71 

 the season at an annual rate of 49 kg/ha P (112 kg/ha P ? 0,-) and 186 kg/ 

 ha K (224 kg/ha K 0) . The source of P and K was an 0-10-20 grade 

 fertilizer mixture composed of concentrated superphosphate and muriate 

 of potash. Micronutrients were applied each spring at 34 kg/ha of 

 Fritted Trace Elements (F.T.E.) no. 503. 



The experimental design at both sites was a randomized block with 

 nine treatments and four replications. Plot size was 2.44 x 4.87 m 

 (.00119 ha). Two annual rates of N — 200 and 400 kg/ha — and four annual 

 rates of S — 0, 10, 20, and 40 kg/ha — were applied. Nitrogen and S were 

 applied as agricultural grade NH,N0„ and CaS0,-2H 0, respectively. The 

 N was applied after each harvest in four split applications during the 

 season. All of the S was applied in the spring before growth began 

 except for the ninth treatment. This treatment included four split 

 applications of S at an annual rate of 20 kg/ha and 400 kg/ha of N. 



Plots were harvested four times during the growing season: 

 (1) the second week in May, (2) the last week in June, (3) the first 

 week in August, and (4) the last week in September. A 1-m strip the 

 length of the plot (4.87 m) was harvested with a Gravely tractor with a 

 sicklebar mower. The forage was weighed, and a 300 to 500-g subsample 

 was removed for moisture determination and chemical analysis. This 

 sample was weighed, dried in a forced-air oven at 70 C for several 

 days, weighed again, and double-ground to pass a 1-mm sieve. Total N 

 and S were determined on the tissue by methods described in the next 

 section. 



Frit Industries, Inc., Ozark, Alabama. 



