滴灌和施用秸秆降低日光温室番茄地氮素淋溶损失

以一年两季设施番茄为对象,利用渗漏池收集渗漏液,研究了设施菜地不同灌溉模式(滴灌、漫灌)和施用有机物料(单施鸡粪M、鸡粪配施玉米秸秆M+C、鸡粪配施小麦秸秆M+W)对土壤矿质态氮、可溶性有机氮淋溶损失的影响。结果表明,日光温室栽培条件下,氮素的淋溶损失主要发生于秋冬季,滴灌和漫灌模式下,该季可溶性总氮淋失量占全年淋失量的56.8%和71.1%。漫灌模式下,冬春季和秋冬季可溶性总氮淋失量分别为114.3和281.1kg/hm~2,占单季氮投入量的12.5%和29.3%。与漫灌相比,滴灌使全年番茄产量和氮素吸收量分别显著提高15.6%和21.4%,氮素利用率(氮素吸收量/氮素投入量)显著提高47.5%,同时使全年矿质态氮(铵态氮+硝态氮)和可溶性有机氮淋失量分别降低68.6和47.4 kg/hm~2,降幅分别为33.1%和39.6%。与单施鸡粪相比,鸡粪配施秸秆(玉米或小麦)对番茄产量无影响,但显著降低灌溉水渗漏量和氮素淋溶损失量,使全年灌溉水渗漏损失量平均降低24.3%,全年矿质态氮和可溶性有机氮淋失量分别平均降低26.6%和33.7%。综上,可溶性有机氮在氮素淋溶损失中不可忽视,滴灌模式通过降低渗漏液中氮的浓度,配施秸秆通过减少灌溉水的渗漏损失,进而降低可溶性氮的淋溶损失。     

德援项目森林可持续经营示范区建设成效调查

为了全面掌握德援项目森林可持续经营示范区建设完成情况,评价项目实施以来取得的成效,采用实地抽样调查方法对湖北省2005年以来实施的森林可持续经营示范区建设项目进行了调查。结果表明:林分结构得到明显改善,形成了由乡土树种组成的多树种混交结构和异龄林结构的近自然森林;森林植物种类明显增多,形成比实施前多5种以上的植物;森林质量显著提高,林木平均胸径增长50%以上,平均树高增长10%以上,平均每公顷蓄积增长50%以上;森林郁闭度保持在0.8~0.9,林地土壤腐殖质层厚达到10cm左右。示范区的示范效应突显,为项目区全面开展森林可持续经营提供了技术保障和科学依据。     

Rapid enzyme-linked immunosorbent assay and colloidal gold immunoassay for kanamycin and tobramycin in Swine tissues

A monoclonal antibody (Mab) was produced by using the kanamycin-glutaraldehyde-bovine serum albumin (Kan-GDA-BSA) conjugate as the immunogen. The anti-Kan Mab exhibited high cross-reactivity with tobramycin (Tob) and slight or negligible cross-reactivity with other aminoglycosides. The specificity and cross-reactivity of this Mab are discussed regarding the three-dimensional, computer-generated molecular models of the aminoglycosides. Using this Mab, a rapid enzyme-linked immunosorbent assay (ELISA) and a colloidal gold-based strip test for Kan and Tob were developed. The rapid ELISA showed a 50% inhibition value (IC 50) of 0.83 ng/mL for Kan and 0.89 ng/mL for Tob with the analysis time less than 40 min, and the recoveries from spiked swine tissues at levels of 25-200 microg/kg ranged from 52% to 96% for Kan and 61% to 86% for Tob. In contrast, the strip test for Kan or Tob had a visual detection limit of 5 ng/mL in PBS, 50 microg/kg in meat or liver, and 100 microg/kg in kidney, and the results can be judged within 5-10 min. Observed positive samples judged by the strip test can be further quantitated by ELISA, hence the two assays can complement each other for rapid detection of residual Kan and Tob in swine tissues. Moreover, physical-chemical factors that affected the ELISA and strip test performance were also investigated. The effect of pH and antibody amount for gold-antibody conjugation on the strip test sensitivity was determined followed by a theoretical explanation of the effects.     

Revealing the metabonomic variation of rosemary extracts using 1H NMR spectroscopy and multivariate data analysis

The molecular compositions of rosemary ( Rosmarinus officinalis L.) extracts and their dependence on extraction solvents, seasons, and drying processes were systematically characterized using NMR spectroscopy and multivariate data analysis. The results showed that the rosemary metabonome was dominated by 33 metabolites including sugars, amino acids, organic acids, polyphenolic acids, and diterpenes, among which quinate, cis-4-glucosyloxycinnamic acid, and 3,4,5-trimethoxyphenylmethanol were found in rosemary for the first time. Compared with water extracts, the 50% aqueous methanol extracts contained higher levels of sucrose, succinate, fumarate, malonate, shikimate, and phenolic acids, but lower levels of fructose, glucose, citrate, and quinate. Chloroform/methanol was an excellent solvent for selective extraction of diterpenes. From February to August, the levels of rosmarinate and quinate increased, whereas the sucrose level decreased. The sun-dried samples contained higher concentrations of rosmarinate, sucrose, and some amino acids but lower concentrations of glucose, fructose, malate, succinate, lactate, and quinate than freeze-dried ones. These findings will fill the gap in the understanding of rosemary composition and its variations.     

Chemical kinetic behavior of chlorogenic acid in protecting erythrocyte and DNA against radical-induced oxidation

As an abundant ingredient in coffee, chlorogenic acid (CGA) is a well-known antioxidant. Although some works have dealt with its radical-scavenging property, the present work investigated the protective effects of CGA on the oxidation of DNA and on the hemolysis of human erythrocytes induced by 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH) by means of chemical kinetics. The inhibition period (t(inh)) derived from the protective effect of CGA on erythrocyte and DNA was proportional to its concentration, t(inh) = (n/R(i))[CGA], where R(i) refers to the radical-initiation rate, and n indicates the number of radical-propagation chains terminated by CGA. It was found that the n of CGA to protect erythrocytes was 0.77, lower than that of vitamin E (2.0), but higher than that of vitamin C (0.19). Furthermore, CGA facilitated a mutual protective effect with VE and VC on AAPH-induced hemolysis by increasing n of VE and VC. CGA was also found to be a membrane-stabilizer to protect erythrocytes against hemin-induced hemolysis. Moreover, the n of CGA was only 0.41 in the process of protecting DNA. This fact revealed that CGA served as an efficient antioxidant to protect erythrocytes more than to protect DNA. Finally, the reaction between CGA and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS(+*)) or 2,2'-diphenyl-1-picrylhydrazyl (DPPH) revealed that CGA was able to trap radicals by reducing radicals more than by donating its hydrogen atoms to radicals.     

Input–Output Budgets for Inorganic Nitrogen Under Acid Rain in a Subtropical Evergreen Mixed Forest in Central-South China

Inorganic nitrogen deposition and leaching in stream water were monitored from January, 2001 to December, 2004 in a subtropical evergreen mixed forest in central-south China. The seasonal concentration and flux of inorganic nitrogen in bulk precipitation and stream water, seasonal mean net retention of nitrogen and net flux of H⁺ transformed by nitrogen were estimated and quantified in Shaoshan forest. The research results show that the correlation coefficient of fluxes between bulk precipitation and stream water is significant, with a coefficient 0.916 at the 0.01 level. Mean fluxes of inorganic nitrogen input are 2.62 g m^?2 a^?1 and 0.516 g m^?2 a^?1 in form of bulk precipitation and dry deposition respectively, and output in stream water is around 0.22 g m^?2 a^?1, which indicates that most of nitrogen input is reserved in the forest. Net retention of nitrogen reaches 2.916 g m^?2 a^?1, just higher than other study plots over the world. Along with the translating of nitrogen ( ${\text{NH}}_4^ + - {\text{N}}$ and ${\text{NO}}_3^ - - {\text{N}}$ ), H⁺ is imported to the forest ecosystem at the same time. At our study plots, net flux of H⁺ transformed by nitrogen is about 73.57 mmol m^?2 a^?1. The positive value suggests that Shaoshan forest is still a finer buffering system to nitrogen deposition and it is far from nitrogen saturation in spite of the high nitrogen deposition.     

Soil development along primary succession sequences on moraines of Hailuogou Glacier,Gongga Mountain,Sichuan, China

Soil properties related to soil development were measured in six profiles over approximately 180 years of soil development on recessional moraines of the Hailuogou Glacier, Sichuan of southwestern China. It is hypothesized that soil development is strictly time-dependent. Field and laboratory work indicate that as soil develops from initially coarse gravel outwash, the properties undergo a progressive physical and chemical change such that there is a considerable profile differentiation between the youngest and the oldest soils. The pH is also highly stratified; it decreases with time from 8.5 to 4.2 in the upper mineral soil and increases with depth in all profiles. Accumulation of soil organic C and N increases with time but the rates of accumulation become slower with time. Within the investigated timespan, soil C and N accumulated to a considerable level of 3.5 and 0.6 kg/m² respectively, with mean annual rates of 28 g/m² for carbon and 3.5 g/m² for nitrogen. The rapid accumulation of organic C and N accelerates the processes of soil formation, but the content of organic C and N did not reach a steady-state during the observed timespan. The accumulation of soil organic matter results in increased acid production and in the chemical weathering of minerals that promote formation and translocation of the clay fraction and leaching of carbonate; it is also directly responsible for development of soil properties such as cation exchange capacity (CEC), and bulk density.     

聚合物包膜肥料铵态氮释放特征研究

采用单一组分与复合组分的聚合物包膜肥料,利用静态水溶出的方法研究了不同温度和半径处理下,聚合物包膜肥料铵态氮释放特征。结果表明,养分释放显著受到温度、颗粒半径的影响,温度越高,半径越小,养分释放速度越快,且发现养分释放特征与肥芯的化合物组成有关,肥芯化合物组成不同造成各种离子的饱和浓度发生变化,影响了跨膜释放的动力从而影响释放。养分释放的滞后期和线性期也随温度的升高和颗粒半径的缩小而缩短,且肥芯化合物组成也通过影响离子的饱和浓度影响了养分释放的滞后期和线性期。利用养分释放活化能来反映养分释放速度变化随温度变化的敏感程度。试验结果表明,活化能与颗粒半径、肥芯化合物组成有关。通过对活化能和养分释放三阶段的描述能更全面地反映包膜肥料养分释放与作物养分需求的协调性,为包膜肥料的研制和应用提供了新的思路。     

基于GIS的县域耕地测土配方施肥技术研究

该文以山东广饶县为例,进行了面向管理层面的县域耕地测土配方施肥技术研究.在耕地地力调查分析数据及其地力评价的基础上,采用GIS支持下的"地力分区 目标产量法"确定区域施肥配方.以耕地地力等级图和作物布局图叠加的方法划分配方单元,通过田间试验得到各种参数,通过GIS将配方单元图与相应属性数据模型的联结,采用养分平衡法计算各养分需要量和施肥配方.结果显示,广饶县耕地氮、磷、钾养分含量空间分布差异较大,得到的施肥配方种类较多,全县共有14种施肥配方,其中氮磷钾配方比例分布在1:0.04～1.53:0.05～0.82之间.该研究较好地探索了基于GIS的县域耕地测土配方施肥技术方法,对县域耕地利用和施肥管理工作有积极的指导作用.