Growth and biochemical responses of moringa (Moringa oleifera L.) to vermicompost and phosphate rock under water stress conditions

The aim of this investigation was to analyze the effect of vermicompost and phosphate rock on plant growth and biochemical responses of Moringa oleifera exposed to water deficit and waterlogging conditions. Treatments included 152 g of vermicompost (V) and 1.3 g of phosphate rock (PR) added to each cultivation bag. Control was prepared with 2.3 g of urea. All treatments were irrigated under different watering conditions [water deficit: irrigated at 20% water holding capacity (WHC); control (40% WHC) and waterlogging (60% WHC)]. The overall average in plant height was 90, 86 and 68 cm, whereas chlorophyll was 45, 40 and 39 Spad units under water deficit, control and waterlogging conditions, respectively. Proline concentration in M. oleifera leaves was higher in the V+PR treatment under water deficit conditions. Catalase and peroxidase activity were higher in plants cultivated under waterlogging conditions. Enzyme activities on plants cultivated under water deficit were not different in comparison to control plants. In conclusion, vermicompost was able to minimize the harmful effects of waterlogging. The application of vermicompost and phosphate rock in M. oleorifera favored the synthesis of catalase and peroxidase, and inhibited the accumulation of reactive oxygen species (ROS), thus protecting the plant from membrane damage and oxidative stress under waterlogging conditions.