was applied to the tubing to evacuate the lysimeters weekly. Samples were sent to the Analytical Research Lab for analysis of nitrateN. Data from all projects are expressed in units of kg ha-1, which is
a measurement of the nitrate-N loading that occurred based on nitrate-N concentration and volume of leachate.
NITRATE-N LEACHING
FROM NEWLY PLANTED TURFGRASS
'Empire' zoysiagrass and 'Floratam' St. Augustinegrass were sodded and N treatments were applied the same day at rates of 0.5,
1.0, 1.5, or 2.0 lbs N 1,000 ft-2. Nitrogen was applied as soluble
FIGURE 2. Nitrate-N leaching losses from newly planted Floratam St.
Augustinegrass.
urea. Half of the plots received the same treatments 30 days later.
Nitrate-N leaching from both grasses over all years was considerably greater than from the established grass studies, regardless of N
rate (Figure 2). The percent of applied N that leached from St. Augustinegrass in 2006 was 73.4% of what was applied the same day
as planting in 2006. Leaching from the plots that received a second
treatment 30 days later was reduced to 56.4% of the applied N.
Similar results were seen in all years.
Newly planted turf, whether sodded, seeded, sprigged, or
plugged, should not be fertilized with N for at least 30 to 60 days
after planting, due to the potential for large nutrient losses before a
root and/or shoot system has been established. This is now a Best
Management Practices (BMP) recommendation.
NITRATE-N LEACHING
FROM ESTABLISHED TURFGRASS
Nitrogen was applied to Empire zoysiagrass and Floratam St.
Augustinegrass over a 3-year study. Annual N rates were 1, 4, 7, or
10 lbs N 1,000 ft-2 applied every 60 days throughout the growing
season. Nitrogen was applied as soluble urea. Leaching data are presented for 2006 and 2007 for each of the four Fertilizer Cycles (defined as the 60-day interval between each fertilizer application).
Fertilizer cycles are presented as spring (April-May), Early Summer
(June-July), Late Summer (Aug-Sept), and fall (Oct-Nov).
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