His work spanned 50 years and involved soil mapping, fertiliser development and agricultural research, and he was involved in both the academic and commercial soil science field.
After doing research for the Agricultural Research Council’s Institute for Soil, Climate and Water in Pretoria, Dr Botha was appointed Professor Honorér in the Department of Crop Production at the University of Pretoria. While there, he developed a practical method of irrigation for emergent farmers.
A member of the South African Fertiliser Society, Dr Botha he held the positions of agronomist, fertiliser adviser, manager agricultural services and technical director for various fertiliser companies. He was also a private consultant.
One of the highlights of his career was co-ordinating a five-year research programme between SA and the National Chung Hsing University of Taiwan.
He obtained his B.ScAgric cum laude from the University of Pretoria and his D.ScAgric from the same university. He leaves his wife Annette, three sons, Danie, Phillip and Abel, and a daughter, Marietjie, from a previous marriage, eight grandchildren and three stepsons, Stephan, Tian and Johan.