FIG. 1
FIG. 1

Relationship between rice percentage of relative grain yield and N rate for sites that produce (A) positive response and (B) negative response due to the increasing addition of N fertilizer. Data adapted from ROBERTS et al. 2008.

 


FIG. 2
FIG. 2

Correlation of percentage of relative grain yield (RGY) of the rice receiving no N versus alkaline hydrolyzable-N (AH-N) as determined by the Illinois Soil Nitrogen Test (ISNT) for the four cumulative depths (A) 0 to 15 cm, (B) 0 to 30 cm (C) 0 to 45 cm, and (D) 0 to 60 cm, respectively. All correlations were significant at the 0.001 level of probability.

 


FIG. 3
FIG. 3

Correlation of percentage of relative grain yield (RGY) of the rice receiving no N versus alkaline hydrolyzable-N (AH-N) as determined by Direct Steam Distillation (DSD) for the four cumulative depths (A) 0 to 15 cm, (B) 0 to 30 cm, (C) 0 to 45 cm, and (D) 0 to 60 cm, respectively. All correlations were significant at the 0.001 level of probability.

 


FIG. 4
FIG. 4

Calibration curve for the N rate to achieve 95% relative grain yield (RGY) utilizing alkaline hydrolyzable-N (AH-N) as determined by the Illinois Soil Nitrogen Test (ISNT) for the four cumulative depths (A) 0 to 15 cm, (B) 0 to 30 cm (C) 0 to 45 cm, and (D) 0 to 60 cm, respectively. All correlations were significant at the 0.001 level of probability.

 


FIG. 5
FIG. 5

Calibration curve for the N rate to achieve 95% relative grain yield (RGY) utilizing alkaline hydrolyzable-N (AH-N) as determined by direct steam distillation (DSD) for the four cumulative depths (A) 0 to 15 cm, (B) 0 to 30 cm, (C) 0 to 45 cm, and (D) 0 to 60 cm, respectively. All correlations were significant at the 0.001 level of probability.