The contribution of ammonia-oxidizing bacteria and archaea (AOB and AOA, respectively) to the net oxidation of ammonia varies greatly between terrestrial environments. To better understand, predict and possibly manage terrestrial nitrogen turnover, we need to develop a conceptual understanding of ammonia oxidation as a function of environmental conditions including the ecophysiology of associat...

In the recent years radioecological studies are concentrated on the investigation of restoration possibilities of contaminated ecosystems. These studies are aimed to develop methods for decreasing the bioavailability of the radionuclides released to the environment. Radionuclides of long half-lives, such as 90Sr and 137Cs, are of special importance from the point of human health, since these nu...

Physiological investigations of nitrogen content and relation between nitrogen and chlorophyll content at some wheat cultivars were carried out at the outset of the flowering phase. Dependence of nitrogen content from mineral elements in the soil was established at the same time. Investigations were guided on unfertilized soil and four fertilization variants (N, NPK, NP and NK). The results ind...

Field experiments were carried out in Huantai County from 2006 to 2008 to evaluate the effects of different nitrogen (N) fertilization and irrigation management practices on water leakage and nitrate leaching in the dominant wheat–maize rotation system in the North China Plain (NCP). Two N fertilization (NF1, the traditional one; NF2, fertilization based on soil testing) and two irrigation (IR1...

The importance of the Northern Guam aquifer as a source of drinking water for the tropical Pacific island of Guam has stimulated public interest in the impact of forest clearing and conversion to agriculture on the region’s environment. The objectives of this study were to determine the effects of land clearing, tillage, and fertilization of tropical secondary forest on soil organic and organic...

Intensive use of N fertilizers in modern agriculture is motivated by the economic value of high grain yields and is generally perceived to sequester soil organic C by increasing the input of crop residues. This perception is at odds with a century of soil organic C data reported herein for the Morrow Plots, the world's oldest experimental site under continuous corn (Zea mays L.). After 40 to 50...

Nutrient rich conditions often promote plant invasions, yet additions of non-nitrogen (N) nutrients may provide a novel approach for conserving native symbiotic N-fixing plants in otherwise N-limited ecosystems. Lupinus oreganus is a threatened N-fixing plant endemic to prairies in western Oregon and southwest Washington (USA). We tested the effect of non-N fertilizers on the growth, reproducti...

this work investigates the effect of the application rate and type of sludge throughout the soilcarbon cycle in a semiarid mediterranean agro-ecosystem. we study the two-year evolution of the variouspools of soil organic and inorganic carbon and their influence on soil respiration. we applied three rates (40, 80 and 160 mg/ha) of two types of sludge –aerobically and anaerobically digested sewag...