Mining of nutrients from soil is a major problem causing soil degradation and threatening long-term food production in developing countries. In present research, an attempt was made for carrying out nutrient budgeting, which includes the calculation of nutrient balance at micro (plot / field) and meso (farm) level and evaluation of trends in nutrient mining / enrichment. A nutrient budget is an...

Wood contains the majority of the nutrients in tropical trees, yet controls over wood nutrient concentrations and their function are poorly understood. We measured wood nutrient concentrations in 106 tree species in 10 forest plots spanning a regional fertility gradient in Panama. For a subset of species, we quantified foliar nutrients and wood density to test whether wood nutrients scale with ...

the purpose of this study was to determine the effect of two levels of four commercial multi-enzymes on the apparent metabolizable energy corrected for nitrogen (amen) and digestibility of crude fat, crude protein, dry matter, and organic matter in broiler chickens through total excreta collection method. one hundred thirty male broiler chicks were assigned to 45 metabolic cages involving 9 tre...

The calculation of whole-farm nutrient balance is an effective and simple method for estimating the potential nutrient loading from dairy farming into the environment. In Finland, however, the published results based on larger number of farms are still lacking. In this study whole-farm nitrogen (N) and phosphorus (P) balances on Finnish dairy farms were studied based on short-cut data for the y...

Phenotypic plasticity in response to environmental variation occurs at all levels of organization and across temporal scales within plants. However, the magnitude and functional significance of plasticity is largely unexplored in perennial species. We measured the plasticity of leaf- and shoot-level physiological, morphological and developmental traits in nursery-grown Populus deltoides Bartr. ...

interrupting the processes which control ecosystem resources has dramatic impacts on the rangeland conditions. to protect ecosystems and landscape, it needs to understand the ecosystem processes which regulate the ecosystem resources. as main components of ecosystems, patches and inter-patches play important roles in energy and materials cascade. ecologically, functional parameters such as stab...

the nutrient elements uptake in many of soils, is a problem because of high ph and plenty of calcium ions in them. some of these elements are phosphorus and microelements. it is possible to increase absorption of these nutrient elements by addition of sulfur in soil and biological oxidation. the rate of this reaction is very slow and thiobacillus bacteria are the most important oxidators of sul...

Fire is a critical regulator of biogeochemical cycles in approximately 40% of the earth's land surface. However, little is known about nutrient release from combustion residues (ash and char) from herbaceous or grassland fires of varying intensity. Much of our knowledge in this area is derived from muffle furnace temperature gradient experiments. Therefore, we used two approaches (muffle and fl...

Ratio-dependent and prey-dependent models of trophic interactions make very different predictions about the steady-state (equilibrial) properties of ecosystems, such as the response of equilibrium abundance and biomass of organisms in each trophic level to increased primary productivity or nutrient input. Prey-dependent heory predicts alternating positive, negative, and zero responses of trophi...