WARNA TANAH

 

T secara langsung mempengaruhi penyerapan sinar matahari dan salah satu faktor penentu suhu tanah

T secara tidak langsung berhubungan dengan sifat-sifat tanah, misal informasi subsoil drainase, kandungan bahan organik surface horizon, pembeda antar horison

T diukur dengan menggunakan standar warna (Soil Munsell Color Chart)

T Keterangan Soil Munsell Color Chart :

“ The Munsell notation identifies color by use of three variables : Hue, Value, and Chroma.

Hue is the dominant spectral color, that is, whether the hue is a pure color such as yellow, red, green or a mixture of pure color, such as yellow-red. Mixtures are identified numerically according to the amount of yellow or red used to produce the mixture. 5YR is an equal of red and yellow. As the number increases, the amount of the first color (yellow) increases and the second color (red) decreases.

Value and Chroma are terms that refer to how the hue is modified by the addition of gray.

Value is the degree of lightness or brightness of the hue reflected in the property of the gray color that is being added to the hue. A particular value (gray) is made by mixing a pure white pigment (10) with a pure black pigment (0). If equal amounts of white and black pigments are mixed, the value is equal to 5.

Chroma is the amount of gray of a particular value that is mixed with the pure hue to obtain the actual soil color. A chroma of 1 would be made by adding 1 unit of pure hue to a certain amount of gray; a chroma of 5 would contain 5 units of pure hue to the amount of gray. The lower the chroma, the closer the color is to the pure gray of that value. “

 

T Interpretasi : Warna tanah disebabkan oleh adanya bahan organik, dan atau status oksidasi senyawa besi dalam tanah.

T tanah yang dibentuk oleh bahan induk basalt sering berwarna sangat gelap jika tanah tersebut mengandung sedikit atau tidak ada bahan organik

T Status oksidasi besi terutama di lapisan bawah : tanah yang aerasi dan drainase bagus, senyawa besi berada dalam bentuk oksidasi (Ferri/Fe³⁺) dan memberikan warna merah atau kuning; tanah yang aerasi dan drainase jelek, senyawa besi tereduksi dalam bentuk ferro (Fe2+) akan memberikan warna abu-abu (gray)

 

T Hubungan antara warna tanah dengan kandungan bahan organik di Illinois, USA

 

Notasi Munsell (kondisi lembab)	Bahan Organik (%)
	Range	Average
10 YR 2/1	3,5-7,0	5,0
10YR 3/1	2,5-4,0	3,5
10 YR 3/2	2,0-3,0	2,5
10 YR 4/2	1,5-2,5	2,0
10 YR 5/3	1,0-2,0	1,5