we proposed to use artificial channels in laboratory assays to expose periphyton to substancesreleased in rural environments in order to test the following hypotheses 1) a high concentration of humicsubstances decreases the biofilm biomass and alters its metabolism; 2) periphyton biomass and metabolism increase in response to nutrient addition in spite of the previous high nutrient concentratio...

An experiment was carried out to evaluate the effect of various concentrations of Mg (0, 1, 2, 3 and 4 mM) in the nutrient solution and shading (0 and 50%) on growth, yield, fruit quality and physiological properties in hydroponically grown cucumber (Cucumis sativus L. cv. Nagen 792). With increased Mg concentration in both shaded and unshaded plants, the total plant leaf area and dry weight of...

Mycorrhizal associations are generally favourable for vascular plants in nutrient-poor conditions. Still, non-mycorrhizal plants are common in high arctic and alpine areas, which are often poor in nitrogen and phosphorus. The relative proportion of mycorrhizal plants has been found to decrease along with increasing altitude, suggesting that the advantage of the mycorrhizal symbiosis may change ...

Wood vinegar is a substance, derived from cooling black carbon fire, which could be used instead of chemical materials in the agriculture industry as an organic compound. In order to study the effectiveness of pine wood vinegar on physiological and photosynthesis traits of cucumber, two experiments were conducted based on a completely randomized design with six treatments including 0, 1250, 200...

New irrigation methods under different nutritional element supplies for maize production was designed and tested for evaluate quantitative and qualitative parameters by split-plot arrangement according complete randomized block design with three replications. Different Irrigation regimes was belonged to main plots (Conventional furrow irrigation: CFI or A1, Alternate furrow irrigation: AFI or A...

A simple food chain which consists of nutrient, prey and predator in which nutrient is growth limiting at low concentrations but growth inhibiting at high concentrations is investigated in this study. It is assumed that the nutrient concentration is separated into internal and external nutrient concentration and only the internal nutrient level is capable of catalyzing cell growth. It is shown ...

Changes in land use may lead to increased soil nutrient levels in many ecosystems (e.g. due to intensification of agricultural fertilizer use). Plant species differ widely in their response to differences in soil nutrients, and for savannas it is uncertain how this nutrient enrichment will affect plant community dynamics. We set up a large controlled short-term experiment in a semi-arid savanna...