The global challenge of meeting increased food demand and protecting environmental quality will be won or lost in cropping systems that produce maize, rice, and wheat. Achieving synchrony between N supply and crop demand without excess or deficiency is the key to optimizing trade-offs amongst yield, profit, and environmental protection in both large-scale systems in developed countries and smal...

this study was conducted to determine the effect of variable nitrogen supply on yield parameters of two sugar beet varieties, as well as on biomass allocation to different parts of sugar beet plant at safi-abad agric. res. center during 2003-4 and 2004-5. five nitrogen rates (0, 60, 120, 180 and 240 kgha-1) and two monogerm sugar beet varieties (shirin and rasol) arranged as factorial in a rand...

BACKGROUND Despite the large stocks of organic nitrogen in soil, nitrogen availability limits plant growth in many terrestrial ecosystems because most plants take up only inorganic nitrogen, not organic nitrogen. Although some vascular plants can assimilate organic nitrogen directly, only recently has organic nitrogen been found to contribute significantly to the nutrient budget of any plant. C...

Density functional theory methods(DFT) and natural bond orbital (NBO) analysis were used to investigate the effects of isomerism and side chain mutation at a microscopic level on the stability, binding energy and NMR/NQR tensors of structural isomers, L- methionylasparagine (Met-Asn) and L- asparagylmethionine (Asn-Met) in the gas phase. The results represented that the isomerism and side chain...

The C(3) grass Poa trivialis and the C(4) grass Panicum maximum were grown in sand culture and received a complete nutrient solution with nitrogen supplied as 1.5 mol m(-3) NH(4)NO(3). (15)N tracer techniques were used to quantify the relative use of root uptake and mobilization in supplying nitrogen to growing leaves in intact plants which either continued to receive nitrogen or which received...

Traits that permit successful invasions have often seemed idiosyncratic, and the key biological traits identified vary widely among species. This fundamentally limits our ability to determine the invasion potential of a species. However, ultimately, successful invaders must have positive growth rates that longer term result in higher biomass accumulation than competing established species. In m...

the effect of levels of nitrogen on growth and nitrogen uptake patterns and grain protein quality of grain sorghum was investigated by two experiments which were conducted at pakdasht-tehran in 2003. in a completely randomized design with three replications, grain sorghum (sorghum bicolor (l.) moench) hybrid h-726 was grown under greenhouse conditions using water culture technique. the first ex...

in order to evaluate the efficiency of inoculation of chickpea seeds with mesorhizobium and application of nitrogen and zinc on yield and yield components of rainfed chickpea an experiment was carried out in research station of shirvan-chardavel, ilam. the experiment was conducted in randomized complete block design (rcbd) with six treatments including mesorhizobium inoculation, nitrogen (40 kg...

to evaluate the effect of various levels of nitrogen fertilizer on nitrogen use efficiency and grain yield of canola cultivars, a split plot experiment based on randomized complete block design was conducted in 2007. factors were: nitrogen fertilizer at four levels (zero, 50, 100 and 150 kg/ha) in the main plots and canola cultivars at three levels (‘clover’, ‘opera’ and ‘okape’) in the sub plo...