Arnon L. Mehring, 90, a fertilizer chemist who was a retired Agriculture Department official and who was active in professional and civic organizations, died of cardiac arrest Feb. 26 in his home in Adelphi.

Mr. Mehring worked for Agriculture for 34 years before retiring as a staff specialist with the commodities stabilization board in 1956. He had spent the great bulk of his career in the bureau of soils' fertilizer division.

He was the author of several books and more than 150 technical articles and bulletins on fertilizer chemistry and statistics. He was a past president of the Washington chapter of the American Institute of Chemists and had been chairman of the national division of fertilizer and soil chemistry of the American Chemical Society.

Mr. Mehring was a native of Pennsylvania and moved to this area about 70 years ago. He lived in Hyattsville for 43 years before moving to Adelphi in 1963. He was a 1922 graduate of George Washington University. He was an Adelphi council member from 1930 to 1938, a public library trustee from 1938 to 1951, and a former Hyattsville police commissioner. He was a past master of Mt. Herman Masonic Lodge No. 179 in Hyattsville.

Survivors include his wife, Estelle of Adelphi; a son, Arnon Jr. of Flanders, N.J.; two daughters, Dorothea Pywell of Silver Spring, and Mildred Bright of Riverdale Heights; a brother, John S. of Elkton; seven grandchildren, seven great-grandchildren, and four great-great-grandchildren.