Reordering of grouped bars - r

Question

Below is the desired order: 10% runoff, 20% runoff, NOEC, LC50. Thank you in anticipation.
My code:
ggplot(pest_ana, aes(x = Pesticides, y = `Concentration (ug/L)`, fill= Concentrations)) +
geom_bar(stat = 'identity', position='dodge') + scale_fill_discrete (breaks = c("10% runoff","20% runoff","NOEC", "LC50"))+ scale_x_discrete(guide = guide_axis(n.dodge=2)) + scale_y_continuous(trans = log10_trans(),
breaks = trans_breaks("log10", function(x) 10^x),
labels = trans_format("log10", math_format(10^.x)))
Pesticides Concentrations Concentration (ug/L) Individual
Cypermethrin NOEC 4.8 1
Deltamethrin NOEC 3.37 2
Actara NOEC 20000 3
Carbofuran NOEC 40.6 4
Methomyl NOEC 260 5
Endosulfan NOEC 10.2 6
Fenvalerate NOEC 6.02 7
Glyphosate NOEC 5000 8
Mancozeb NOEC 301 9
Cypermethrin LC50 0.03 1
Deltamethrin LC50 0.032 2
Actara LC50 322000 3
Carbofuran LC50 500 4
Methomyl LC50 4015 5
Endosulfan LC50 0.05 6
Fenvalerate LC50 15 7
Glyphosate LC50 36800 8
Mancozeb LC50 11680 9
Cypermethrin 20% runoff 3.95 1
Deltamethrin 20% runoff 0.69 2
Actara 20% runoff 3.95 3
Carbofuran 20% runoff 78.99 4
Methomyl 20% runoff 10.86 5
Endosulfan 20% runoff 41.47 6
Fenvalerate 20% runoff 8.85 7
Glyphosate 20% runoff 14.22 8
Mancozeb 20% runoff 74.05 9
Cypermethrin 10% runoff 1.97 1
Deltamethrin 10% runoff 0.35 2
Actara 10% runoff 1.97 3
Carbofuran 10% runoff 39.49 4
Methomyl 10% runoff 5.43 5
Endosulfan 10% runoff 20.73 6
Fenvalerate 10% runoff 4.42 7
Glyphosate 10% runoff 7.11 8
Mancozeb 10% runoff 37.03 9

Answer 1

You can use the following code
library(scales)
library(tidyverse)
df$Concentrations <- factor(df$Concentrations, levels = c("10% runoff", "20% runoff", "NOEC", "LC50"))
df %>%
ggplot(aes(x = Pesticides, y = `Concentration (ug/L)`, fill= Concentrations)) +
geom_bar(stat = 'identity', position='dodge') +
scale_fill_discrete (breaks = c("10% runoff","20% runoff","NOEC", "LC50"))+
scale_x_discrete(guide = guide_axis(n.dodge=2)) +
scale_y_continuous(trans = log10_trans(),
breaks = trans_breaks("log10", function(x) 10^x),
labels = trans_format("log10", math_format(10^.x)))
Data
df = structure(list(Pesticides = structure(c(3L, 4L, 1L, 2L, 9L, 5L,
6L, 7L, 8L, 3L, 4L, 1L, 2L, 9L, 5L, 6L, 7L, 8L, 3L, 4L, 1L, 2L,
9L, 5L, 6L, 7L, 8L, 3L, 4L, 1L, 2L, 9L, 5L, 6L, 7L, 8L), .Label = c("Actara",
"Carbofuran", "Cypermethrin", "Deltamethrin", "Endosulfan", "Fenvalerate",
"Glyphosate", "Mancozeb", "Methomyl"), class = "factor"), Concentrations = structure(c(3L,
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L,
4L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L), .Label = c("10% runoff", "20% runoff", "NOEC", "LC50"
), class = "factor"), `Concentration (ug/L)` = c(4.8, 3.37, 20000,
40.6, 260, 10.2, 6.02, 5000, 301, 0.03, 0.032, 322000, 500, 4015,
0.05, 15, 36800, 11680, 3.95, 0.69, 3.95, 78.99, 10.86, 41.47,
8.85, 14.22, 74.05, 1.97, 0.35, 1.97, 39.49, 5.43, 20.73, 4.42,
7.11, 37.03), Individual = c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L,
9L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 1L, 2L, 3L, 4L, 5L, 6L,
7L, 8L, 9L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L)), row.names = c(NA,
-36L), class = "data.frame")