Abstract
AimsThe aim of this work was to evaluate the fertilizing effect of three anaerobic co-digestates on the growth of the herbaceous plant Lolium rigidum.MethodsNine treatments, combining different nutritional solutions (organic and inorganic) and number of fertilizations (one or two) were evaluated. Organic nutritive solution: plants grown with different olive mill solid waste (OMSW) -microalgae co-digestates: 75% OMSW-25% Raphidocelis subcapitata, volatile solids (VS) basis (OMSW-Rs); 50% OMSW- 50% Chlamydomonas Reinhardtii, VS basis (OMSW-Chl); and 75% OMSW-25% Secenedesmus quadricauda, VS basis (OMSW-Sq). Inorganic nutritive solution (INS): plants grown with inorganic Hoagland nutrient solution at 50%. After 60 days of experimentation, biometric and nutritional characteristics and photosynthetic activity were measured.ResultsThe results showed a favourable growth, development and nutritional quality of L. rigidum plants when digestates obtained from the anaerobic co-digestion of OMSW-microalgae are used as organic nutritional solutions as opposed to INS ones. The highest total biomass of L. rigidum was obtained with the treatments that involved two fertilizations. No inhibition due to excess nutrients was observed. A higher root/shoot ratio was achieved with the digestates of OMSW-Rs and OMSW-Ch as compared to that obtained with OMSW-Sq (F = 17.23 p ≤ 0.001). The nitrogen shoot biomass obtained after the organic treatments with the above-mentioned co-digestates was higher than that obtained after the inorganic treatment. Net photosynthesis rates did not present differences in the co-digestates treatments, being equal or superior to the INS treatments.ConclusionsThe use of the anaerobic co-digestates from OMSW-microalgae can be considered a viable and promising alternative to inorganic fertilization.
Highlights
The use of inorganic fertilizers has been and continues to be a very common practice among farmers
Significant differences in height were found among the different treatments (F = 6.13; p ≤ 0.001)—the values found after two fertigations were significantly higher (37–43 cm) than those obtained in the treatments that received only one fertigation (31–35 cm)
Regarding the relative growth rate (RGR) of the aerial part, the values were significantly higher with two fertigation than when only one was performed (F = 59.70; p ≤ 0.001), and no significant differences in RGR values were found among the different treatments (p ≥ 0.05)
Summary
The use of inorganic fertilizers has been and continues to be a very common practice among farmers. The establishment of policies to implement circular economy models that allow greater use of natural resources began in 2015 These models are aimed at addressing all phases of the life cycle of a product: from production, through consumption, waste management and the secondary raw materials market, with the objective of promoting and increasing the use of reprocessed nutrients and to support the development of circular economy with a more resource-effective use of nutrients. For this reason, it is necessary to return to the initial organic fertilization practices or to look for alternative organic fertilization sources, such as the use of the digestates from anaerobic digestion processes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
