3种植物提取剂对土蜗杀灭效果的初步研究

初步研究了大蒜、苦楝、苦参3种植物的提取物室内浸杀土蜗的效果,结果表明:浓度为8mg/L的大蒜提取液48h的杀螺率达到70%,苦楝提取液浓度为80mg/L时48h的杀螺率达90%,浓度为22.4mg/L的苦参提取液96h的杀螺率达90%;大蒜、苦楝、苦参提取液浸杀土蜗48h的LC50分别为4.96mg/L、37.46mg/L、45.60mg/L,其杀灭土蜗的效果为:大蒜>苦楝>苦参。     

固相萃取–高效液相色谱测定水稻中的洛克沙胂

通过对超声提取法中提取剂、固相萃取中淋洗液和洗脱剂、高效液相色谱中流动相的筛选,建立固相萃取–高效液相色谱定量检测水稻中洛克沙胂的方法。所建方法为：样品先经0.05 mol/L NaOH+20 g/L K2HPO4超声提取;再利用活化后的固相萃取小柱,依次采用1.5 mL 0.05 mol/L乙酸钠–甲醇溶液(pH=7)和1.5 mL甲醇淋洗及体积分数为13%的甲酸–甲醇溶液洗脱;最后利用以含0.3%甲酸的0.05 mol/L磷酸二氢钾溶液和甲醇(体积比80∶20)为流动相的高效液相色谱进行定量分析;该方法在洛克沙胂质量浓度为0.01~10.00 mg/mL时线性关系良好,相关系数大于0.999,检测限和定量限分别为20、67 ng/kg;洛克沙胂在水稻根、茎、叶、壳、米中的加标回收率分别为80.0%~87.2%、74.0%~80.6%、80.0%~83.7%、81.0%~90.0%和83.2%~92.7%,相对标准偏差分别为2.2%~5.9%、2.4%~4.6%、2.0%~2.6%、3.6%~5.7%和3.2%~5.5%。     

酸性土壤有效砷提取方法研究

采用0.5mol·L-1NaHCO3(pH8.5),0.5mol·L-1NaH2PO4和0.1mol·L-1HCl等3种浸提剂,对福建省酸性水稻土和酸性菜地土壤有效砷的提取效果以及相关的提取条件进行了研究。结果表明,3种浸提剂所提取的土壤有效砷与作物可食用部分砷含量之间均存在显著相关,其中0.5mol·L-1NaH2PO4提取的有效砷与糙米和蔬菜地上部砷含量的相关性最高,相关系数分别是0.628和0.824,是三者中最佳的浸提剂。对NaH2PO4的提取条件的研究表明,在15∶1的液土比条件下以250r·min-1的速度振荡120min是最佳的酸性土壤有效砷的提取方法。     

Effect of Citrate Concentration on the Extraction Efficiency of Selected Micronutrients from Soil

This study was carried out with the objective of evaluating the effect of citrate concentration on the extraction efficiency of some micronutrients from soil. Composite surface soil samples (0–20 cm) were collected from Eastern Harage Zone (Babile and Haramaya Districts), Wolaita Zone (Damot Sore, Boloso Bombe, Damot Pulasa and Humbo Districts) and Dire Dawa Administrative Council in purposive sampling. The treatments were arranged in completely randomized design (CRD) with three replications. A greenhouse pot experiment with soybean plant was conducted to determine the correlation between soil test methods and the selected micronutrients, such as iron (Fe), copper (Cu), manganese (Mn) and zinc (Zn) in the leaves of the plant. The results showed that, among the different citrate concentrations with strontium chloride (SrCl₂) tested for the determination of available Fe, Mn and Zn, the highest correlation coefficients (r = 0.82, p < 0.05), (r = 0.96, p < 0.001) and (r = 0.98, p < 0.001) were found between the diethylenetriamine pentaacetic acid (DTPA) method and 0.02 M strontium chloride (SrCl₂)-0.025 M citric acid extractant, respectively. Therefore, 0.02 M SrCl₂-0.025 M citric acid extractant is considered to be the most effective for the determination of Fe, Mn and Zn in soils of the studied areas. Similarly, high correlation coefficients (r = 0.97, p < 0.001) were found between DTPA and 0.02 M SrCl₂-0.05 M citric acid and (r = 0.88, p < 0.01) between DTPA and 0.02 M SrCl₂-0.025 M citric acid extractants for the determination of available Cu from soils. Hence, the 0.02 M SrCl₂-0.05 M citric acid extractant was shown to be the best for the determination of Cu in soils of the studied areas. However, considering the use of universal extractant, the 0.02 M SrCl₂-0.025 M citric acid extractant could easily be adopted as a procedure for the determination of Fe, Cu, Mn and Zn for both agricultural and environmental purposes. The greenhouse experiment confirmed the result.     

Extractants for available boron in limed acid soils and its correlation in crops with high carbon storage capacity (Tectona grandis)

The objective of this work was to evaluate the efficiency of six extractants for available boron in acid soils undergoing to liming, and to correlate the results of soil analysis with foliar response seen in the teak plants in greenhouse conditions. Acid soil samples were collected and their chemical characterization was performed using standard analysis protocols. Later, agricultural lime was added to the experimental units in greenhouse conditions in order to control the soil acidity and these were incubated for 30 days. Six extracts for available boron were evaluated and correlated with response in the plant by foliar analysis. It is concluded that a high dissolution power of boron extractant solution produces a high sensitive in the determination of the changes of boron concentration in the limed acid soil. These methods are seen to be not adequate for the determination of available boron contents at high concentrations.     

4种花椒提取物对玉米象成虫熏蒸活性的研究

在30℃下采用广口瓶密闭熏蒸法熏蒸48h和72h,测定青椒精油、红椒精油、一级麻素及二级麻素时玉米象Sitophilus zeamais Motschulsky成虫的熏蒸致死作用及LC50值。结果表明LC50值大小顺序为一级麻素〉二级麻素〉红椒精油〉青椒精油．进一步研究熏蒸时间和温度时青椒精油及红椒精油熏蒸活性的影响,结果表明熏蒸时间越长,LC50值越小;温度越高,校正死亡率越大,表明2种花椒精油的持效期较长,在高温下能更好地发挥药效。     

Mehlich3法在新疆棉花土壤养分分析中的应用

[目的]评价Mehlich3法(以下简称M3法)测定新疆棉区土壤速效有效磷、钾、铜、锌、锰等的可行性.[方法]用Mehlich3通用浸提剂测定新疆石灰性土壤中有效养分,对目前较普遍适用于棉花土壤的浸提方法与M3法相比较.[结果]两种方法浸提棉花土壤有效态P、K、Cu、Zn、Mn含量的相关性均达到极显著水平,相关系数分别为0.936 6、0.903 2、0.8446、0.785 6和0.977 6;M3浸提剂测得各元素有效态含量均高于常用浸提方法测得各元素有效态含量,其中有效Mn的相差是最大的,达3倍,而Zn的结果相差不大.[结论]对M3方法及电感耦合等离子体光谱仪(ICP)精密度测定后认为M3方法结合ICP测定精密度高,结果稳定可靠.     

Evaluation of Soil Tests for Plant‐available Mercury in a Soil–Crop Rotation System

A reliable soil test is needed for estimating mercury (Hg) availability to crop plants. In this study, four extraction procedures including 0.1 M hydrochloric acid (HCl), 1 M ammonium acetate (NH₄OAc) (pH 7.0), 0.005 M diethylenetriaminepentaacetic acid (DTPA), and 0.1 M calcium chloride (CaCl₂) (pH5.0) were compared for their adequacy in predicting soil Hg availability to crop plants of a rice–cabbage–radish rotation system. The amounts of Hg extracted by each of the four procedures increased with increasing equilibrium time. The optimal time required for extraction of soil Hg was approximately 30 min, though it varied slightly among the four extractants. The amounts of Hg extracted decreased with increasing soil/solution ratio, and a soil/solution ratio of 1:5 appeared to be adequate for soil Hg availability tests. The amounts of Hg extracted increased in the order of NH₄OAc < CaCl₂ < DTPA < HCl in silty loam soil (SLS) soil, and the order was NH₄OAc < CaCl₂ ≈ DTPA < HCl in yellowish red soil (YRS) soil. Significant positive correlations among the four extractants were obtained in SLS soil. In contrast, the correlations were poor in YRS soil, especially for HCl. There were significant correlations between concentrations of Hg in edible tissue of three plants and the amounts of soil Hg extractable to the four extractants for soil–rice system and soil–radish system, but not for soil–Chinese cabbage system. The 0.1M HCl extraction overall provided the best estimation of soil‐available Hg and could be used to predict phytoavailability of Hg in soil–crop systems.     

Determination of Appropriate Soil Test Extractant for Available Phosphorus in Southwestern Nigerian Soils

Evaluation of five soil phosphorus (P) extractants was done on southwestern Nigerian soils from sedimentary and basement complex parent materials to determine the relationship between the extractants and the most appropriate extractant for the soils. The soils differed in properties. Generally, soils from the basement material had less available P compared with sedimentary material. Olsen extracted the greatest P. Bray 1 measured 67% of Olsen P, Hunter measured 52%, Mehlich measured 42%, and Ambic measured 24%. Positive and significant regression (P < 0.001) existed among Bray 1, Olsen, Mehlich, Hunter, and Ambic extractants. The strongest relationship was found among Olsen, Mehlich, and Ambic P. The relationship between maize P uptake and extracted P was quadratic, whereas the relationship with Mehlich was logarithmic. Bray, Mehlich, and Olsen P were the significant contributors to the maize P uptake and dry-matter yield. Extractants in order of P extraction were Olsen > Bray 1 > Hunter > Mehlich > Ambic.     

Mehlich3通用浸提剂测定石灰性土壤中有效养分的研究

用Mehlich3通用浸提剂测定了山西石灰性土壤中有效养分,与常规方法进行了比较和相关性研究,结果表明:Mehlich3法与常规法测定的土壤大量元素与微量元素其测定值呈极显著或显著正相关,并拟定了石灰性土壤大量元素与微量元素Mehlich3通用浸提剂的分级标准,Mehlich3通用浸提剂适用于山西石灰性土壤P、K、Mg、Na、Cu、Zn、Fe、Mn的测定。