Influence of nutrient solution pH on hydroponic basil (Ocimum basilicum) plant growth and nutrient content
MetadataShow full item record
Other Titles:Root Zone Optimization of Hydroponic Leafy Greens
Series/Report no.:2019 Edward F. Hayes Graduate Research Forum. 33rd
The optimum pH range typically considered for hydroponic nutrient solution is 5.5-6.5. Outside this range, plants tend to show specific nutrient disorders due to nutrient availability and ion competition. Root diseases such as Pythium and Phytophthora spp. have been shown to be negatively affected by acidic conditions (e.g., pH <5.0). We hypothesize that if nutrient concentrations are adjusted properly based on availability levels at selected low pH, plants can be grown without nutrient disorders while certain root diseases may be suppressed. As the first step towards development of a new nutrient solution management strategy, we determined the influence of lower-than-conventional pH on plant growth and nutrient content as well as the efficacy of mitigating nutrient disorders by adjusting micronutrient concentrations in solution based on known availability levels. ‘Nufar’ basil plants were grown in a greenhouse hydroponic system. pH was maintained at 5.5, 5.0, 4.5 or 4.0. Two nutrient solutions (with and without micronutrient adjustments) were applied at each pH level, where concentrations of Cu, Zn, Mn, and B were decreased by one-half and Mo concentration was doubled in the adjusted solution. After 20-21 days, plants were harvested for analysis. Leaf concentration of P, Ca, Mg, S, Fe, Mn, B, Cu, and Zn decreased with decreasing pH, whereas K displayed the opposite trend, and N and Mo concentration did not display a consistent trend across selected pH. Micronutrient adjustments were effective in decreasing uptake of Mn and Cu. To our surprise, basil plants can grow at pH as low as 4.0 without showing significant reduction in growth (shoot mass, root mass, stem mass, height and number of leaves) or symptoms of nutrient disorders. A follow-up study is currently underway to determine if this management strategy of growing basil at pH 4.0 is effective in limiting growth of pathogenic organisms in nutrient solution.
Food, Agricultural, and Environmental Sciences (FAES): 1st Place (The Ohio State University Edward F. Hayes Graduate Research Forum)
A one-year embargo was granted for this item.