background and objectives: production and use of fertilizers in common agriculture have been many environmental problems. while the application of organic fertilizers instead of chemical fertilizers have a important role in soil fertility, increase quality of production and safety of agricultural ecosystems. pumkin, is an important annual herbaceous plant belongs to the cucurbitaceae family due...

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...

A field experiment was conducted to study the effects of N fertilization on uptake,accumulation/remobilization, use efficiency and yield of sunflower grown in alluvial plains ofnorthwestern India comprising four hybrids (PSH 996, PAC 3789, PSH 569 and SH 3322)and five N levels (Control, 40, 80, 100 and 120 kg N ha-1) in split-plot design with threereplications. Increased N fertilizer rates sign...

water and nutrient availability are two major constraints to forage maize production in arid and semi-arid areas; however, the effect of different n levels from organic and inorganic sources on nutrient (i.e., n and p) efficiency under drought stress conditions is not well known for maize faming. thus, a field study was conducted with the objective of determining the effect of n fertilization a...

field experiments were conducted at the rice research institute (mazandaran province) using randomized complete block designs in two fields of different levels of organic carbon (low and medium) during two cropping years. the treatments were repeated in three replicates and while seven nitrogen levels (urea-n input) 0, 23, 46, 69, 92, 115 and 138 kg n per ha employed. results indicated that opt...

A series of experiments was carried out at Students Farm, Sindh Agriculture University, Tandojam to evaluate the effect of NPK, micronutrients and N-placement on the growth and yield of sunflower during 2005-2006. The sunflower cv. HO-1 was studied under 7 different NPK levels and placement methods (0-0-0 NPK kg ha, 6030-30 NPK kg ha (N as broadcast), 60-30-30 NPK kg ha (N as fertigation), 90-4...

to study the effect of type and different nitrogen fertilizers on controlling egyptian broomrape, field and greenhouse studies based on randomized complete block with three replications, were conducted at ferdowsi university of mashhad. greenhouse study treatments were consisted of ammonium nitrate, ammonium sulfate and urea each of which applied at four rates (75, 150, 300 and 350 kg/ha). fiel...

We reconstructed the historical trends in atmospheric deposition of nitrogen to Cape Cod, Massachusetts, from 1910 to 1995 by compiling data from literature sources, and adjusting the data for geographical and methodological di!erences. The reconstructed data suggest that NO 3 -N wet deposition to this region increased from a low of 0.9 kg N ha~1 yr~1 in 1925 to a high of approximately 4 kg N h...

Low soil fertility and high weed infestation are the main culprits for the declining maize production inWestern Kenya. Technology packages to address these constraints exist, but their effectiveness is likely to be influenced by variability in soil types and farm management practices in the region. Trials were conducted during the 2008/2009 cropping seasons to investigate the nutrient use e...