The excessive use of agrochemicals to increase yield and fruit quality can result in soil, freshwater, and groundwater
contamination. Designing and using new products based on microorganisms, such as rhizosphere bacteria, could reduce
intensive agrochemical application and subsequent potential contamination. Therefore, the effect of a biocontroller
(
Pseudomonas fluorescens) on the nutrient balance and yield quality of melon (
Cucumis melo
L.) was evaluated under
field conditions. Control and treatment plots without and with a biocontroller applied with an irrigation system were
assayed. Soils were monitored by physicochemical and biochemical analysis and plants by nutrient and yield quality
analysis during crop development.
Pseudomonas fluorescens application significantly promoted salt solubility (416 and
1128 μS cm
-1), available Cu concentration (3.8 and 4.3 mg kg
-1), P availability (104 and 123 mg kg
-1), and microbial C
biomass (56 and 93 mg C kg
-1) for control and treatment plots, respectively. In addition, biocontroller application did
not significantly increase soil total N and exchangeable Na, Mg, and K concentrations.
Pseudomonas fluorescens also
promoted Mn, N, Zn, and P absorption, which causes competition among nutrients, limiting Cu, Na, Ca, and K absorption
by melon plants. The β-glucosidase activity was also responsible for releasing Fe, Zn, Cu, Mn, P, and N in the soil.
Finally,
P. fluorescens application increased fruit size and weight (3.0 to 3.8 and 3.3 to 4.3 kg for control and biocontroller
treatments, respectively); therefore, biofertilization with this bacterium is a sustainable alternative to increase yield and
fruit quality without increasing the use of chemical fertilizers and pesticides.
