The complementing components of the 20th WCSS logo form a rectangle reflecting the soils and agricultural fields with the four trigrams depicting the agricultural ecosystem and vital activities occurring inside. Originating from oriental philosophy, the four trigrams symbolize the four universal elements and key components of the environment: upper left( :Sky, Spring, East, Tree), lower right ( :Earth, Summer, West, Fire), lower left ( :Sun, Autumn, South, Metal) and upper right ( :Moon, Winter, North, Water). They reflect the key components of the agricultural ecosystem such as plants, rivers, rolling hills and contours, etc.; the live organisms in soil such as earthworms, grubs and roots, etc.; and major practices such as strip-crops, plowing, windrows and erosion gullies, etc. There is a unity among them through form of shape and style as they interact in harmony. In addition, the four trigrams represent the four divisions of IUSS. The logo is a montage of soils embracing life and universe, which has inspired the theme of the 20th WCSS.