Presenting major cations and anions in soil or water samples through Maucha Diagrams

 

A Maucha diagram, or Maucha symbol, is a graphical representation of the major cations and anions in a chemical sample. The star shape diagram comprises eight kite-shaped polygons, the area of each of which is proportional to the concentration of an ion in milliequivalents per litre. The anions carbonate, bicarbonate, chloride and sulphate are on the left, while the cations potassium, sodium, calcium and magnesium are on the right. The total ionic concentration adds up to the area of the background circle, the total anion concentration adds up to the left semicircle and the total cation concentration adds up to the right semicircle.

A package “oviz” is available in ‘github’ for developing Maucha diagram. We need to install it from github.

devtools::install_github("fkeck/oviz")

Once installed, load the library

library(oviz)

Now, set your working directory using function “setwd( )”.

path<- ("E:\\Blog")     # Write your working directory path here

setwd(path)

Do notice the “\\” in the path. It’s not “\”.

You can use “/” too instead of “\\”.

Next, read your data on cations and anions. I have used a data with four soil water samples in this blog and named it “soil water ions” and saved it as .csv format. 

K	Na	Ca	Mg	SO4	Cl	HCO3	CO3
1.9	576.1	0.8	1	2	1	496	132
1.1	80.4	2	2	14	10.5	36	8
0.7	145.7	1	0.2	12	0.8	56	8
0.4	23.9	1	0.6	18	0	0	28

You may prepare your data in the same fashion.

The order of the ions should be as K⁺, Na⁺, Ca⁺⁺, Mg⁺⁺, SO4^--, Cl^-, HCO^-₃, CO₃^--.

The names of the fields should be as K, Na, Ca, Mg, SO4,    Cl, HCO3, CO3.

 

Import the data

mydata<-read.csv("soil water ions.csv", header = TRUE)
mydata

##     K    Na  Ca  Mg SO4   Cl HCO3 CO3
## 1 1.9 576.1 0.8 1.0   2  1.0  496 132
## 2 1.1  80.4 2.0 2.0  14 10.5   36   8
## 3 0.7 145.7 1.0 0.2  12  0.8   56   8
## 4 0.4  23.9 1.0 0.6  18  0.0    0  28

Now we can prepare the Maucha diagram.

Use the function “maucha( )” to generate the diagram.

maucha(data)

In the first and third plots, there are more Na⁺ and HCO^-₃ ions. In the fourth sample Na⁺ and CO₃^2-  ions dominate.  The second sample has higher Na⁺ and anions in almost equal concentration.

You can explore the package help page.

You can also consult the following book for various infographics to represent the soil water cations and anions and many more things related to infographics in soil science.

Soil Data Visualization with R, Brillion Publishing, New Delhi