introduction cultivated sunflower is one of the largest oilseed crops in the world. sunflower seed is the third largest source of vegetable oil worldwide, following soybean and canola. nitrogen is one of the most important elements for crops to achieve optimum yields and quality. phosphorus (p), next to nitrogen, is often the most limiting nutrient for crop and forage production. phosphorus ava...

this experiment was conducted in 2012 at the research field of alborz research station, research institute of forests and rangelands, karaj, iran, to study the effect of chemical and biological fertilizers on sage (salvia officinalis l.) and replacing biofertilizers instead of high doses of chemical fertilizers. the experiment was conducted in factorial in the form of a randomized complete bloc...

in order to study the effects of rate and application time of nitrogen on grain yield of rainfed wheat, water use efficiency of rain (wue), nitrogen agronomic efficiency (nae) and soil moisture depletion (smd), one experimental farm was carried out in kurdistan province during 2012-2014. tratments were five rates of nitrogen (n0, n30, n60, n90 and n120) kg.ha-1 as urea with three application ti...

[1] Biogeochemical studies show that the surface waters of the subtropical North Atlantic are highly phosphorus (P) stressed. Human activity may exacerbate phosphorus stress by enhancing atmospheric nitrogen (N) deposition and raising N/P ratios in deposition. However, the magnitude of this effect is unclear, in part, because atmospherically deposited phosphorus sources are not well known, part...

sensitivity analysis might be considered as one of inevitable steps in modelling since it would help to determine the behaviour of model, which was developed for further application. sensitivity analysis was not paid much attention in studies that have been conducted for modelling the relationship between stream water quality and land cover except machine learning techniques such as artificial ...

This experiment was conducted to determine the effects of nitrogen and phosphorus fertilizers on nutritive value of safflower forage and silage by in situ and in vitro methods. The safflower forage was harvested at flowering stage, chopped to 3-5 cm particles and then ensiled in the laboratory silos for 60 days. The experimental treatments included: 1. Unfertilized forage (control), 2. Phosphor...