Natural Fertilizers and Algae Boost Organic Tomato Yield and Quality

Natural science news
2024.09.02

Microbial biofertilizers and algae-based biostimulants have been recognized for supporting sustainable agriculture. In recent field experiments conducted in the 2022 and 2023 growing seasons on an organic farm in Ferrara, Italy, researchers from the University of Ferrara evaluated the effects of plant growth-promoting microorganisms (PGPMs) and algae-based biostimulants on tomato plants (Solanum lycopersicum L.). This study aimed to determine whether these treatments could enhance plant growth and yield in an environmentally friendly manner.

The experimental setup included two microbial biofertilizers (PGPM_1 and PGPM_2) and a control group with no inoculated plants (No_PGPM). Additionally, two rates of algae-based biostimulants (0.5% (Biost_0.5%) and 1.0% (Biost_1.0%)) were tested against a no-application control (No_Biost). PGPMs were applied at transplanting, while biostimulants were administered 15 and 30 days after transplanting. Plant characteristics were evaluated 30 days after transplanting, and various growth parameters, including soil plant analysis development (SPAD), nitrogen difference vegetation index (NDVI), leaf area index (LAI), and photosynthetic photon flux density (PPFD), were monitored throughout the cultivation period. Tomato yield was also determined.

The results showed that PGPM_2 led to the highest shoot biomass (132.9 g per plant), plant height (44.7 cm), leaf number (34 per plant), and root biomass (9.22 g per plant). Intermediate values were observed in PGPM_1, while all parameters were lower in the No_PGPM group. Both PGPM treatments achieved higher SPAD, NDVI, PPFD, and LAI values compared to the control. Among the biostimulants, Biost_1.0% resulted in the highest growth parameters, followed by Biost_0.5%, and then No_Biost. The highest tomato yield was recorded for the treatment combining PGPM_2 and Biost_1.0% (67.2 tons per hectare). Additionally, PGPMs influenced fruit size and sugar content, while biostimulants were linked to improvements in color and lycopene content.

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