青苔与对虾养殖的关系

青苔是一种丝状绿藻,颜色深绿。春季开始繁殖生长,早期如毛发一样附生池底。每当大雨过后,天气晴好,水温合适,青苔就大量繁殖,好似罗网悬张于水中,衰老时则成为棉絮状飘浮于水面,颜色呈黄绿色,手感发滑。 青苔对于对虾养殖有利的一面是:青苔本身可以作为对虾的饵料,虾苗很喜欢摄食青苔;     

Plant Community and Nutrient Status of the Soils of Schirmacher Oasis,East Antarctica

Investigations on plant community and micronutrient status of Schirmacher Oasis, East Antarctica have been presented in this paper. The dominant plant communities include moss and lichen. The frequency of species occurrence and changes in species composition at different location varied. Thirty-four soil samples were ana- lyzed for chemical properties of the soils of Schirmacher Oasis and Nunatak, East Antarctica. The most common plant species growing throughout the areas of Sehirmacher Oasis and Nunataks are： Candelariella tiara （ lichen ） and Bryum pseudotriquetrum （moss）. Large variations were observed among different soil samples in all the nutri- ents and other measured soil chemical parameters. The soils are characterized by a-cidic pH ranging from 4.42 - 6.80. The mean organic carbon content was 0.62 and ranged from 0. 06 - 1.29%. The electrical conductivity in 1 ： 2 soil water ratio ranged from 0.06 - 1.29. The average content of macronutrient cation, which are ammonium acetate extractable was in the order of Ca 〉 K 〉 Na 〉 Mg. The average content of DTPA extractable micronutrient cations was in the order of Fe 〉 Mn 〉 Cu 〉 Zn. Thirty one out of 34 samples contained less than 0.80 ppm DTPA extractable Zn. Correlation studies revealed that content of macronutrient cations significantly and positively correlated to that of chlorides. Electrical conductivity exhibited significant and positive relationship with pH, K, Ca, Mg, Na and chloride content. Sodium （r =0.876 ＊ ＊ ） exhibited highest correlation followed by K （r =0. 831 ＊ ＊ ） with chlo- ride content. The correlation coefficient for chlorides was higher with electrical conductivity （r=0.732＊ ＊ ） than pH （r =0. 513 ＊ ＊ ）. Organic carbon content of the soil was positively correlated with Fe （ r = 0. 442 ＊ ）. The nutrient status did not appear to be a limiting factor in growth of plants. Lichen and moss community structure and composition in the study area were not related with fertility status o     

应用扑草净杀灭虾池青苔的试验

１试验条件与方法１．１利用大型试验缸，水体０．２ｍ３，配制６个梯度的药液浓度，进行对对虾、文蛤的毒性试验。１．２利用圆玻璃缸，水体６５００ｍｌ，２０００ｍｌ，分别配制６个梯度的药液浓度，对青蛤、沙蚕作毒性试验。１．３利用底面积０．４ｍ２的试验缸，水深２０ｃｍ，缸底投放附着青苔的石板，然后按底面积计算，配制４个梯度的用药量，试验对青苔的杀灭效果。１．４本试验用的扑草净购于江苏省阜宁县施庄多种经营服务部。２试验结果见表１，２，３。３生产试验１９９１年乳山三虾场１０号池，由于提前纳水肥地方法不当，长起…