我正在用图表绘制涉及不同肥料用量的实验数据（ggplot2）。我想指出在一系列观察日期（处理后的几天，或DAT）中的植物响应（数据中的营养指数或VI_Values）：9、15、21、27和35 DAT。当我绘制点的图形时，我的DAT（x轴）不按我想要的顺序排列，而我的y轴值不按顺序排列。我该如何解决这两个问题，以及如何重组y轴以增加偶数间隔？最好只在y轴上显示整数（或至少在整数后保留几位小数）。

运行此代码...

ggplot(data=dataset,aes(x=DAT,y=SR,group = Rate,colour = as.factor(Rate)))+
  geom_line()+
  geom_point()

...产生以下图形：

我需要按如下顺序订购x轴：9、15、21、27、35 DAT，我当然想清理该y轴。

这是数据集：

dataset <- data.frame(Cultivar = c("pio","pio","pio"),Rate = c(0,1,4,8,8),DAT = c(9,9,15,21,27,35,35),SR = c(5.443664,4.91077766666667,3.615712,2.81359,10.4675316666667,9.65146,7.646191,7.138025,8.24739066666667,7.85872166666667,6.14369533333333,5.83806466666667,13.3828463333333,12.3525363333333,11.0249503333333,10.5858046666667,13.8856,12.7933703333333,10.966898,11.194905),Error = c(0.138439743861123,0.445183750289448,0.716154295933728,0.209298947911833,0.485569061785356,0.870274032427143,0.92619068130992,0.896274542793855,0.225475438285661,0.863429277269874,0.522656438625583,0.827932691360905,0.741721042845025,1.2532188075592,1.01358403281381,1.16022067736693,0.262671210179824,1.02721331514967,0.626616072499209,0.669908769))

dput输出：

structure(list(Cultivar = structure(c(1L,1L,1L),.Label = "pio",class = "factor"),11.194905
    ),0.669908769)),class = "data.frame",row.names = c(NA,-20L))