Dennis Robert HoaglandBorn 2 Apr 1884; died 5 Sep 1949 at age 65.American plant physiologist who was an authority on plant and soil interactions. He recognized early that the complex problems of soil and plant interrelations must be studied with rigid experimental control and the isolation of individual variables. Thus, he perfected the water-culture technique for growing plants without soil, which nutrient solution is still in plant physiology research. He collected much data on the influence of oxygen, temperature, light, and other factors on ion absorption by roots. In the late 1930's, he adopted radioactive isotopes as tracers. In his fieldwork on soil chemistry he studied zinc, potassium, and phosphate deficiencies of fruit trees in California. He influenced further intensive study of aspects of micronutrients (trace elements). |
