Fig. 5. Percent soil microbial immobilized ¹⁵N fertilizer recovery over a two year period (1997–1999) in the 0- to 15-cm soil depth when straw was incorporated or burned and the fields were winter-flooded (WF) or nonwinter flooded (NF). Two kg ¹⁵N ha^-1 was added prior to planting in May, 1997. 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).