Living roots and their rhizodeposits affect microbial activity and soil carbon (C) and nitrogen (N) mineralization. This so-called rhizosphere priming effect (RPE) has been increasingly recognized recently. However, the magnitude of the RPE and its driving mechanisms remain elusive. Here we investigated the RPE of two plant species (soybean and sunflower) grown in two soil types (a farm or a pr...

Irrigation with reclaimed wastewater (effluent) is one way to dispose this waste particularly in water scarce arid and semi-arid areas. Secondary effluent used for irrigation contains considerable amounts of N, both in inorganic and organic forms. Whereas attention was given to transformations of inorganic N originated from effluent, little is known regarding the fate of the organic N in efflue...

1 Nitrification is an important microbial process in humid tropical ecosystems because of its effects on potentials for nitrogen loss via nitrate leaching and denitrification and on the hydrogen ion cycle. Nitrification rates in humid tropical soils vary markedly among different forest types but in general appear to increase following disturbance. Proximal controls on nitrifiers include ammoniu...

Abstract In southern China, the eucalyptus plantation industry has been severely restricted by government policy over concerns on negative environmental impacts. its place, large-scale plantations of high-value tropical tree species such as nitrogen-fixing Dalbergia odorifera and hemiparasite Santalum album have widely cultivated including in mixed-species plantations. However, despite their po...

Newly synthesized amino acids are the principle compounds created after inorganic nitrogen (N) is rapidly immobilized into microbial tissues. However, little is known about the mineralization kinetics of these newly synthesized amino acids compared to the amino acids originally present in the soil, and how substrate availability controls their mineralization. With 15N isotope tracing, the newly...

Application of plant residues as soil amendment may represent a valuable recycling strategy that affects carbon (C) and nitrogen (N) cycling in soil–plant systems. The amount and rate of nutrient release from plant residues depend on their quality characteristics and biochemical composition. A laboratory incubation experiment was conducted for 120 days under controlled conditions (25 C and 58 %...

span of years also greatly affects C and N dynamics. Wood et al. (1990) measured greater potentially minerCycling of N through an agroecosystem can be managed more alizable C and N in surface soils of a wheat–corn–millet– effectively if effects of N management and cropping sequence on soil fallow (WCMF), 4-yr rotation than a WF, 2-yr rotation. N microbial processes are understood. Effects of cr...

An incubation experiment was conducted to study the effect of clay content and composition on organic nitrogen mineralization. The measured mineralization from alfalfa residues, enzyme activities, microbial biomass in mixtures sand, kaolinite, non-layered colloids (NLCs) with sand as a control. found that contents kaolinite NLCs increased, activity decreased, but increased. maximum decrease 88....

Voles are well-known crop pests, especially when peak populations are present, but their role in soil fertility and impacts on agricultural sustainability are not well understood. Five months after the abrupt disappearance of a peak in a gray-tailed vole (Microtus canicaudus) population, we examined burrow structure, determined concentrations of trace elements, carbon and nitrogen in the soil i...