Experimental control of plant nutrient status using programmed nutrient addition

Abstract

In simple non-renewed water culture systems, large changes in plant nutrient status may occur during the course of an experiment due to depletion of the nutrient solution. These changes complicate the study of effects of nutrient status on physiological processes. Flowing solution culture techniques offer one solution to the problem, but these techniques tend to be laborious and require equipment not available at most laboratories. Programmed Nutrient Addition is a simple, low-cost technique for controlling plant nutrient status. In this technique frequent, small additions of all nutrients are made, including the test element. In this way, plant nutrient status is held approximately constant or is varied in a predetermined manner. Computer software has been developed for generating schedules of nutrient addition given information on the growth curve of the plant species being studied, approximate tissue concentrations needed for healthy growth, and the level of stress (if any) intended. The paper discusses the Programmed Nutrient Addition technique which has been applied successfully over the past 16 years in studies on several species including grain sorghum (Sorghum bicolor L.), sunflower(Helianthus annuusL.), cotton (Gossypium sp.), cassava (Manihotesculenta Crantz), kiwi fruit (Actinide TchinensisPIanch), and ginger (Zingiberofficinale Roscoe)