Composted slaughterhouse sludge as a substitute for chemical fertilizers in the cultures of lettuce (Lactuca sativa L.) and radish (Raphanus sativus L.)

Abstract

Flotation sludge (FS) is produced in huge amounts at slaughterhouses in western Santa Catarina, Brazil. This waste is rich in plant nutrients and a valuable resource for soil amendments. Five FS composts were tested as a replacement for chemical fertilizers (QF), namely T1 (75% poultry manure (PM) and 25% sawdust (SD)); T2 (50% PM and 50% SD); T3 (25% PM and 75% SD); T4 (100% PM and 0% SD); and T5 (0% PM x 100% SD). For lettuce plants, treatments containing composted FS resulted in an increased number of leaves, leaf area and leaf fresh weight (LFW). T1 presented the best results with increases of 1.4 fold in LFW compared to plants supplemented with QF. T2 was the most effective treatment for radish with the best results of root fresh weight and root diameter. Although T4 had the highest nitrogen content, it did not present the best results in growth performance for lettuce or radish. The presence of higher proportions of SD in composts (25% for lettuce and 50% for radish) improved the physical characteristics of the soil and proved to be a more balanced compost.Keywords: biosolid; organic compost; poultry manure; sawdust; flotation sludge.Practical Application: Floatation sludge successfully replaced chemical fertilizers in the cultures of lettuce and radish.

Full-Scale Composting of Different Mixtures with Meal from Dead Pigs: Process Monitoring, Compost Quality and Toxicity

“…The tested materials were pig slaughterhouse sludge from a primary wastewater treatment system (coagulation, flocculation and centrifugation), eucalyptus sawdust from local logging companies and a stabilizing compost (used as an inoculum). These materials were mixed for composting in five treatments, all including a fixed 50% sawdust as the bulking agent and the main source of carbon: T1: sawdust and slaughterhouse sludge (50:50, v:v) was the control, since it was considered efficient in previous studies, based on physical-chemical stabilization [26] and absence of phytotoxicity [27]. T2: sawdust, slaughterhouse sludge and meal from dead pigs (50:20:30).…”

“…Nonetheless, the efficiency of composting cannot be evaluated considering only a single property, since physicochemical analyses and phytotoxicity assays are also relevant [25]. The efficiency of the composting treatments including sludge from agro-industrial wastewater treatment systems and sawdust was already reported [26,27]. However, considering that composts generated from treatments including meal from dead pigs may contribute to attenuate the dependence of agriculture on chemical fertilizers, the effects of the inclusion of such meals on the nutrient content and maturity of composts still needs to be investigated.…”

Comparison of nutrient use efficiency, antioxidant assay, and nutritional quality of butter-head lettuce (Lactuca sativa L.) in five cultivation systems

“…Lakhiar et al [21] concluded that the highest TPC values were achieved in air-assisted atomizer. TFC is mainly responsible for the antioxidants of food and leafy vegetables have higher values of it when cultivated in air-circulation system [54,56,57] . The antioxidant activity depends on the species, geographic origin, agricultural practices used, and cultivation systems [58] .…”

Bioactive compounds and antioxidant activity of crisphead lettuce (Lactuca sativa L.) of three different cultivation systems

“…Curly lettuce is a fresh vegetable consumed alone or in combination with other vegetables ready for consumption, usually consumed in mixed and fresh-cut salads. Depending on the leaf type and growing conditions, its edible leaves present high demand for nutrients (El-Nakhel et al, 2019;Oliveira et al, 2018;Patella et al, 2019).…”