the effect of nitrogen (n) levels on n uptake by high weed densities at early growth stages of corn (zea mays l., cv. double cross 370) was investigated for two years (2008-2009) at the agricultural research station of shiraz university. the experiment was arranged in a split-plot arrangement in the randomized complete blocks design with three replications. two levels of weed control (weedy and...

this research was conducted to study the effects of water deficiency stress, nitrogen application rates, and plant population on water use efficiency and nitrogen of oily sunflower in 2007-2008 agriculture and research center of west-azerbaijan. the study was consisted split-split-plot experiments using randomized complete block design with 3 replications. the factor main was consisted irrigati...

An experiment was conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during boro season of 2014 to evaluate the effect of deep placement of nitrogen (N) fertilizers on N use efficiency and yield of BRRI dhan29 under flooded condition. The soil was silt loam in texture having pH 6.27, organic matter content 1.95%, total N 0.136%, available P 3.16 ppm...

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...

This experiment evaluated forage production, sward structure, stocking rate, weight gain per area and nutritive value of forage as grazed by beef heifers on Alexandergrass (Urochloa plantaginea (Link) Hitch) pasture fertilized with nitrogen (N): 0; 100; 200 or 300 kg of N/ha. The experiment was a completely randomized design following a repeated measurement arrangement. The experimental animals...

Field experiments were performed to identify an effective fertilizing scheme for direct-seeding rice (DSR) fields in the Taihu Lake Basin in east China. Based on local traditions, 3 typical fertilizing schemes (FS-1, FS-2, and FS3) were evaluated, in consideration of ensuring a certain rice yield and relatively low nitrogen (N) loss. The base, seedling, tillering, jointing, and panicle fertiliz...

A randomized block experiment conducted on Sultanpur silt loam evaluated the N effects on growth and nitrate accumulation of okra (Hibiscus esculents L. cv. Sabz pari) and carrot (Daucus carota L. cv. T29). Treatments consisted of a control, 100, 150 and 200 kg N ha. Significantly higher yields of carrot and okra were recorded at 150 kg N ha. Nitrate concentration in both increased (> 35 to 200...

Excessive use of animal manure on agricultural lands can impact the quality of surface and groundwater resources. A three–year study (1998–2000) was conducted on nine 0.4–ha plots and on six 2.1–m 2 lysimeters to investigate the effect of two nitrogen (N) application rates from laying hen manure and one N application rate from urea ammonium nitrate (UAN) fertilizer on surface and groundwater qu...

An accurate and management sensitive simulation model for tile-drained Midwestern soils is needed to optimize the use of agricultural management practices (e.g., winter cover crops) to reduce nitrate leaching without adversely affecting corn yield. Our objectives were to enhance the Agricultural Production Systems Simulator (APSIM) for tile drainage, test the modified model for several manageme...

Long-term field experiments are needed to fully realize positive and negative impacts of conservation tillage and poultry litter application. A study was initiated on a Decatur silt loam soil at the Tennessee Valley Research and Extension Center, Belle Mina, AL, USA in 1996 to evaluate cotton (Gossypium hirsutum L.) performance with long-term poultry litter (PL) application under different till...