[R] error MANOVA in R

[Gian Maria Niccolò Benucci]

Dear R-usrs,

I am trying to perform a MANOVA on a data frame with 31 columns about soil
parameters and 1 column containing the explanatory variable (Fraction) that
have three levels.
my code is the following:

datam <- read.table("data_manova2.csv", header=T, sep=",")
names(datam)

manova_fraction2 <- manova(cbind(pH, AWC, WEOC, WEN, C.mic, CO2.C, Ca, Mg,
K, Na, sol.exch.Fe, easily.reducible.Fe, amourphou.Fe.oxide...Fe.OM,
crystalline.Fe.oxides, TN, TOC, NH4.N, NO3.N, N.org, organic.P, avaiable.P,
Total.PLFA, Tot.Bat, Gram., Gram..1, Funghi, AMF, protozoa, actinomiceti,
non.specifici) ~ as.factor(Fraction), data= datam)

summary(manova_fraction2)

when I did the summary I got this error

> summary(manova_fraction2)
Error in summary.manova(manova_fraction2) : residuals have rank 18 < 30

​Is this error possibly due to high correlation between my variables?

Many thanks in advance,


-- 
Gian

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