par＆lt; -mfrow时的宽度列

Question

我有两个条形图，我想要图1和图2中两列的宽度相等。如何控制列宽，在我的代码中“ylap”不是图形参数

op <- par(mfrow=c(1,2))
Nito1 <-matrix(c(2029,1197,1562,763,1464,2090,1125,1635,
                  802,1420,354,298,281,248,254), nrow = 3, byrow = T)
colnames(Nito1)<-c("Nt"," Nt lọc","TKN","TKN lọc","Amoni")
DT <- barplot(Nito1,main="Đồ Thị Nitơ", ylap="mg/l",width=1, beside = T)
Nito2<-matrix(c(1.36,1.75,1.41,1.97,18.30,6.20),nrow = 3, byrow = T)
colnames(Nito2)<-c("Nitrat","Nitrit")
DT <- barplot(Nito2,main="Đồ Thị Nitơ",width=1, beside = T)

链接图片：