Hi R usres, I would like to specify y label units in xyplot. I tried the yaxp, but it does not work. Following are my codes; trellis.device(col=F) xyplot(GY~N|S,data = Ahmed, layout=c(5,1,1), xlab=expression(paste("N rate (kg ", ha^-1,")")), ylab=expression(paste("Biomass yield (Mg ",ha^-1,")")), ylim=c(12,20), #xlim=c(-50,700), strip = function(...) strip.default(...,style = 1), col=0, par.strip.text = list(cex = 0.7), scales = list(alternating=F, cex=0.7,yaxp=c(12,20,8)),aspect = 2, panel = function(x,y,subscripts,groups,...) { #panel.grid(-1,-1) m1 <- lm(y ~ x) x.seq <- data.frame(x=seq(min(x)*0.95,max(x)*1.05,max(x)/10)) pred <- predict(m1, x.seq, se.fit=T) grid.polygon(c(x.seq$x,rev(x.seq$x)), c(pred$fit + 2*pred$se.fit, rev(pred$fit - 2*pred$se.fit) ), gp=gpar(col=0, fill="light grey", alpha = 1), default.units = "native") llines(x.seq$x, pred$fit, lty = 1) panel.xyplot(x,y) print(round(summary(m1)$coef[ 2,c(1,4) ],3) ) #ltext(0,0.5,paste("Slope = ",round(summary(m1)$coef[2],3),sep=""), # cex=0.65, adj=0) #ltext(0,0.4,paste("P(slope) ",round(summary(m1)$coef[2,4],3),sep=""), # cex=0.65, adj=0) print(summary(m1)) } ) Any ideas Thank you Ahmed M. Attia Research Assistant Dept. of Soil&Crop Sciences Texas A&M University ahmed.attia at ag.tamu.edu Cell phone: 001-979-248-5215 FAX: 001-308-455-4024