Appraisal of Biodegradable Mulching Films and Vegetal-Derived Biostimulant Application as Eco-Sustainable Practices for Enhancing Lettuce Crop Performance and Nutritive Value

Abstract

Scientists, extensions specialists, and growers are seeking sustainable agricultural practices that are able to cope with these objectives in order to ensure global food security and minimize environmental damage. The use of mulching films and plant biostimulants in agriculture seems to be a valid solution for tackling these rising concerns. A greenhouse experiment was conducted in order to elucidate the morpho-physiological and nutritive characteristics of lettuce (Lactuca sativa L.) in response to foliar application of a tropical plant extract (PE) biostimulant and the use of plastic mulches. Two biodegradable mulch treatments (Mater-Bi® 1 and Mater-Bi® 2) were compared to black polyethylene (LDPE) and bare soil. Biodegradable mulch film Mater-Bi® 1 produced a comparable marketable fresh yield to the commercial standard polyethylene (LDPE), whereas Mater-Bi® 2 exhibited the highest crop productivity. When averaged over biostimulant application, lettuce plants grown with biodegradable film Mater-Bi® 2 exhibited superior quality traits in terms of K, Ca, total ascorbic acid, and carotenoids content. The combination of film mulching (LDPE, Mater-Bi® 1 or Mater-Bi® 2) with the tropical plant extract biostimulant exhibited a positive and significant synergistic effect (+30%) on yield. The PE-biostimulant induced higher values of SPAD index and total chlorophyll content when compared to untreated greenhouse lettuce. The mineral content of leaf tissues was greater by 10% and 17% (for P and Ca, respectively) when compared to the untreated lettuce (no PE application). Nitrate content was significantly reduced by 23% in greenhouse lettuce plants receiving PE as compared to the untreated control. The positive effect of Mater-Bi® 2 film on the ascorbic acid content has also been highlighted when combined with the biostimulant application, where a major amplification of total ascorbic acid (+168%) was recorded in comparison to the untreated lettuce. Overall, our work can assist leafy vegetables growers in adopting good agricultural practices, such as biodegradable plastic mulches and vegetal-derived biostimulants, to improve the sustainability of greenhouse production.

Linking abiotic stress, plant metabolites, biostimulants and functional food

“…Carillo et al (2019) found an increase in chlorophyll b, anthocyanins, and polyphenols in jute grown in half‐ and quarter‐nutrient solution conditions, because of the application of vegetal‐derived biostimulant from a tropical plant extract (Auxym®). The same biostimulant improved functional quality of greenhouse lettuce nutritive value related to enhanced antioxidant activity and health‐promoting secondary metabolites (Cozzolino et al, 2020). In the research of Kulkarni et al (2019), treatment of spinach ( Spinacia oleracea L. var Viroflay) with commercial seaweed product Kelpak © significantly increased free phenolics, salicylic and sinapic acid, the later one is known by its beneficiary effects in controlling diabetes.…”

Systematic Investigation of the Effects of Seven Plant Extracts on the Physiological Parameters, Yield, and Nutritional Quality of Radish (Raphanus sativus var. sativus)

“…Biostimulants have become more popular in sustainable agriculture in recent years because of their beneficial properties. They stimulate various physiological processes that promote nutrient acquisition and utilization by plants; enhance the root development (the length and number of root hairs), shoot development, yield, and nutritional quality of plants; counteract the effects of biotic and abiotic stresses; improve the activity of soil microbiota; and reduce the use of fertilizers and the content of undesirable compounds (e.g., nitrates and heavy metals) in cultivated plants (Ertani et al, 2014;Bulgari et al, 2015;Paradiković et al, 2018;Rouphael et al, 2018;Szparaga et al, 2018;Carillo et al, 2019a,b;Ekin, 2019;Shukla et al, 2019;Cozzolino et al, 2020). The effects of biostimulants may differ, depending on the plant species (e.g., different leaf permeability levels), cultivar, physiological stages, type of product, dose, concentration, time, and application method (e.g., foliar, soil drench, or seed treatment), as well as environmental conditions (Ertani et al, 2014;Bulgari et al, 2015;Paradiković et al, 2018;Szparaga et al, 2018).…”

Foliar application of plant-based biostimulants improve yield and upgrade qualitative characteristics of processing tomato

“…More researches reported that the application of vegetal-based biostimulants on lettuce and tomato determined a significant increase of the nutritional and functional quality of edible tissues (Cozzolino et al 2020;Caruso et al 2019b). Also, Di Mola et al (2020b) reported that the foliar application of biostimulants, especially seaweed extract and protein hydrolysates, improved the quality of baby leaf lettuce grown under different nitrogen levels, including non-fertilized ones.…”