| Broccoli requires sufficient levels of nitrogen to maintain high yields and quality, however the loss of nitrogen from agricultural systems can have a deleterious effect on the environment and public health. Field trials were conducted in 2001 and 2002 to determine the effect of soil applied nitrogen fertilizer on the growth, yield, quality and nitrogen dynamics of broccoli. Seven rates of nitrogen (0, 50, 100, 150, 200, 300, 400 kg N ha -1) as ammonium nitrate were broadcast and incorporated before planting of two broccoli cultivars. Crop growth, marketable yield, and visual quality increased at high nitrogen rates. Rates required to optimize yield were high (296 to 335 kg N ha-1) and may pose an unacceptable environmental risk. In addition, 96 to 330 kg N ha-1 remained in the soil and crop residue at harvest. Improved nitrogen application techniques and strategies to deal with high nitrogen crop residue are needed to balance yield, quality, and environmental protection. |
