An automated relative-addition rate nutrient-dosing system for use in flowing solution culture

Abstract

An inexpensive but versatile system is described which uses a microcomputer to control eight peristaltic pumps to dose plants growing in flowing solution culture with different fixed or relative addition rates of nutrients, using dosing frequencies between 5 min and once a day. A brief account is given of its use in controlling relative addition rates of nitrate-nitrogen between 0.03 to 0.12d-1, using hourly nitrate solution additions, during 5 weeks of vegetative growth by perennial ryegrass (Lolium perenne L.). An assessment is made of its performance during this experiment, showing an overall accuracy within 5% of the intended dosage.