Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài:Effects of sulfuric acid and nitrogen deposition on mineral nutrition of Picea abies (L.) Karst. | 599s Ann. Sei. For. 1989 46 suppl. 599s-603s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Effects of sulfuric acid and nitrogen deposition on mineral nutrition of Picea abies L. Karst. . Schneider M. Kaupenjohann and w. Zech Lehrstuhl fur Bodenkunde und Bodengeographie der Universităt Bayreuth Postíach 101251 D-8580 Bayreuth . Introduction Since 1980 Mg deficiency in spruce ecosystems of the NE-Bavarian mountains has caused needle yellowing and subsequent dieback of trees growing on soils low in base saturation Zech and Popp 1983 . At an altitude above 700 m Mg content of current year needles hardly exceeds of dry weight. N needle contents range between and which is a sufficient supply. Ca K and Zn concentrations are low whereas s concentrations of more than of dry weight are extremely high corresponding to the high SO2-content of the air in this region Zech eta . 1983 . The proton input of about kmol ha a-1 Kaupenjohann 1989 measured on experimental sites in the Fichtel-gebirge and low fogwater pH Trautner 1989 of indicate a high acid stress for forest ecosystems. In fogwater NH4 concentrations may also be extremely high up to meq-H Trautner 1988 . Total N deposition of 20-30 kg ha a-1 exceeds the N demand of trees and high amounts of nitrate are washed out of the soils Hantschel 1987 . To study the effects of air pollutants on spruce ecosystems saplings have been sprayed with artificial acid rain structured soil samples have been extracted with sulfuric acid and the effects of high NH4 inputs on tree nutrition have been measured close to a chicken farm. Materials and Methods Sulfuric acid treatment of spruce sapling Seedlings 3 yr old growing in a nutrient solution were sprayed 3 times a day with ml of H2SO4 pH or deionized water pH 5 6 during a 10 day period Kaupenjohann et al. 1988 . Sulfuric acid treatment of naturally structured soil samples Naturally structured soil samples 100 cm3 were .
