خيارات البحث
النتائج 1 - 4 من 4
Comparison of soil thermal regimes in a deforested area with various grass cover in the Beskids Mts. [Czech Republic]
1998
Tuma, I. (Akademie Ved, Brno (Czech Republic). Ustav Ekologie Krajiny)
The studies of grass communities, which spread in deforested areas, also involved observations of soil thermal regimes. Three sites were chosen in order to determine differences in diurnal and seasonal variations of soil temperatures: (1) open site (barren) without plant cover, (2) site covered by a young, lower and thinner stand of Avenella flexuosa, and (3) old, dense stand of Calamagrostis villosa with a layer of plant litter on the soil surface. Soil temperatures were measured at the soil surface and in the soil depth of 5 and 10 cm. In summer months, the greatest differences in maximal temperatures recorded at the soil surface and at the 5, 10 cm depth between the bare site and the old stand of C. villosa represented 21.6, 15.9, 12.4 deg C, respectively. Soil temperatures measured in the bare plot in autumn months were lower than those in grass stands.
اظهر المزيد [+] اقل [-]Mineral soil nitrogen concentration in grass stands after deforestation
1998
Zahora, J. (Mendelova Zemedelska a Lesnicka Univ., Brno (Czech Republic))
Ammonium and nitrate concentrations in soil were determined in the initial stage of grass stand formation and in old closed grass stands (Avenella flexuosa, Calamagrostis villosa). Higher concentrations of both ammonium and nitrate ions were found in the 0-10 cm soil layer in comparison with the deeper soil layer of 10-20 cm. The amounts of NO3-N and water-soluble NH4+N generally represented only a small part of total mineral nitrogen in samples just removed. Presented data indicate seasonal fluctuations in ammonium and nitrate concentrations in soil.
اظهر المزيد [+] اقل [-]A study of the effect of the growth activity of grasses on accumulation and losses of organic matter and nutrients on deforested sites [Czech Republic]
1998
Fiala, K. | Tuma, I. | Holub, P. (Akademie Ved, Brno (Czech Republic). Ustav Ekologie Krajiny)
Effect of litter quality and environmental factors on decomposition of organic matter in grass stands of deforested areas in the Beskids
1999
Tuma, I. (Akademie Ved, Ceske Budejovice (Czech Republic). Botanicky Ustav)
