in order to investigation the effect of different fertilization treatments on nutrient and essential oil contents in dragonhead drug (dracocephalum moldavica l.), an experiment was conducted in the station of agricultural research in urmia on 2008. treatments (nitroxin, barvar phosphate biofertilizer, biosulfur, nitroxin+ barvar phosphate biofertilizer, barvar phosphate biofertilizer + biosulfu...

A hypothesis has been presented that nitrogen retention in lakes has become less efficient at the same time as phosphorus concentrations have decreased due to high phosphorus reduction in wastewater treatment. This might have led to higher loading of nitrogen into the Baltic Sea where nitrogen is considered to be the minimum nutrient. The hypothesis was tested using the mass balance modelling a...

abstract this study was conducted under cold climate condition in khorasan during 2006-2008 growing seasons to evaluation of soil fertility in wheat-based double cropping systems under different rate of nitrogen and return of crop residues. a randomized complete block design with split-split plot arrangement and three replicates was used. main plots were five crop rotations namely: wheat-wheat,...

this study investigated the impact of internal nitrogen and phosphorus loading on water qualityof lake chaohu, china. results showed that the overall mean concentration of tn and tp in lake water was1.09±0.84 and 0.15±0.84 (sd) mg/l, respectively, indicating lake chaohu was highly eutrophic during thestudy period. mean benthic flux of nh4 +, no3 -, and po4 3- were 3.56±1.52 mg n/m2/d, -0.14±0.4...

this study investigated the impact of internal nitrogen and phosphorus loading on water qualityof lake chaohu, china. results showed that the overall mean concentration of tn and tp in lake water was1.09±0.84 and 0.15±0.84 (sd) mg/l, respectively, indicating lake chaohu was highly eutrophic during thestudy period. mean benthic flux of nh4 +, no3 -, and po4 3- were 3.56±1.52 mg n/m2/d, -0.14±0.4...

This study was conducted in order to investigate the effect of drought stress and Azomite fertilizer on some physiological traits of two tomato (Lycopersicon esculentum M.) cultivars (izmir and Izabella). A randomized complete design with factorial arrangement with three replications was used. Treatments consisted of three levels of irrigation including FC (control), FC (mild drought stress), a...

The seasonal nutrient mass balance of the dominant seagrass of the Mediterranean, Posidonia oceanica (L.) Delde, was evaluated in NE Spain in order to test the hypothesis that the effect of seasonal nutrient imbalance can be reduced by the reutllization of internal nutrient pools. To this end we investigated the seasonal and age-dependent variability of nitrogen and phosphorus concentration of ...

Removal of nitrogen and phosphorus is known to be somewhat problematic in vertical subsurface flow (VSSF)constructed wetlands. In this pilot-scale study, two planted (Typha latifolia L. [cattail]) VSSF-constructed wetlands A (with polypropylene pellets) and B (without polypropylene pellets) and one unplanted control C (without polypropylene pellets) were designed to test the contribution of pol...

The effects of phosphorus and nitrogen limitation on polyhydroxyalkanoate (PHA) production and accumulation by activated sludge biomass with acetate as a carbon source were investigated. Pre-selected influent carbon-phosphorus (C:P, W/W) of 100, 160, 250, 500 and 750, and carbon-nitrogen (C:N, W/W) of 20, 60, 100, 125 and 180 were applied in the phosphorus limitation experiments and the nitroge...

kochia scoparia is a salt resistant plant that can be used in producing forage in the areas with salt water and soil resources. one of the problems which produce the forage plants in these areas decreases the function and quality of the forage in irrigation condition with salt water. therefore, using the chemical fertilizers can be considered as a useful solution. this study was conducted to ev...