1. 26 28 23 Nitrogen (N) use efficiency of rice grown in Arkansas.
Total Rice Acres§
1,380,000
1,410,000
1,400,000
Total N Fertilizer Applied (lbs)§ A
197,340,000
204,450,000
288,400,000
Average N fertilizer Applied (lbs/ac)§
143
145
206
Total Rice Yield (lbs)§
7,590,000,000
8,615,100,000
9,660,000,000
Percent N in Rice Grain†
1.3
Total N Removed in Grain (lbs)§
98,670,000
111,996,300
125,580,000
N Removed from Soil (lbs)‡
47,361,600
53,758,224
60,278,400
N Removed from Fertilizer (lbs)§ B
51,308,400
58,238,076
65,301,600
Efficiency (%) [B/A] X 100 26 28 23 § †
‡ Calculated using a factor of 0.48; determined from multiple N fertility trials in Arkansas.
150 31

2. Increasing NUE in Rice Reduce Two Major Loss Mechanisms
Volatilization and Nitrification/Denitrification
Urease and nitrification inhibitors
Quickly applying flood water to achieve anaerobic conditions
Maintaining flood water to keep anaerobic conditions

3. Rice Root Density
Yoshida and Hasegawa (1982)
Because of the extensive root system of rice, the crop is able to accommodate for not being able to take up NO3 via mass flow