Microelements in Potato and Lily Samples Studied by Laser-Induced Breakdown spectroscopy Technology

A LIBS setup was built in the Institute of Modern Physics. In our experiments, LIBS spectra produced by infrared radiation of Nd : YAG nanosecond laser with 100 and 150 mJ pulse energy, respectively, were measured by fiber optic spectrometer in the ranges of 230-430 run and 430-1080 nm with a delay time of 1.7 and gate width of 2 ms for potato and lily samples prepared by vacuum freeze-dried technique. The lines from different metal elements such as K, Ca, Na, Mg, Fe, Al, Mn and Ti, and nonmetal elements such as C, N, O and H, and some molecular spectra from C-2, CaO, and CN were identified according to their wavelengths. The relative content of the six microelements, Ca, Na, K, Fe, Al, and Mg in the samples were analyzed according to their representative line intensities. By comparison we found that there are higher relative content of Ca and Na in lily samples and higher relative content of Mg in potato samples. The experimental results showed that LIBS technique is a fast and effective means for measuring and comparing the contents of microelements in plant samples.

沈阳地区水灾后“被淤”农田土壤肥力状况及改良途径

<正> 1 引言沈阳地区位于辽宁省中北部,属中温带受季风影响的半湿润大陆性气候。该地区地貌类型多样,东北和西南紧靠长白山余脉千山山脉,属低山丘陵,中西部是辽阔平原地貌由东北向西南倾斜。全地区有大小河流15余条,大部向西南的辽中、新民等地汇集再出境入海,上游是旱坡地,而且林地的森林覆盖率较低。1995年7～8月,沈阳地区连降大雨,达658.3mm,相当于27a的全年平均降雨量的总和,造成百年不遇的特大洪水,致使平原地区大片农田被淹达20d左右,面积达6.67×10~5hm~2。这次洪水源于天然降雨并汇集上游地区地表径流而形成的,水体混浊,悬浮物