Response of runoff and soil loss to reforestation and rainfall type in red soil region of southern China

To evaluate the long-term effects of reforestation types on soil erosion on degraded land, vegetation and soil properties under conventional sloping farmland (CSF) and three different reforestation types including a Pinus massoniana secondary forest (PSF), an Eucommia ulmoides artificial economic forest (EEF) and a natural succession type forest (NST), were investigated at runoff plot scale over a six-year period in a red soil region of southern China. One hundred and thirty erosive rainfall events generating runoff in plots were grouped into four rainfall types by means of K-mean clustering method. Erosive rainfall type I is the dominant rainfall type. The amount of runoff and the soil loss under erosive rainfall type III were the most, followed by rain-fall type II, IV and I. Compared with CSF treatment, reforestation treatments decreased the average annual runoff depth and the soil loss by 25.5%–61.8% and 93.9%– 96.2% during the study period respectively. Meanwhile, runoff depth at PSF and EEF treatments was significantly lower than that in NST treatment, but no significant difference existed in soil erosion modulus among the three reforestation treatments. This is mainly due to the improved vegetation properties (i.e., vegetation coverage, biomass of above- and below-ground and litter-fall mass) and soil properties (i.e., bulk density, total porosity, infiltration rate and organic carbon content) in the three reforestation treatments compared to CSF treatment. The PSF and EEF are recommended as the preferred reforestation types to control runoff and soil erosion in the red soil region of southern China, with the NST potentially being used as an important supplement.     

Fenton试剂处理活性艳红印染废水的实验研究

采用Fenton试剂对活性艳红印染废水进行了处理。通过正交实验考察了反应时间、反应温度、双氧水/硫酸亚铁摩尔比以及pH对印染废水的色度及COD去除率的影响,确定了Fenton试剂处理废水的最佳条件。结果表明,随着反应时间的延长,色度及COD去除率增大,最佳反应时间为20 min;色度及COD的去除率随着反应温度的升高而增大,最佳反应温度为50℃。色度及COD的去除率在双氧水(30%)的用量与硫酸亚铁用量之比为1:3.1时,去除效果最好;最佳pH值为4.5。出水达到排放标准。此法具有去除率高,设备简单,占地面小,操作方便,不产生二次污染等优点。     

2006年春季东海近海海域赤潮高发区溶解态营养盐的时空分布

测定了2006年春季东海赤潮高发海域溶解态无机营养盐的分布和含量,并初步分析它们与赤潮的关系.结果表明,调查海区营养盐浓度较高,与国家一类海水水质相比,无机氮和无机磷的超标率分别为54%和34%,杭州湾附近海域富营养化程度比较严重.调查海域由于受沿岸长江等河流输入的影响,营养盐浓度自近岸向外海快速递减,等值线几乎与海岸线平行.另外初步分析了一次赤潮生长消亡过程中各种化学参数的变化情况.     

碳酸盐岩风化残积层红黏土的边坡稳定性

根据工程实例,分析了碳酸盐岩残积层红黏土风化壳的特征及红黏土的工程地质性质,并探讨了红黏土边坡的稳定性问题.     

Al-Cu双金属体系对活性艳红X-3B的脱色研究

以典型偶氮染料活性艳红X-3B为模型污染物,采用测定染料去除率、TOC去除率、苯胺生成量的方法及添加EDTA的对照试验,考察Al-Cu双金属体系对偶氮染料废水的脱色机理和脱色动力学.结果表明,在近中性条件下处理30min后脱色率就可达到83%左右;处理120min后脱色率高达96.4%,其中约为34%的色度去除是由于活性艳红X-3B被还原为苯胺,约为20%和30%的色度去除是由于铝离子混凝和铝刨花表面吸附.染料废水脱色是一个先大量吸附再进行内电解还原逐步降解的过程,铝离子的絮凝-吸附作用能有效促进色度的去除.脱色反应可视为表观一级反应,提高反应温度可以加快脱色速率.     

光照与东海近海中肋骨条藻(Skeletonema costatum)赤潮发生季节的关系

利用船基现场培养实验和模型计算的方法,研究了光照与东海近海春夏季均能发生中肋骨条藻赤潮的关系.结果表明,中肋骨条藻生长的最适光照强度(I_opt)随水温(t)的增加呈“慢升快降”的不对称“倒V”形变化特征,在25℃左右I_opt最大,为121.6 Ｗ·m^-R, I_opt-t 曲线符合Blanchard方程; 由东海海表水温计算的中肋骨条藻I_opt的季节变化特征与东海海面光照强度、海水透明度的季节变化基本同步(R^R=0.907±0.115, p<0.001),且滞后于海面光照强度2个月左右,这使春夏季海水中光照最适宜生长的水层均为全年最厚(6m左右).可见,中肋骨条藻对光照的适应性很强,海区海水光照的适宜性是春夏季均能形成大规模中肋骨条藻赤潮的重要原因之一.     

Ecology of reproduction of the red king crab

Conditions for reproduction of the red king crab Paralithodes camtschatica (Tilesius) on scallop plantations in Primorye have been studied. It has been found that the settling of larvae and the growth of juveniles to the size sufficient for their survival take place only in the cleanest water areas of Peter the Great Bay. Solar activity (expressed as the Wolfer number) is one of the most important abiotic factors affecting P. camtschatica reproduction. The population dynamics of juvenile crabs are characterized by fluctuations with two-year and five-year cycles.     

长江防护林——樟树林对降雨再分配的影响

林冠对降雨的再分配,是森林生态学和森林水文学研究的一个重要方面,其影响降雨从林冠到土壤的转移以及水土流失的变化,具有突出的生态水文意义。通过对樟树林下穿透雨和树干流的定位监测,旨在揭示林冠水文效应的变化规律,结果表明：林冠对降雨的再分配功能受到降雨量的影响,穿透雨、树干流和截留量与降雨量呈显著的正相关(〖WTBX〗P〖WTBZ〗<005);穿透雨率随着降雨量增加而增加,而截留率随降雨量增加而减小,并且两者在高的雨量下逐渐趋于稳定,但是树干流率随着降雨量增加先升高后降低。同时,降雨强度也影响林冠的水文效应,随着降雨强度的增加,穿透雨率升高,截留率下降。在整个测定期间,樟树林穿透雨率为685%,截留率为292%,而树干流率为23%。在不同雨量和雨强级间,樟树林冠对降雨再分配存在着差异,而且林内雨的组成比例（〖WTBX〗SF／TF〖WTBZ〗）也受到降雨量和降雨强度的影响。樟树林下水分输入存在明显的空间异质性,穿透雨率在不同位置间具有显著性的差异,而且穿透雨的空间变化率,即穿透雨率的变异系数（CV）随着降雨量或降雨强度的增加而减少。     

中高温条件下活性红KE-3B厌氧脱色特性和机理初探

以活性红KE-3B为例,考察了中高温条件下盐度、VFAs(挥发性脂肪酸)、污泥的吸附等对其厌氧脱色的影响,从产气量和生物气组分来探讨活性红KE-3B厌氧脱色的形式和程度,并对活性红KE-3B的厌氧脱色机理作初步探讨.结果显示,高温更有利于活性红KE-3B的脱色,脱色率可以达到98%以上,维持高脱色率的最高盐度为600mmol·L-1,并且在脱色过程中,没有发现活性红KE-3B被矿化,其主要脱色形式为初级降解.     

Influence of soil type and genotype on Cd bioavailability and uptake by rice and implications for food safety

Cadmium (Cd) entering the human body via the food chain is of increasing concern. This study investigates the effects of soil type and genotype on variations in the Cd concentrations of different organs of nine rice plants grown on two types of soils with two Cd levels. Cd concentrations in nine rice cultivars varied significantly with genotype and soil type (P < 0.01). The Cd concentration was higher in red paddy soil (RP) than in yellow clayey paddy soil (YP). The average Cd concentrations of different organs in three rice types were indica > hybrid > japonica for the Cd treatments and controls. The polished grain concentration in YP and RP soils had a range of 0.055-0.23 mg/kg and 0.13-0.36 mg/kg in the Cd treatment, respectively. Two rice cultivars in YP soil and five rice cultivars in RP soil exceeded the concentration limits in the Chinese Food Hygiene Standard (0.2 mg/kg). The Cd concentrations in roots, stems, and leaves were all significantly and positively correlated to that in polished grain in a single test. The Cd concentrations in polished grain were positively and significantly (P < 0.01) correlated with the calculated transfer factors of stem to grain and leaf to grain Cd transfer. The results indicated that the variations of Cd concentration in grain were related to Cd uptake and the remobilization of Cd from stem and leaf to grain. Also, the cultivars with a strong tendency for Cd-accumulation should be avoided in paddy soil with low soil pH and low organic matter content to reduce the risks to human health from high Cd levels in rice.