样地土壤的ORG、Navail、Kavail的变异系数(CV)却明显小于灌丛样地,特别是Kavail的CV值,灌丛样地比草甸样地高出了53.37%;相关分析还表明,相对于草甸,灌丛样地中各养分元素之间的相关性明显增强。说明灌丛对高寒草甸土壤资源的异质性有明显的影响,其存在降低了草甸土壤养分的均值含量并增强了土壤养分的变异性和侵蚀潜力,不利于高寒草甸土壤养分的保持。     

山丘平原过渡区土壤重金属污染特征及评价——以四川省五通桥区为例

采集和分析了五通桥区不同功能区和乡镇73个土壤样品，以了解山丘平原过渡区土壤重金属的含量和污染特征。结果表明，重金属的平均含量为Pb32．18mg／kg、Cd0．82mg／kg、Cu28．61mg／kg、Zn108．08mg／kg、Ni32．66mg／kg、Cr72．44mg／kg；与四川土壤背景值相比，Cu、Ni、Cr的含量与之持平，Pb增加了0．11倍，Zn增加了0．32倍，Cd的积累较为严重，比背景值增加了10倍。污染评价结果显示该过渡区存在一定程度的重金属污染问题，不同功能区的污染程度排序为工业区〉生活区〉农业区。Cd在六种元素的土壤污染分担率中占55．46％，是最主要的污染元素；土壤Cd含量与Pb和Zn存在较高的相关性（相关系数为0．525和0．500），表明存在Pb—Cd和Zn—Cd的复合污染。     

大气CO2浓度升高对土壤中不同粒级碳的影响

不同粒级土壤中的碳有着不同的周转规律，在高CO2浓度条件下，它们含量的变化将在一定程度上反映土壤碳是累积还是减少，对明确土壤碳的变化趋势有重要意义．采用田间培养试验初步模拟研究在高CO2浓度条件下土壤不同粒级碳的分布．结果表明，加入秸秆培养1年，由于CO2浓度升高的原因导致在低氮（LN）、常规氮（NN）和高氮（HN）水平下土壤中碳分别增加0．01、1．10、1．22g／kg，表现为粒级〈53μm土壤颗粒中碳分别增加1．53、2．19、2．70g／kg．粒级〈53μmm土壤颗粒碳量的增加，主要是由于其重量分配百分数显著增加36．2％，碳浓度增加5．4％；粒级〉250μm和250～53μm土壤颗粒部分虽然其碳浓度分别增加20．8％和17．3％（P〈0．05），怛由于重量分配百分数分别显著降低22．8％和36．1％，结果碳量降低．试验表明高CO2浓度导致不同粒级土壤的分配及碳浓度的变化；高氮施肥水平下有增加土壤碳量特别是小粒级土壤碳量的趋势．