in this research for study the effects of nitrogen fertilizer on yield and yield components of current rice cultivars was an experiment as factorial in rcbd with three replications where conducted during 2009 year in two locations (rice research institute, rasht, and rudsar, east of guilan). factors were cultivars (khazar, ali kazemi and hashemi), and nitrogen fertilizer levels (0, 30, 60, and ...

With uncertainty in future irrigation water availability and regulations on nutrient application amounts, experimentally determined effects of “controllable” management strategies such as nitrogen (N), water, and their combination on crop water productivity (CWP, also known as crop water use efficiency) and actual evapotranspiration (ETa) are essential. The effects of various N application rate...

A field experiment was carried out to assess biomass and nitrogen status inMediterranean pastures by means of hyperspectral high resolution field radiometric data. Spectral and agronomic measurements were collected at three different pasture growth stages and in grazed–ungrazed plots distributed over an area of 14 ha. Reflectance-based vegetation indices such as simple ratio indices (SR[i,j]) a...

Unsaturated zone N fate and transport were evaluated at four sites to identify the predominant pathways of N cycling: an almond [Prunus dulcis (Mill.) D.A. Webb] orchard and cornfield (Zea mays L.) in the lower Merced River study basin, California; and corn-soybean [Glycine max (L.) Merr.] rotations in study basins at Maple Creek, Nebraska, and at Morgan Creek, Maryland. We used inverse modelin...

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...

Nitrogen (N) in plants is generally diagnosed by a soil test and plant tissue analysis.However, such analyses are costly in terms of time and money and are not easily accessible byresearchers and extension workers, let alone farmers. Alternative cost-effective methods arerequired for rapid analysis of the N status of crops and to guide N management in wheat. Theobjective of this study was to as...

Although cool-season grasses increase DM yield at high N rates, N recovery (kg plant N kg 1 N applied) Nitrogen removal by cool-season grasses may aid in capturing exgenerally declines as N rate increases. Ramage et al. cess N from animal confinement operations or phytoremediation. (1958) reported fertilizer N recovery of 0.59 and 0.59 kg Limited information exists on the N dynamics of these gr...