Fig. 1. Mineral N in soil (0 to 15 cm) during pre-rice fallow and rice growing season of 1995 as affected by incorporating wheat residue and fertilizer N (a) without green manure and (b) with green manure. Time of wheat residue (WR) incorporation. Time of green manure (GM) incorporation and flooding. Time of fertilizer N (FN) application. All treatments had no rice residue and 120 kg FN ha^-1 in the wheat seasons. Bars represent SE, shown in only one direction for clarity