Several agro-industrial, livestock, and food wastes can be recycled to create biofertilizers. This diversity of raw materials can result in nutritional imbalance and an increase in heavy metal content, which could make the final product unfeasible. Thus, the chemical characterization of the raw materials and their influence on the sustainable and safe production of biofertilizers need to be better understood. In this context, the objective of the present study was to evaluate the chemical characteristics of agro-industrial residues used in the manufacture of an aerobic liquid biofertilizer. We analyzed the macronutrient, micronutrient, and trace metal contents of seven waste products used as raw materials to create a biofertilizer. In addition, a survey of secondary biofertilizer data from different residues was carried out that showed great heterogeneity in the chemical compositions of these residues, which has a direct impact on the agronomic efficiency of these biofertilizers. The characterization revealed that some materials may be contaminants of the soil, due to high levels of trace metals, especially cadmium. We conclude that the generation of detailed inventories, such as those of the nutrient and heavy metal contents of the raw materials and biofertilizers produced, is indispensable for the correct recommendation of biologically-based inputs in agriculture.

Biofertilizers stimulate natural processes to increase and benefit nutrient absorption, abiotic stress tolerance and increased yield when applied to plants. The production of biofertilizers from organic residues is a sustainable way to reduce these materials through recycling. The aim of this work was to define the biofertilization management based on concentrations and doses using a non-commercial aerobic biofertilizer on three newly emerged Brazilian lettuce cultivars. Consequently, this study will help to improve organic lettuces yields in the country. The experiments were conducted in a greenhouse. The soil used for cultivation was a clayey Rhodic Ferralsol. Due to the high electrical conductivity (EC) observed in the biofertilizer a first experiment was conducted to determine the optimum concentration (0%, 5%, 10%, 15%, 20% and 100%) for the three lettuce cultivars (BRS Leila, BRS Lélia and BRS Mediterrânea). After finding the best concentration, a second experiment was developed to estimate the optimum dose of the biofertilizer based on the nitrogen requirement (N) for this crop (0 kg ha-1 of N, 50 kg ha-1 of N, 100 kg ha-1 N, 150 kg ha-1 N and 200 kg ha-1 N). The experimental design was completely randomized (DIC) with a factorial scheme. The results showed that 5% concentration of biofertilizer presented better results for the development of BRS Mediterrânea and BRS Lélia. BRS Leila presented better development when fertilized with the 10% biofertilizer concentration. The dose of 150 kg ha-1 of N allowed a better development of lettuce and greater supply of nutrients to the plants.

Root-knot nematode (RKN) is a serious threat to crops worldwide due to the difficulty in controlling it and the limited eco-friendly alternatives to deal with the biotic stress it causes. In the present work, water-extractable fractions obtained from vermicompost (WSFv), vermicompost enriched with Trichoderma asperellum (WSFta) and T. virens (WSFtv) were tested as biotechnological tools to reduce the impacts of RKN on gas exchange, water use efficiency (WUE) and nutrient concentration in tomato and bell pepper plants. The plants were infected with 5000 eggs and eventual J2 of RKN and then treated with the water-extractable fractions for seven weeks. It was observed that the addition of WSFta, WSFtv and WSFv increased the CO2 assimilation, stomatal conductance and WUE in the tomato plants. In the bell pepper plants, WSFta, WSFtv, WSFv increased the stomatal conductance, while WUE was higher in the treatment with WSFtv. In fact, the parameters associated with the gas exchange were usually higher in the bell pepper than in the tomato plants. Overall, higher contents of N, Mg, B and Mn were detected when the extracts were applied in both bell pepper and tomato plants. The application of the water-extractable fractions, inoculated or not with Trichoderma, attenuates the RKN damage on the gas exchange parameters and successfully enhanced the nutrient concentration in the infected tomato and bell pepper plants, showing that it could be an important and promising tool for reducing the damage caused by this pathogen. We suggest that both the tomato and pepper plants can cope with the dilemma between growth and stress response via stomata regulation that are modulated by the WSF and Trichoderma.

RESUMO -Objetivou-se avaliar o efeito do ozônio na qualidade de morango produzido em sistema orgânico. Os frutos foram submetidos a diferentes combinações de concentração e período de exposição ao gás, e armazenados em câmara fria a 5 °C por 12 dias. Avaliou-se o percentual de perda de massa fresca, teor de vitamina C e cor dos frutos. A ozonização influenciou a qualidade dos frutos, quando se considerou as variáveis de perda de massa fresca, teor de vitamina C e diferença de cor. O percentual de perda de massa fresca foi menos intenso nos frutos ozonizados. Não foi observado redução no teor de vitamina C nos frutos ozonizados nas concentrações de 1.000 e 2.000 ppm, por 60 e 30 minutos, respectivamente. Ocorreu aumento menos intenso da diferença de cor nos frutos ozonizados. A ozonização pode ser considerada uma importante alternativa para a manutenção da qualidade de morangos orgânicos.ABSTRACT: The objective of this research was to evaluate the effect of ozone on the quality of strawberry produced in an organic system. The fruits were subjected to different combinations of concentration and length of exposure to gas, and subsequently stored in a climate control chamber at 5°C for 12 days. The characteristics evaluated included percent loss of fresh mass, vitamin C content and fruit color. The ozonation influenced the quality of the fruit when it was considered the variables loss of fresh mass, vitamin C content and color difference. The percent fresh mass loss was lower in ozonated fruits. There was no reduction on vitamin C content in fruits ozonated at the concentrations of 1.000 and 2.000 ppm for 60 and 30 minutes, respectively. There was a less intense increase in color difference in ozonated fruits. Ozonation can be considered an important alternative for quality maintenance in organic strawberry. PALAVRAS-CHAVE: ozonização, alterações qualitativas, morango orgânico.

This study aimed to assess the nutrient dynamics of raw and treated wastewater (RWW and WW) in constructed wetlands (CW) for the irrigation of ornamental sunflowers, compared to freshwater (Fw) in Red Yellow Latosol (RYL) with (OF) and without (WF) inorganic fertilization. The study was carried out from July 10th to October 2nd of 2019. Wastewater was applied in pots with 10 kg of RYL. The amount of salts in the RWW, influent and effluent of CW and UnS (Uncultivated System), were evaluated in eleven samples. The study also assessed the following: plant height (PH), stem diameter (SD), number of leaves (NL), leaf area index (LAI), the inner diameter of the capitulum (IDc), the outer diameter of the capitulum (ODc), number of petals in the bud (NP), days after harvest (DAH), fresh phytomass in the aerial part (FPAP), dry phytomass in the aerial part (DPAP), fresh phytomass of the capitulum (FPc), dry phytomass of the capitulum (DPc), nutrient content in the aerial sunflower, and chemical composition in the RYL. The average removal efficiency of K+, Ca2+, and Fe in the CW was 34.33, 37.88, 39.82, and 45.40%, respectively. The PH (86.54 cm), SD (11.75 mm), NL (21), and LAI 3646.73 cm2) were higher in the WWOF treatment at 70 days after sowing. Treated wastewater without fertilization (WWWF) presented higher P, K, S, B, and Mn absorption. Freshwater with fertilization accumulated greater amounts of N, and WWOF accumulated greater amounts of Zn. Wastewater increased the P content and decreased K+ and Ca2+ in RYL. Irrigation with domestic WW in CW provided salts to the soil and increased the growth and quality of sunflowers irrigated with Fw