Response of crop growth to microalgae in irrigation water.

Abstract

Microalgae synthesize numerous bioactive compounds which are used in various industries. There are numerous successful applications of microalgae in the agriculture industry and it is well documented that microalgae promote crop growth as a bio-fertilizer. Recently, companies are marketing microalgae products as both a bio-fertilizer and plant bio-stimulant that promote and optimize crop growth. However, there are no empirical data that document the plant bio-stimulant effects of microalgae on crop growth. The objective of this study was to assess whether microalgae stimulated crop growth and flowering parameters and determine if it acts as a bio-fertilizer and-or plant bio-stimulant. Two crops were used, Radish (Raphinus sativus) and French marigold (tagetes sp.). In the radish experiment five treatments were tested: a control (DW) and four different microalgae treatments (T1, T2, T3 and T4). In the French marigold experiment ten treatments were tested: control (DW), four microalgae treatments (T1, T2, T3 and T4), synthetic fertilizer (150ppm N, P, and K respectively), and four combination treatments of synthetic fertilizer with each microalgae treatment (T6, T7, T8 and T9). Results showed that the microalgae treatments stimulated radish and French marigold growth parameters, but statistical analysis did not show any significant differences among plants treated by the various microalgae treatments. Similarly, analysis did not show any significant difference between marigold plants treated with synthetic fertilizers and plants treated by the combination treatments. The obtained results do not support claims by companies that microalgae promote crop growth as a plant bio-stimulant. However, when applied to the soil, the microalgae stimulated crop growth parameters as a bio-fertilizer.