INTRODUCTION


 High rates of nitrogen (N) applied to acid soils increase the requirement
 for lime application to maintain soil pH at levels favorable for production of
 most crops. Coastal bermudagrass responded positively to N-rates up to 400
 lb/acre with no lime added for a period of three years (Adams et al., 1967).
 However, yields declined each year without lime at N-rates of 800 and 1600
 lb/acre. A positive response to N-rates up to 1600 lb/acre was observed with
 adequate lime applied. Nitrogen recovery dropped rapidly when N fertilizer
 rates increased from 600 to 1200 lb of N/acre in Alabama (Doss et al., 1966).
 Anhydrous ammonia produced lower bermudagrass yield than ammonium nitrate and
 urea at N-rates greater than 100 lb/acre (Hill and Tucker, 1968). Near maxi-
 mum coastal bermudagrass yield occurred with 800 lb of N/acre in North Georgia
 (Wilkinson and Langdale, 1974).

 A reduction in sulfur oxides entering the atmosphere, as well as the
 increasing use of sulfur-free fertilizers have the potential to cause sulfur
 (S) deficiency problems under the soil and climatic conditions of the South-
 eastern United States. Ammonium sulfate contains both N (21%) and S(24%), but
 research on its use as a source of sulfur for coastal bermudagrass is limited
 (Burton and Jackson, 1962, and Matocha, 1971). Ammonium sulfate produces
 twice as much acidity per unit of N as ammonium nitrate.

 Objectives of this report were to determine: (1) coastal bermudagrass
 response to N-rates, (2) minimum and maximum N-rates for coastal bermudagrass,
 and (3) expected soil pH reduction due to application of ammonium nitrate and
 ammonium sulfate.

 METHODS
 Coastal bermudagrass sprigs were planted in July of 1984 at the North
 Florida Research and Education Center, Quincy on a Dothan loamy sand (Plinthic
 Kandiudult). A full season harvest was not made until 1986 when the stand was
 well established.

 Annual applications of 500 lb/acre of triple superphosphate (46%) and 700
lb/acre of muriate of potash were made in early March of each year following
establishment of the coastal bermudagrass sod. Zinc sulfate (36% Zn) and
solubor (20% B) were applied at the beginning of the study at 28 and 25
lb/acre, respectively.

 Two tons/acre of dolomite were incorporated into the soil before planting
the bermudagrass sprigs in 1984. Dolomite was applied over the top of
bermudagrass in the fall of 1987 at the rate of 1-ton/acre.

 Nitrogen rates were 0, 200, 400, 600, and 800 lb/acre, with each rate
supplied separately by ammonium nitrate and ammonium sulfate for a total of
nine treatments. One-half of the N for each treatment was applied in the
spring when plant growth resumed and one-half was applied following the second
harvest. Soil samples (10 cores per plot, 1-inch x 6-inches, composite) were
collected from each plot in June, 1986 and December 1988 for soil-pH
determination with a glass electrode pH meter.