Fig. 7. Relationships between annual mean NO3–N loads in the Iowa River at Wapello and annual means for (A) soil NO3–N concentrations in late spring and (B) cornstalk NO3–N concentrations at the end of the growing season.
Fig. 7. Relationships between annual mean NO3–N loads in the Iowa River at Wapello and annual means for (A) soil NO3–N concentrations in late spring and (B) cornstalk NO3–N concentrations at the end of the growing season.