John Christopher Augustus Voelcker FRS (24 September 1822 – 5 December 1884) was a Royal Agricultural Society of England chemist. Voelcker was known for his methodical and precise analytical practices as applied to agricultural chemistry. He began a series of long-term experiments at Woburn on crop rotation and fertilization in 1876. This was continued after his death in 1884 by his son John Augustus Voelcker (1854-1937) who was also an agricultural chemist who later headed a committee that investigated improvements to agriculture in India.