Fig. 4. Effects of winter flooding (WF), nonwinter flooding (NF) and straw incorporation on soil microbial biomass N (top), C (center) and C:N ratio (bottom) in the 0- to 15-cm depth, 1997 to 1999. All treatments were flooded during the cropping season while only the winter flooded treatments were flooded during the winter fallow period. Least-squares means, standard errors (N = 12)