Both data frames have the same columns and independent rows so you don't want to "merge" them, you want to "bind" them, take a look at this example:
library(dplyr)
# Sample data in a copy/paste friendly format, replace this with your own data frames
data1 <- data.frame(
ID = c(1, 4, 6),
light = c(11, 11, 11),
lux = c(26, 26, 26),
time = c(19, 19, 19),
rdom = c(12, 12, 12),
f1 = c(2.1, 22.9, 6.6),
f2 = c(34, 31, 7)
)
data2 <- data.frame(
ID = c(2, 3, 5),
light = c(11, 11, 11),
lux = c(26, 26, 26),
time = c(19, 19, 19),
rdom = c(12, 12, 12),
f1 = c(2.8, 24.3, 9.2),
f2 = c(24, 34, 5)
)
# Relevant code
data1 %>%
bind_rows(data2) %>%
arrange(ID)
#> ID light lux time rdom f1 f2
#> 1 1 11 26 19 12 2.1 34
#> 2 2 11 26 19 12 2.8 24
#> 3 3 11 26 19 12 24.3 34
#> 4 4 11 26 19 12 22.9 31
#> 5 5 11 26 19 12 9.2 5
#> 6 6 11 26 19 12 6.6 7
Created on 2022-08-03 by the reprex package (v2.0.1)