A possible EFFECT OF THE GLOBAL CLIMATE CHANGES ON SOIL. of view

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Marie Horáčková
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1 Soil Science topic No. 5: A possible EFFECT OF THE GLOBAL CLIMATE CHANGES ON SOIL an approach based on a soil scientifical point of view

2 Key approach From soil scientific view, the present global climate changes can be seen as a standard part of Holocenic development within the interglacial period, however, accelerated by human activities. Based on findings on climatic course in past interglacial periods, a less stable course of climate can be expected in coming centuries as a foreshadow of coming glacial time.

3 The HaDCH2 climate change model, elevated CO 2 model (SRES A2) and assesment on their likely impacts on forest soils in the Czech Republic What is dealing with: Changes in soil nutrition status Changes in water status Changes in slope stability status

4 Notes

5 A. Changes in soil nutrition status

6 The colloids, the inorganic and the organic stores of plant nutrients Plants affect soil by : Quantity and quality of their dead tissues Formation of specific moisture and temperature on the site Soil surface protection

7 Higher CO 2 concentrations will lead to higher input of biomass on mineral soil higher temperature will result in higher biological activities of soil heterothrophs higher activity of soil biota refers to acceleration of CO 2 production an increase in living biomass will result in increase in dead plant tissues content.

8 If there is a tendency for higher organic matter turnover, there is higher demand for available nitrogen higher biological activity in soil will lead to higher degree of nutrient release. Higher base saturation and more free available ions in soil solution will follow. Humic acids consisted of higher molecular weight molecules will be found more commonly.

9 The severe stress will be more harmful on shallow, non humic, sandy soils leading to greater differences among sites close to one another. Notes

10 New organomineral complexes will make soil fertility better on primarily fertile sites whereas a depletion of primarily poor sites can limit markedly productive capacities of acid or extreme sites.

11 Higher temperatures would result in higher rate of feldspare weathering by an influence of both mechanical and markedly stronger biological weathering, i.e., intense weathering in higheratmospherictemperaturesand speedy biological attacts of parent rocks. New soil colloidal grade and a new soil mineral nutrients richness will be result of a new forest phytocoenoses status as a primary results of higher atmospheric temperatures and CO 2 concentrations, both higher output of CO 2 from more massive accumulation of dead soil organic matter will be accompanied by an enhanced in clay mineral creation

12 More intense decompositions and higher input of plant dead organic matterwillmakefertilesoils fertiler and poor soils more exhausted.

13 Notes

14 B. Changes in water status

15 The soil water, its redistribution throughout seasons and vegetation types: a possible role of global climate changes If a role of soil water in the time of local climate changesisevaluated, what has to be mentioned first the HadCH2 climate change model and SRES A2 count on dramatic decline of presipitation rate in spring period.

16 Theincreasein atmospheric temperatures set about an increase in length of vegetational period and the increase in carbon dioxide concentrations se about an augmentation in productive abilities of tree speciesthe higher atmospheric temperatures in spring would result in higher evapotranspiration and new symptoms of spring drought can occur the spring drought can effect as an effective factor which fatal ecological on some tree species

17 Considerable changes in distribution of precipitation throughout the year with very prominent peaks. Usually high precipitations would be one of the most dangerous reasons for massive slide movements. Higher hydrostatic pressure, decrease of cohesion, new course of eloctroosmotic processes and desiccating or shrinking clayey soils in periods of drought.

18 Notes

19 C. Stability on slope i.e. changes in slope stability status

20 The slope movements, changes in water content and a decrease of cohesion: a possible role of global climate change Different kinds of slides have been provoked by diverse factors such as moving ground water, a change of slope gradient, vibrations and earthquakes, the exces load and, of course changes in water content in soil on a slope.

21 Where there can be expected the fenomena The most dangerous situation due to the disturbence of slope stability in: i) Bohemia will be found in the Cretaceous Table where sandstone slope debris combined with basalt blocks lies on clayed marl, ii) in Silesia glaciofluvial sediments in Ostrava region are in leopardy greatly, iii) but the worst situation will be probably in Moravia, where changes in stability of slopes within flysch belt in Western Outer Carpathian should be considered as really challenging.

22 Nevertheless, minimally me I am of optimistic belief in a future thus I do not believe in such change of the current forests...

23 Notes

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