Deficient, Adequate and Excess Nitrogen Levels Established in Hydroponics for Biotic and Abiotic Stress-Interaction Studies in Potato

Application of mineral nutrients to improve plant health is critical to providing food and fiber. Potato (Solanum tuberosum L.) is among the most responsive species to N application but is susceptible to biotic and abiotic stresses. Nitrogen-stress relationships are generally evaluated indirectly during field fertility trials designed for collection of agronomic data. A controlled environment system would benefit understanding N nutrition-stress interactions. Environmental chamber hydroponics allows strict experimental control of temperature, humidity, light, etc. while maintaining specific N nutrition. Potatoes were grown at various N levels. Plant biomass had a curvilinear relationship with N supply, peaking at 80 mg N L-1. Root or shoot N regressed against solution N produced significant, predictable relationships (R-2 > 0.98 for each). Such relationships provide a basis to conduct controlled N nutrition-abiotic-biotic stress studies that could delineate among stress factors. This work establishes the specific ranges of N needed to complete such research.