Calculating two LM in one plot using stat_poly_eq

Question

I have calculated linear regression models between soil acetone emission and soil carbon content and plotted this in a graph like this:

Instead of showing one regression model in the plots I would like to show one for organic and one for mineral soil in the same plot. E.g. with different colours.

Any ideas? All help is much appreciated!

Here's the code for the plot:

library(ggplot2)
library(ggpmisc)

 formula <- y~x

(p1 <- ggplot(df, aes(carbon, acetone)) +
    geom_smooth(method = "lm",formula = formula, col="black") +
    geom_point() +
    theme_bw() +
    facet_wrap(~days)+
    stat_poly_eq(
      aes(label = paste(stat(adj.rr.label), stat(p.value.label), sep = "*\", \"*")),
      formula = formula, rr.digits = 1, p.digits = 1, parse = TRUE,size=3.5))

Here's the data:

df <- structure(list(carbon = c(22, 19, 21, 3, 45, 25, 24, 72, 1, 63, 
13, 69, 6, 4, 11, 8, 8, 9, 9, 5, 164, 17, 8, 4, 2, 7, 1, 14, 
88, 16, 1, 115, 4, 4, 3, 2, 1, 2, 80, 29, 5, 8, 1, 2, 4, 17, 
19, 7, 22, 19, 21, 3, 45, 25, 1, 63, 13, 69, 6, 4, 11, 8, 8, 
9, 9, 5, 16, 17, 8, 4, 2, 7, 1, 14, 88, 16, 1, 115, 4, 4, 3, 
2, 1, 2, 80, 296, 5, 8, 1, 17, 19, 7), acetone = c(12, 12, 8, 
17, 60, 260, 65, 171, 0, 30, 13, 0, 56, 3619, 
200, 20, 448, 242, 175, 265, 9, 19, 23, 14, 30, 162, 
16, 299, 0, 0, 120, 17, 307, 57, 0, 8, 4, 44, 98, 2, 
10, 385, 91, 130, 21, 12, 65, 181, 3, 5, 0, 44, 24, 11, 
0, 0, 0, 0, 531, 0, 0, 2, 30, 4, 2, 29, 12, 0, 87, 13, 0, 0, 
0, 105, 155, 198, 0, 0, 0, 0, 0, 0, 5, 2, 50, 0, 31, 0, 0, 
126, 70, 0), days = c(10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 
10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 
10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 
10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 
10L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 
94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 
94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 94L, 
94L, 94L, 94L, 94L, 94L, 94L), soil_type = c("organic", "mineral", 
"organic", "mineral", "mineral", "mineral", "mineral", "organic", 
"mineral", "organic", "mineral", "mineral", "mineral", "mineral", 
"mineral", "mineral", "mineral", "mineral", "mineral", "mineral", 
"organic", "mineral", "mineral", "mineral", "mineral", "mineral", 
"mineral", "mineral", "organic", "mineral", "mineral", "organic", 
"mineral", "mineral", "mineral", "mineral", "organic", "mineral", 
"mineral", "organic", "mineral", "organic", "mineral", "mineral", 
"mineral", "organic", "mineral", "mineral", "organic", "mineral", 
"organic", "mineral", "mineral", "mineral", "mineral", "organic", 
"mineral", "mineral", "mineral", "mineral", "mineral", "mineral", 
"mineral", "mineral", "mineral", "mineral", "organic", "mineral", 
"mineral", "mineral", "mineral", "mineral", "mineral", "mineral", 
"organic", "mineral", "mineral", "organic", "mineral", "mineral", 
"mineral", "mineral", "organic", "mineral", "mineral", "organic", 
"mineral", "organic", "mineral", "organic", "mineral", "mineral"
)), row.names = c(NA, -92L), class = "data.frame")