Fig. 6. Average grain yield and flow-weighted concentration of NO3 in tile drains for 1996 through 1999. Yield bars followed by same letter within a year are not significantly different (P = 0.05).
Fig. 6. Average grain yield and flow-weighted concentration of NO3 in tile drains for 1996 through 1999. Yield bars followed by same letter within a year are not significantly different (P = 0.05).