Ekologiczna rola prochnicy glebowej

W pracy omówiono główne funkcje próchnicy glebowej w środowisku przyrodniczym. Specjalną uwagę poświęcono udziałowi próchnicy w tworzeniu gleb i kształtowaniu ich właściwości, a mianowicie w procesach sorpcji, ruchliwości jonów metali w glebie, wiązaniu pestycydów i regulowaniu właściwości buforowych gleb. Przedyskutowano również zagadnienia dotyczące roli próchnicy jako źródła energii i składników pokarmowych dla drobnoustrojów glebowych, a także problem bezpośredniego oddziaływania związków humusowych na mikroorganizmy glebowe i rośliny.In the paper the main functions of soil organic matter in the environment are discussed. The special attention is paid to participation of soil organic matter in soil formation processes and properties: the role of soil humus in sorption processes, metal ions mobility, pesticides bonding and soil buffering regulation. The significance of soil humus as a source of energy and nutrients for soil microorganisms and direct effects of humic substances on microorganisms and plants are also discussed

Zaleznosc miedzy rozdrobnieniem prochnicy w poziomie organicznym mor a niektorymi jej wlasciwosciami

Celem pracy było zbadanie zależności między frakcjami rozdrobnienia próchnicy typu mor a jej właściwościami wynikającymi z procesów transformacji (mineralizacji i humifikacji). Rozdrobnienie i zawartość materiału organicznego w poszczególnych frakcjach ilustruje rysunek 1. Stwierdzono, że ze wzrostem rozdrobnienia próchnicy (szczątków organicznych) wzrasta zawartość materiału mineralnego (rysunek 1, tabela 3), stopień humifikacji (rysunek2, tabela 3) i ciepło spalania (tabela 2 i 3). Wyniki analizy derywatograficznej wskazują na powiązanie właściwości energetycznych próchnicy z jej frakcjami rozdrobnienia (tabela 2, 3, rysunek 4). Nie stwierdzono natomiast korelacji między pH i rozdrobnienieniem próchnicy (rysunek 3, tabela 3). Analiza rozdrobnienia próchnicy charakteryzuje nie tylko właściwości morfologiczne ale jest również stosunkowo dobrą miarą jej przetworzenia.A relationship has been found between the disintegration degree of humus making up the organic horizon of the mor type and its properties related to the transformation process. As humus disintegration increases, there is an increase in mineral components content, an increase in humification degree, changcs in the course of DTA curves and an increase in combustion heat. The sieving method can be useful for morphological characterization of humus as well as for estimating its transformation degree

Changes in the chemical composition of water percolating through the soil profile in a moderately polluted catchment

Throughfall (TF), stemflow (SF), soil solution below the organic layer (SSorg) and at 50 cm depth (SS50), and output with stream water (SW) were measured and analyzed for four years in a moderately polluted forest catchment in southern poland. The input of water with stemflow was ca. 6 A of input with TP. However, due to higher concentrations of most ions in SF, the input of most elements with SF was from 8% to 9%. Sulphate (SO42-), chloride (Cl-) and magnesium (Mg2+) were the only ions steadily increasing in concentrations in water percolating through the soil profile. Nitrogen reached the forest floor mainly as ammonium (NH4+). In the soil organic layer the NH4+ concentration decreased, while concentrations of nitrate (NO3-) and hydrogen (H+) increased, probably due to nitrification. For NO3-, sodium (Na+) and calcium (Ca2+), the highest concentrations were found in SSorg and SW. This indicates both efficient cycling in the biotic pool of the ecosystem and intensive weathering processes in the mineral soil below the plant rooting zone. The latter was especially pronounced for Mg and Ca. Concentrations of zinc (Zn), lead (Pb) and cadmium (Cd) were the highest in SSorg and SS50. As this was accompanied by a low pH and constant input of H+, NH4+ and heavy metal ions to the catchment area, it may pose a serious threat to forest health

Evolutionary Position and Leaf Toughness Control Chemical Transformation of Litter, and Drought Reinforces This Control: Evidence from a Common Garden Experiment across 48 Species

International audiencePlant leaf litter is an important source of soil chemicals that are essential for the ecosystem and changes in leaf litter chemical traits during decomposition will determine the availability of multiple chemical elements recycling in the ecosystem. However, it is unclear whether the changes in litter chemical traits during decomposition and their similarities across species can be predicted, respectively, using other leaf traits or using the phylogenetic relatedness of the litter species. Here we examined the fragmentation levels, mass losses, and the changes of 10 litter chemical traits during 1-yr decomposition under different environmental conditions (within/above surrounding litter layer) for 48 temperate tree species and related them to an important leaf functional trait, i.e. leaf toughness. Leaf toughness could predict the changes well in terms of amounts, but poorly in terms of concentrations. Changes of 7 out of 10 litter chemical traits during decomposition showed a significant phylogenetic signal notably when litter was exposed above surrounding litter. These phylogenetic signals in element dynamics were stronger than those of initial elementary composition. Overall, relatively hard-to-measure ecosystem processes like element dynamics during decomposition could be partly predicted simply from phylogenies and leaf toughness measures. We suggest that the strong phylogenetic signals in chemical ecosystem functioning of species may reflect the concerted control by multiple moderately conserved traits, notably if interacting biota suffer microclimatic stress and spatial isolation from ambient litte