Fig. 8. Relationships between the flux ratio of NO-N to N2O-N and water-filled pore space (WFPS) during the peak emission period (from 7–15 June 1998) (daily mean). The treatments were (a) poultry manure (PM), (b) swine manure (SM), and (c) urea. Solid line: regression (a) y = -0.0046x + 0.238, R2 = 0.453, p < 0.05; (c) y = -0.659x + 33.4, R2 = 0.441, p < 0.05.