Fig. 3 Mean biomass of weeds from 1994 to 1998 in the plots with the different treatments. Different letters mean significant differences between treatments within years (a,ab,b = 1994; A,B,C = 1995; x,y,z = 1996; a,b,c,d = 1998) p < 0.05
Fig. 3 Mean biomass of weeds from 1994 to 1998 in the plots with the different treatments. Different letters mean significant differences between treatments within years (a,ab,b = 1994; A,B,C = 1995; x,y,z = 1996; a,b,c,d = 1998) p < 0.05