production of onion all thruough the year particularly in semi tropical regions has been considered as an alternative to fulfil the local markets needs. in order to determine the best amount and method of urea fertilizer application so that to have higher yeild and lower amount of nitrate content the effects of seven levels of urea fertilizer including 0, 90, 180, 270, 360, 450 and 540 kg of ni...

rice (oryza sativa l.) is one of the iran's most strategic crops with water shortage as the most important abiotic stress limiting its yield. in the present research the effects of: variety, water regime, nitrogen (n) and phosphorus (p) levels on n, p and k uptake were studied under greenhouse conditions. the experiment design was a factorial one based upon a randomized complete blocks of ...

abstractbackground and objectives: in most saline and non-saline soils, nitrogen is the most restrictive nutrient for plant growth. in saline soils, interactive effects of salinity and soil fertility is very important from optimum production. nutrient imbalance is one of the problems with saline soils. in these circumstances, the fertilizer application may to increase osmotic effect of salt, th...

in order to evaluate the effect of nitrogen absorption and use efficiency in relay intercropping for winter wheat and maize, a field experiment was conducted during 2008-2009 at the agricultural research station of ferdowsi university of mashhad, iran. a randomized block design with three replications was used. treatments included four combinations of relay intercropping of wheat and maize (thr...

to estimate the optimum and effective amount of nitrogen fertilizer for quantity and quality improvement of three new durum wheat lines, this research was conducted in gachsaran dry-land agricultural research station for a duration of 4 years (2003-2007). the study was performed as a factorial expriment, using a randomized complete block design with 4 replications. two factors of: 4 nitrogen ra...

n order to investigate the effect of nitrogen fertilizer rates and top dressed on nitrogen remobilization in different rice cultivars, a field experiment was conducted in the rice research institute of iran (amol) during 2006. a split split experiment in the basis of randomized complete block design with 3 replications and 3 factors were used in which fertilizer rates in 3 levels (including 46,...

in the present study, the root vigor and kinetic characteristics of nitrogen absorption in potato cultivars was investigated through sand cultivation and pot tests with nutrient solution. four cultivars of potatoes, namely, feiwuruita, yunshu301, liangshu97, and chuanyu56 were grown in nutrient solution matrix cultures. the result showed that: (1) nitrogen uptake rates differed significantly am...

in order to evaluate plant density and different nitrogen levels on protein percent, yield and nitrate accumulation in potato tuber cv. agria, a factorial experiment based on randomized complete block design with three replications was conducted in ardabil in 2006. factors included nitrogen levels: 0, 80, 160 and 200 kg ha-1 net nitrogen and plant densities: 5.5, 7.5 and 11 plant m-2. results s...