Organic Fertilizer Sources Distinctively Modulate Productivity, Quality, Mineral Composition, and Soil Enzyme Activity of Greenhouse Lettuce Grown in Degraded Soil

Abstract

Intensive greenhouse vegetable production is often associated with a decline of crop productivity due to the increase of soil salinity and/or a reduction of biological fertility. The aim of the current work was to assess the effects of three organic fertilizers on morpho-physiological and agronomic traits of greenhouse lettuce as well as soil enzyme activity under poor soil quality conditions. The tested organic fertilizers (poultry manure, vinasse-based fertilizer, and insect’s frass fertilizer) were applied pre-planting at the same equivalent nitrogen (N) rate (90 kg N ha−1). Laboratory incubation assay results showed that vinasse-based fertilizer was the most suitable fertilizer in supplying the mineral N in the short term. All fertilizers increased shoot fresh and dry weight compared to unfertilized control with a more pronounced effect (+75%) with vinasse-based fertilizer and insect’s frass. Insect frass reduced by 27% the leaf nitrate concentration in comparison with the other treatments. The toxic heavy metal Pb was 46% lower in all organically fertilized lettuce leaves. Soil enzymatic activities of acid phosphatase, alkaline phosphatase, arylsulfatase (ArS), N-acetyl-β-D-glucosaminidase (NAGase), dehydrogenase, and total hydrolase (THA) were enhanced by poultry manure and insect’s frass in comparison with unfertilized control while vinasse-based fertilizer increased ArS, NAGase, and THA. Taken together, our data demonstrate that the application of organic fertilizers especially vinasse-based fertilizer and insect’s frass during intensive crop production is a suitable approach for mitigating the negative impact of soil salinity, enhancing soil biological fertility, and improving agronomic performance of greenhouse lettuce.

Enhancing Biometric Characters of Perennial Sweet Pepper (Capsicum annuum L.) Treated by Potassium Silicate and Vinasse Grown under Greenhouse Conditions

“…Spinach and barley yielded higher fresh and dry matter when treated with vinasse and recommended fertilizers compared to conventional fertilization alone [52]. A study on greenhouse lettuce demonstrated that vinasse-based fertilizer had a more pronounced effect (+ 75%) on shoot fresh and dry weight compared to poultry manure [53]. Similarly, applying 125 mg/l of Si to the pepper nutrient solution improved leaf area [12].…”

Insect-based agri-food waste valorization: Agricultural applications and roles of insect gut microbiota

“…Specifically, it was found to reduce the nitrate concentration in the leaves, indicating a potential role for insect frass in activating nitrogen assimilation in plant cells. Additionally, the application of BSF frass improved soil biological fertility, as evidenced by increased active carbon levels and enzyme activity involved in nutrient cycling [ 85 ].…”

Eco-Sustainability of Soils in Baby-Leaf Crop Systems under Tunnel through the Application of C-Rich Inputs: Towards Combating Soil Degradation

“…The main Italian area involved in Horticulturae 2024, 10, 476 2 of 19 the cultivation of leafy vegetables for the ready-to-eat sector (IV gamma) is the Sele River Valley, south of Salerno, where about 5.400 ha of plastic tunnel-greenhouses are dedicated to this purpose [5]. The adoption of intensive agriculture systems in tunnel-greenhouses for a long period may lead to a deterioration in the physical, chemical and biological quality of soil, which in turn, may negatively affect crop yield and quality [6,7].…”