He causeth the grass to grow for the cattle,
and herb for the service of man:
that he may bring forth food out of the earth;
Psalm 104:14
The 2 primary colors that blanket the earth-Green & Brown, are soothing colors. The Creator coverd the earth with them with the foilage. Then He sprinkled in some various colored plants here & there for beauty.
Green strikes the eye in such a way as to require no adjustment whatever and is, therefore, restful. Being in the centre of the spectrum, it is the colour of balance.
BROWN
Brown usually consists of red and yellow, with a large percentage of black. It is a reliable color and most people find it quietly supportive.
coloureffect.com.uk