in order to study the effect of organic fertilizers application on increasing nitrogen efficiency and also quantitative and qualitative characteristics of sugar beet, a series of experiments were performed for two years (2008 and 2009) using three amino acid containing organic fertilizers at motahari research station of sugar beet seed institute (sbsi), karaj, iran. four rates of organic fertil...

crop rotation affect on crop nitrogen uptake and nitrogen use efficiency (nue). crop rotations with high nue decrease energy use and increase level of sustainability in agro ecosystems. the objectives of this research were to determine the suitable double cropping system for enhancing nue and evaluate the effects of crop rotation, n fertilizer rate and return of crop residue on nue. this study ...

In this study, nitrogen fertilizer was applied to corn (Zea mays L.) at conventional (excessive) and recommended levels, and the growth response was assessed by measuring plant height and stem perimeter. Corn plant maximum height was observed in recommended rates of N fertilizer treatment, and the height without N fertilizer was the same as that receiving excess N fertilizer. Stem perimeter was...

this study was conducted under cold temperate climate condition in khorasan during 2006-2008 growing seasons to determine the suitable wheat-based double cropping systems for increase nitrogen agronomic efficiency. a randomized complete block design in split-split plot arrangement with three replicates was used. main plots were crop rotation with five different rotations including wheat:wheat, ...

estimation of optimum fertilizer rates is needed because of growing economic and environmental concerns. optimum fertilizer rates can be determined by fitting statistical models to yield data collected from n fertilizer experiments. the main goal of this research was to compare and evaluate quadratic, square root, mitscherlich, rectangular hyperbola, linear plus plateau and quadratic plus plate...

in order to evaluate different sources and rates of nitrogen on dry matter yield, concentration and uptake of primary macronutrients (nitrogen, phosphorous and potassium) in forage sorghum (hybrid of speedfeed), three levels of nitrogen (80, 160 and 240 kg n ha-1) from three n sources (urea fertilizer, cattle manure and equal combination of urea fertilizer + cattle manure) and the control (no f...