10 research outputs found
Long-term forest soil acidification, nutrient leaching and vegetation development: Linking modelling and surveys of a primeval spruce forest in the Ukrainian Transcarpathian Mts.
The biogeochemical model MAGIC was applied to simulate long-term (1880–2050) soil and stratified soil solution (30 and 90 cm depth) chemistry at a spruce dominated site in the western Ukraine (Pop Ivan, 1480 m a.s.l.) to evaluate the effects of acid deposition on soil acidification in a less polluted region of Europe.
Since 2008, sulphur (S) deposition of 9 kg ha−1 year−1 and nitrogen (N) deposition of 8.5 kg ha−1 year−1 have been measured at Pop Ivan. The recent deposition of S and N is about 30% and 50% of those values estimated for the early 1980s, respectively. Acidic deposition caused the depletion of base cations (Ca, Mg, Na, K) from the soil cation exchange complex, which resulted in a decrease of calcium and magnesium saturation between 1935 and 2008 in the top mineral soil (0–30 cm) and deeper mineral soil (30–80 cm) by 67% and 88%, respectively. Base cation leaching acted as the major buffer mechanism against incoming acidity, therefore the measured inorganic aluminium (Al) concentration in soil solutions is ca. 10 μmol L−1 and the subsequent molar (Ca + Mg + K)/Al ratio above 1. Recovery of the soil solution pH and Al is expected within the next 40 years, whereas the soil base saturation will only increase slowly, from 6% to 9.8% in the top soil and from 5.5% to 11% in the deeper mineral soil. Since the 1960s, modelled inorganic N leaching (as NO3) has started to increase following the trend in N deposition. Modelling and experimental evidence suggest that N availability from mineralization and deposition exceeds the rate of microbial and plant immobilization. Thus, soil N accumulation since the 1960s has been limited. A significant increase in nitrophilous species as well as a decrease of herb layer diversity was observed between 1936 and 1997
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Calcium availability affects the intrinsic water-use efficiency of temperate forest trees
Acknowledgements: We are thankful to Natálie Pernicová and Inna Roshka, who contributed to preparing plant samples. This study was supported by the Czech Science Foundation (GACR No. 20-19471S) and partly by GACR No. 23-07583S (conceptualization during the project preparational phase). We acknowledge the SustES project—Adaptation strategies for sustainable ecosystem services and food security under adverse environmental conditions (CZ.02.1.01/0.0/0.0/16_019/0000797).AbstractIntrinsic water-use efficiency (iWUE) of trees is an important component of the Earth’s coupled carbon and water cycles. The causes and consequences of long-term changes in iWUE are, however, still poorly understood due to the complex interplay between biotic and abiotic factors. Inspired by the role calcium (Ca) plays in plant transpiration, we explore possible linkages between tree ring-derived iWUE and Ca availability in five central European forest sites that were affected by acidic air pollution. We show that increasing iWUE was directly modulated by acid air pollution in conjunction with soil Ca concentration. Responses of iWUE to rising atmospheric CO2 concentrations accelerated across sites where Ca availability decreased due to soil acidity constraints, regardless of nitrogen and phosphorus availability. The observed association between soil acidity, Ca uptake, and transpiration suggests that Ca biogeochemistry has important, yet unrecognized, implications for the plant physiological upregulation of carbon and water cycles.</jats:p