Beginning in October 1998, half of the microcosms from each mulch treatment (selected
randomly) were fertilized with 18:5:4 NPK applied at a rate of 150 kg N ha-1 yr-1, and the other
half were left untreated. Half of the annual amount of fertilizer was applied in early May, and
the other half in early October. Nitrogen was applied in the form of methylene urea (56%),
water-soluble urea (27%), and ammonium nitrate (17%). Our fertilization treatment represents a
low rate for ornamental landscapes based on extension recommendations, which range from
147–294 kg ha-1 yr-1 of actual N (3–6 lbs 1000 ft-2 yr-1), with N, P and K applied in ratios ranging
from 3:1:1 to 3:1:2 (Smith, 1989).