桉树人工林对林区水库黑水的影响

以桉树人工林区水库———南宁市天雹水库周边种植的桉树、马尾松两种主要树种为研究对象,分别对比其凋落叶在蒸馏水、水库表层水样、水库底层水样浸泡下的水质特征,并结合2018年春(3月)、夏(7月)、秋(11月)、冬(12月)4个季节对水库近桉树林与马尾松林径流入库区水质情况,分析桉树凋落叶对林区水库黑水的影响。结果表明:桉树浸泡液呈现黄棕色甚至黑褐色,色度显著大于马尾松浸泡液,其单宁酸与溶解性有机碳(DOC)质量浓度分别达到1.14 mg/L和46.40 mg/L,均较马尾松高,水体色度与DOC、单宁酸均呈显著正相关关系,相关系数分别为0.83和0.94;近桉树林区库区的水体的有机质和Mn质量浓度也高于近马尾松林区库区;桉树凋落叶与缺氧的水库底层水体混合后,Fe、Mn质量浓度升高,分别达到1.21 mg/L和2.09 mg/L。     

Measurement of monoterpene hydrocarbon levels in vapor phase surrounding single-leaf pinyon (Pinus monophylla Torr. & Frem.: Pinaceae) understory litter

A headspace air-sampling experiment was performed in the laboratory to determine the identity and concentrations of monoterpene hydrocarbons that could be attained in the vapor phase surrounding single-leaf pinyon pine (Pinus monophylla Torr. & Frem.) understory litter using controlled air collection conditions at a simulated field temperature of 37.8°C. The total monoterpene hydrocarbon content in 21 sequential samples of air collected from a sealed glass carboy packed with 1.44 kg of single-leaf pinyon litter equivalent to a bulk density of 0.15 g/cm³ averaged 3.56 ± 1.04 mg/liter. The monoterpenes-pinene and camphene were present in the vapor phase at the highest concentrations, averaging 2.40±0.64 and 0.68±0.22 mg/ liter, respectively. Myrcene,-pinene, 3-carene,-phellandrene, and-terpinene were all present at average concentrations below 0.30 mg/liter. The first two traps of the sequential air samples yielded the highest concentrations for the monoterpene hydrocarbons; however, the average total levels were relatively stable throughout the remaining 19 traps. Therefore, the data indicate that these hydrocarbons volatilize from the source pinyon litter and maintain an equilibrium in the vapor phase. Although this analysis was conducted using an artificial system, combined with results from our previous studies, mounting evidence indicates that monoterpene hydrocarbons present in the vapor phase of the single-leaf pinyon understory may be toxic to a variety of native plant species and thus further implicates allelopathy as a significant contributor to the observed patterning of associated vegetation in these forests.     

Larvicidal Effect of a Cell-Wall Fraction Isolated from Alder Decaying Leaves

Decaying alder leaves in water from Alpine Aedes breeding sites, particularly their toxicity to larval Culicidae, were investigated and characterized with comparative toxicological and chemical methods. Bioassays that used third-instar Aedes aegypti as a reference species indicated that the larvicidal effect of crude leaf litter varied with decaying age of the litter, while no toxicity was detected from leaching water of the mosquito breeding sites. Ten-month-old leaf litter was the most toxic. Comparison of the different soluble and insoluble fractions obtained after sequential extraction of decomposed litter allowed us to localize the toxicity factor to an insoluble cell-wall fraction. The toxicity seems to be linked to phenolic activity. It is higher than that found for tannic acid solutions used as a reference to mimic the larvicidal effects of the molecules naturally occurring in decaying litter. The pattern of establishing the larvicidal effect of alder leaf litter in water of Alpine Aedes breeding sites is discussed.     

Applications of poultry litter and triple superphosphate fertilizer to a sandy soil: effects on soil phosphorus status and profile distribution

To determine P loadings, added through poultry litter, sufficient to cause downward movement of P from the cultivated layer of a sandy soil, six rates of poultry litter were applied annually for four years to a site in central England. (total loading 0 – 1119 kg P ha^-1). A single extra plot also received an extra 1000 kg ha^-1 as triple superphosphate (TSP; total loading 2119 kg P ha^-1) and three other treatments received 200 – 800 kg ha^-1 P as TSP only. Annual soil sampling in 30-cm increments to 1.5-m depth provided information on P build-up in the topsoil and P movement to depth. There were strong linear trends between P balance (P applied – P removed in crops) and total P, Olsen bicarbonate extractable P and water-soluble P in the topsoil. Phosphorus from TSP and poultry litter fell on the same regression lines, suggesting that both would be equally effective as fertilizer sources. We calculated that 100 kg ha^-1 surplus total P would increase the Olsen extractable P content by c. 6 mg kg^-1 and the water-soluble P by c. 5 mg kg^-1. Thus, relatively large amounts of P would need to be applied to raise soil P status. We found some evidence of P movement into the soil layers immediately below cultivation depth. However, neither soil sampling nor soil solution extracted through Teflon water samplers showed evidence of movement into the deep subsoil (1 m) despite large P loadings.     

新型双胍类抗菌剂在硅胶猫砂中的应用研究

本文选用具有广谱、速效的聚(六甲撑基双胍)盐酸盐(PHMB)杀菌剂对多孔硅胶做处理,试制出了新型抗菌猫砂,并对其抗菌性能、抗致病菌和长效抗菌性进行了抗菌效果验证,实验结果表明:添加PHMB杀菌剂的新一代猫砂具有很好的杀菌效果,是一种理想的宠物垃圾清洁剂,改善了饲养者的家庭环境。     

坝上地区沙棘林枯落物层和土壤层的水文效应

通过以坝上高原典型区域尚义县的沙棘林地为研究对象,从林地枯落物蓄积量和持水能力,土壤物理性状、土壤蓄水量和土壤入渗性能等方面,对沙棘林枯落物与土壤的水文效应进行了研究。结果表明:沙棘林地枯落物的蓄积量为1.50×103kg/hm2,枯落物有效拦蓄量达到3.86×103kg/hm2,有效拦蓄深为0.39mm。与裸沙地相比,沙棘林下与林间0～40cm土层内的平均容重降低13.87%和4.05%,而总孔隙度较裸沙地增大13.95%和2.37%;沙棘林可增加土壤的有效持水量和饱和持水量,其林下与林间0～40cm土层内的有效持水量为裸沙地同层次的有效持水量的3.73倍和2.28倍。沙棘林间和林下的土壤初渗速率和稳渗速率分别是裸沙地的1.79倍、1.34倍和1.67倍、1.29倍。说明沙棘林能够较好地改善该地区的土壤结构,具有良好的水文生态功能。     

Comparative analysis of allelopathic effects produced by four forestry species during decomposition process in their soils in Galicia (NW Spain)

The development of toxicity produced by vegetable litter of four forest species (Quercus robur L.,Pinus radiata D.Don.,Eucalyptus globulus Labill, andAcacia melanoxylon R.Br.) was studied during the decomposition process in each of the soils where the species were found. The toxicity of the extracts was measured by the effects produced on germination and growth ofLactuca saliva L. var. Great Lakes seeds. The phenolic composition of the leaves of the four species was also studied using high-performance liquid chromatographic analysis (HPLC). It was verified that toxicity was clearly reflected in the first stages of leaf decomposition inE. globulus andA. melanoxylon, due to phytotoxic compounds liberated by their litter. At the end of half a year of decomposition, inhibition due to the vegetable material was not observed, but the soils associated with these two species appeared to be responsible for the toxic effects. On the other hand, the phenolic profiles are quite different among the four species, and greater complexity in the two toxic species (E. globulus andA. melanoxylon) was observed.     

杉木人工林凋落物量及其季节动态

对杉木人工林凋落物量进行了为期1 a的监测,研究结果表明:杉木人工林年凋落物总量为2 427.51kg.hm-2.在凋落物组成中,落叶占绝对优势,在凋落总量中其比例占的73.51%,其次分别为落枝(20.11%)、碎屑物(5.00%)、落果(1.07%)和树皮(0.31%).总凋落物量表现出明显的季节动态,在2月、5月和7月出现3个比较明显的峰值.     

The effect of different ceramic materials to improve hardness of organomineral fertilizer granules

Chicken litter (CL) is a waste generated by poultry farming and it that has increased significantly in recent years. Due to chicken litter levels of nitrogen, potassium, phosphorus, and other nutrients, the CL has a potential use as fertilizer, nevertheless, this purpose has been threatened by the pollution of water resources owing to the leaching and disposal of these nutrients. The production of CL granular organomineral fertilizers (OMF) is one way of minimizing these problems and to add value to poultry waste. Thus, this study evaluates the potential of the use of different binder materials on the improvement of the hardness and nutrient release. For this, five ceramic materials were added in four different concentrations to the powder mixture containing Monoammonium Phosphate (MAP) and CL. The fertilizers were granulated and through hardness evaluation, it was possible to observe that the positive effect on the hardness depended on the additive used and its concentration. The most promising additive was magnesium oxide that, was able to improve the strength of by up to four times, when compared to the OMF control. The results shown that the nutrient release is not affected with addition different binder materials.     

补充生物质强化水平潜流湿地去除硝酸盐氮研究

针对垂直流-水平流组合人工湿地的水平流段反硝化碳源不足的问题,研究了投加香蒲枯叶对去除硝酸盐氮及出水水质的影响.结果表明,投加经过碱处理和未处理的香蒲枯叶均可以提高水平潜流人工湿地系统对硝酸盐氮的去除速率.在进水硝酸盐氮为50 mg/L时,投加经碱处理的香蒲枯叶后,运行初期的出水硝酸盐氮<7 mg/L,去除速率可达12.18 S/(m~3·d);投加未处理的香蒲枯叶后,运行初期的出水硝酸盐氮<15 mg/L,去除速率为9.21 g/(m~3·d).投加香蒲枯叶后,系统出水总氮的变化趋势与硝酸盐氮的一致.