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Fertilizers with enhanced efficiency or high-efficiency fertilizers increase the nutrient availability, minimize losses, and reduce costs, thereby increasing crop yields and food production while mitigating environmental impacts. This research evaluates the synthesis of biodegradable hydrogels from cassava starch and citric acid for agrochemical applications. Hydrogels were synthesized using water as the solvent and applied for the controlled release of macronutrients (N and K). Four concentrations of nutrient-containing salts were tested (0.5 to 10.0% w/w). Materials were analyzed using ATR-FTIR spectroscopy and swelling studies. The presence of nutrients reduced both the crosslinking efficacy and the water absorption capacity, with the latter dropping from 183.4 ± 0.6% to 117.9 ± 3.7% and 157.4 ± 25.0% for hydrogels loaded with NH4Cl and KCl, respectively. The cumulative release of K and N from the hydrogel was monitored for 144 h and examined using kinetics models, revealing that the releases follow Fickian's diffusion and anomalous diffusion, respectively. Additionally, the material was formed using cassava with peel previously milled to reduce the production costs, and its potential for nutrient-controlled delivery was evaluated, with the finding that this hydrogel decreases the release rate of nitrogen. The results suggest that these biomaterials may have promising applications in the agrochemical industry in the making of high-efficiency fertilizers.

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Antimicrobial resistance (AMR) is one of the main global health challenges. Anaerobic digestion (AD) can significantly reduce the burden of antibiotic resistance genes (ARGs) in animal manures. However, the reduction is often incomplete. The agronomic use of digestates requires assessments of their effects on soil ARGs. The objective of this study was to assess the effect of digestate on the abundance of ARGs and mobile genetic elements (MGEs) in the rhizosphere of ryegrass (Lolium perenne L.) and to determine whether half-dose replacement of digestate with urea (combined fertilizer) can be implemented as a safer approach while maintaining a similar biomass production. A greenhouse assay was conducted during 190 days under a completely randomized design with two experimental factors: fertilizer type (unfertilized control and fertilized treatments with equal N dose: digestate, urea and combined fertilizer) and sampling date (16 and 148 days after the last application). The results indicated that the digestate significantly increased the abundance of clinical class 1 integrons (intI1 gene) relative to the unfertilized control at both sampling dates (P < 0.05), while the combined fertilizer only increased them at the first sampling. Sixteen days after completing the fertilization scheme only the combined fertilizer and urea significantly increased the biomass production relative to the control (P < 0.05). Additionally, by the end of the assay, the combined fertilizer showed significantly lower levels of the macrolide-resistance gene ermB than digestate and a cumulative biomass similar to urea or digestate. Overall, the combined fertilizer can alleviate the burden of integrons and ermB while simultaneously improving biomass production.

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The use of lignocellulosic residues, originating from sawdust, in composting sewage sludge for organic fertilizer production, is a practice of growing interest. However, few studies have explored the effect of the proportion of sawdust and sewage sludge raw materials on composting performance in the humification process. This study assessed the addition of sawdust in the sewage sludge composting process, regarding carbon content, presence of heavy metals, and humification of the organic compost. The experimental design employed was a randomized complete block design with five treatments featuring different proportions of organic residues to achieve C/N ratios between 30-1 (T1: 100% sewage sludge and 0% sawdust, T2: 86% sewage sludge and 14.0% sawdust, T3: 67% sewage sludge and 33% sawdust, T4: 55% sewage sludge and 45% sawdust, and T5: 46.5% sewage sludge and 53.5% sawdust) and five replications, totaling 25 experimental units. The addition of lignocellulosic residue in sewage sludge composting increased the levels of TOC and the C/N ratio, reduced the levels of pH, P, N, Na, Ba, and Cr, and did not interfere with the levels of K, Ca, Mg, S, CEC, labile carbon, and metals Fe, Zn, Cu, Mn, Ni, and Pb. The increase in the proportion of sawdust residue favored the degradation of aliphatic groups, increasing the presence of aromatic structures and reducing humification at the end of composting. The use of sawdust as a lignocellulosic residue in sewage sludge composting is a viable and efficient alternative to produce high-quality organomineral fertilizers.

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Understanding the efficacy of alternative phosphorus (P) sources in tropical soils is crucial for sustainable farming, addressing resource constraints, mitigating environmental impact, improving crop productivity, and optimizing soil-specific solutions. While the topic holds great importance, current literature falls short in providing thorough, region-specific studies on the effectiveness of alternative P sources in Brazilian tropical soils for maize cultivation. Our aim was to assess the agronomic efficiency of alternative P sources concerning maize crop (Zea mays L.) attributes, including height, shoot dry weight, stem diameter, and nutrient accumulation, across five Brazilian tropical soils. In greenhouse conditions, we carried out a randomized complete block design, investigating two factors (soil type and P sources), evaluating five tropical soils with varying clay contents and three alternative sources of P, as well as a commercial source and a control group. We evaluated maize crop attributes such as height, dry weight biomass, and nutrient accumulation, P availability and agronomic efficiency. Our results showed that, although triple superphosphate (TSP) exhibited greater values than alternative P sources (precipitated phosphorus 1, precipitated phosphorus 2 and reactive phosphate) for maize crop attributes (e.g., height, stem diameter, shoot dry weight and phosphorus, nitrogen, sulfur, calcium and magnesium accumulation). For instance, PP1 source increased nutrient accumulation for phosphorus (P), nitrogen (N), and sulfur (S) by 37.05% and 75.98% (P), 34.39% and 72.07% (N), and 41.94% and 72.69% (S) in comparison to PP2 and RP, respectively. Additionally, PP1 substantially increased P availability in soils with high clay contents 15 days after planting (DAP), showing increases of 61.90%, 99.04%, and 38.09% greater than PP2, RP, and TSP. For Ca and Mg accumulation, the highest values were found in the COxisol2 soil when PP2 was applied, Ca = 44.31% and 69.48%; and Mg = 46.23 and 75.79%, greater than PP1 and RP, respectively. Finally, the highest values for relative agronomic efficiency were observed in COxisol2 when PP1 was applied. The precipitated phosphate sources (PP1 and PP2) exhibited a similar behavior to that of the commercial source (TSP), suggesting their potential use to reduce reliance on TSP fertilization, especially in soils with low clay contents. This study emphasized strategies for soil P management, aimed at assisting farmers in enhancing maize crop productivity while simultaneously addressing the effectiveness of alternative P sources of reduced costs.

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Bacterial inoculants have been used in agriculture to improve plant performance. However, laboratory and field requirements must be completed before a candidate can be employed as an inoculant. Therefore, this study aimed to evaluate the parameters for inoculant formulation and the potential of Bacillus subtilis (B70) and B. pumilus (B32) to improve phosphorus availability in maize (Zea mays L.) crops. In vitro experiments assessed the bacterial ability to solubilize and mineralize phosphate, their adherence to roots, and shelf life in cassava starch (CS), carboxymethyl cellulose (CMC), peat, and activated charcoal (AC) stored at 4 °C and room temperature for 6 months. A field experiment evaluated the effectiveness of strains to increase the P availability to plants growing with rock phosphate (RP) and a mixture of RP and triple superphosphate (TS) and their contribution to improving maize yield and P accumulation in grains. The B70 was outstanding in solubilizing RP and phytate mineralization and more stable in carriers and storage conditions than B32. However, root adherence was more noticeable in B32. Among carriers, AC was the most effective for preserving viable cell counts, closely similar to those of the initial inoculum of both strains. Maize productivity using the mixture RPTS was similar for B70 and B32. The best combination was B70 with RP, which improved the maize yield (6532 kg ha-1) and P accumulation in grains (15.95 kg ha-1). Our results indicated that the inoculant formulation with AC carrier and B70 is a feasible strategy for improving phosphorus mobilization in the soil and maize productivity.

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The researchers of Russian State Agrarian University, Moscow Timiryazev Agricultural Academy in 2013-2016 conducted a long-term stationary experiment to study chemical and toxicological properties of fiber flax, Voskhod variety, growing on sod-podzolic soil in the soil and climate of the Moscow region. Test plots were selected with following crop rotation options: without fertilizers, without liming; without fertilizers, with liming; N100P150K120 (kg a.i./ha), without liming; N100P150K120, with liming; N100P150K120 + manure 20 t/ha, without liming; N100P150K120 + manure 20 t/ha, with liming. The agro-climatic conditions of the growing seasons during the research years did not have a negative impact on the growth and development of fiber flax, the hydro-thermal index was 1.1 in 2013, -1.05 in 2014, 1.5 in 2015, and 1.5 in 2016. The maintained crop rotation and the introduction of a full range of mineral and organic fertilizers has been found to contribute to high yields of flax in terms of fiber (18.5-18.9 hwt/ha) and seeds (7.9-8.3 hwt/ha). The seeds contain 16.9-19.5% protein and 33.5-39.4% lipids. The yield of flaxseed oil from seeds ranged from 19.5-35.7% on average for different variants of the experiment. The peroxide number index was 2.5-1.5 mg-eq O2/kg, the acid number index was 1.1-1.9 mg KOH/g, which corresponds to obtaining high-quality linseed oil in compliance with quality standards for all variants of the experiment.

Os pesquisadores da Universidade Agrária Estatal Russa, Academia Agrícola Timiryazev de Moscou, de 2013 a 2016, realizaram um experimento estacionário de longo prazo para estudar as propriedades químicas e toxicológicas da fibra de linho, variedade Voskhod, crescendo em solo sod-podzólico e no clima da região de Moscou. As parcelas-teste foram selecionadas com as seguintes opções de rotação de culturas: sem fertilizantes e sem calagem; sem fertilizantes e com calagem; N100P150K120 (kg ia/ha), sem calagem; N100P150K120 e com calagem; N100P150K120 + esterco 20 t/ha e sem calagem; N100P150K120 + esterco 20 t/há e com calagem. As condições agroclimáticas das épocas de cultivo durante os anos de pesquisa não tiveram impacto negativo no crescimento e desenvolvimento do linho têxtil, o índice hidrotérmico foi de 1,1 em 2013, -1,05 em 2014, 1,5 em 2015 e 1,5 em 2016. Verificou-se que a manutenção da rotação de culturas e a introdução de uma gama completa de fertilizantes minerais e orgânicos contribuem para altos rendimentos de linho em termos de fibra (18,5-18,9 hwt/ha) e sementes (7,9-8,3 hwt/ha). As sementes contêm 16,9-19,5% de proteína e 33,5-39,4% de lipídios. O rendimento de óleo de linhaça das sementes variou de 19,5 a 35,7% em média para diferentes variantes do experimento. O índice de peróxido foi de 2,5-1,5 mg-eq O2/kg, o índice de acidez foi de 1,1-1,9 mg KOH/g, o que corresponde à obtenção de óleo de linhaça de alta qualidade em conformidade com os padrões de qualidade para todas as variantes do experimento.

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Evaluate the effect of ascorbic acid application and coexistence of Mycorrhiza fungus and Azospirillium on basil (Ocimum basilicum L.) under drought stress. This experiment was performed as a split factorial in a randomized complete block design with three replications in the crop year 2017-2018 in Shahriar, Iran. In this experiment, irrigation was the main factor in three levels, including drought stress based on 40-70-100 mm from the evaporation pan of class A. Biofertilizer including growth-promoting bacteria (Azospirillium) and mycorrhiza fungus in four levels, including a(Non-consumption) B (Seeds of growth-promoting bacteria (Azospirillium)) C (Consumption of mycorrhiza fungus as seeds) D (Concomitant use of growth-promoting bacteria Azospirillium with mycorrhiza fungi as seeds) and ascorbic acid in two levels of foliar application, including A (Absence Application of ascorbic acid) and B (Application of ascorbic acid (two days after irrigation treatment)) was considered as a factorial factor. The results showed that the highest biological yield was obtained in drought stress of 40 mm and application of biological fertilizers in the form of mycorrhiza application with an average of 3307.1 kg/ha, which was about 70% more than 100 mm evaporation stress and no application of biological fertilizer. The use of ascorbic acid under drought stress conditions improved by 10%, the essential oil using ascorbic acid evaporated under drought stress conditions of 100 mm. As a general conclusion, the use of ascorbic acid and Mycorrhiza + Azospirillium biological fertilizer improved the quantitative and qualitative characteristics of basil under drought stress.

Avaliar o efeito da aplicação de ácido ascórbico e coexistência do fungo Mycorrhiza e Azospirillium em manjericão (Ocimum basilicum L.) sob estresse hídrico. Este experimento foi realizado como um fatorial dividido em um delineamento de blocos completos casualizados com três repetições no ano-safra de 2017-2018 em Shahriar, Irã. Neste experimento, a irrigação foi o fator principal em três níveis, incluindo o estresse hídrico baseado em 40-70-100 mm do tanque de evaporação da classe A. Biofertilizante incluindo bactérias promotoras de crescimento (Azospirillium) e fungo Mycorrhiza em quatro níveis, incluindo um (Não consumo), B (Sementes de bactérias promotoras de crescimento (Azospirillium)), C (Consumo de fungos micorrízicos como sementes), D (Uso concomitante de bactérias promotoras de crescimento Azospirillium com fungos micorrízicos como sementes) e ácido ascórbico em dois níveis de foliar aplicação, incluindo A (Ausência de aplicação de ácido ascórbico) e B (Aplicação de ácido ascórbico (dois dias após o tratamento de irrigação)) foi considerado como fator fatorial. Os resultados mostraram que o maior rendimento biológico foi obtido no estresse hídrico de 40 mm e aplicação de fertilizantes biológicos na forma de aplicação de micorrizas com média de 3.307,1 kg/ha, que foi cerca de 70% superior ao estresse evaporativo de 100 mm e sem aplicação de fertilizante biológico. O uso de ácido ascórbico em condições de estresse hídrico melhorou em 10%, o óleo essencial usando ácido ascórbico evaporou em condições de estresse hídrico de 100 mm. Como conclusão geral, o uso de ácido ascórbico e fertilizante biológico Mycorrhiza + Azospirillium melhorou as características quantitativas e qualitativas do manjericão sob estresse hídrico.

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Controlled-release fertilizers have been increasingly used. This study aimed to evaluate and adapt new technologies applied via soil for sustainable coffee production, in order to generate information that contribute to the technical innovation of the crop for the Vale do Ribeira region. The experiment was set at UNESP, in Registro ­ SP. The experimental design was in randomized blocks. The experiment consisted of eight treatments with four replications, with plots of six plants. Four doses (200, 300, 400 and 500 kg ha-1) of a mixed fertilizer 20-05-20 were used, with controlled release in six months, intended for coffee trees in formation and production, compared to the dose of 500 kg ha-1 of the conventional mixed fertilizer 20-05-20, ammonium sulfate and calcium nitrate with boron, in addition to a control treatment, which did not receive NPK fertilization. The cultivar used was 'Obatã IAC 1669' in 3.0 x 0.6 m spacing. The following characteristics were evaluated: number of plagiotropic branches, number of nodes of plagiotropic branches, stem diameter, plant height and yield, in two harvest periods, besides the surface chemical characteristic of the soil. Increasing the dose of the slow-release fertilizer leads to greater plant growth; the coffee plant presents a highly responsive behavior to the increase in fertilizer doses in relation to nitrogen, and the use of the slow-release fertilizer Agroblen (20-05-20) 100% and ammonium sulfate + SS + KCl allows greater yield.

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We aimed to quantify the N losses through volatilization of the main conventional and stabilized N fertilizers applied in coffee plantations. Additionally, we also assessed microbiological attributes of the soil (microbial biomass carbon (MBC); microbial biomass nitrogen (MBN); microbial basal respiration (MBR); metabolic quotient (qCO2); urease, ß-glucosidase, acid phosphatase, and arylsulfatase activities) and agronomic aspects of the crop (N content in the leaves and beans, yield, and N exportation by the beans). Treatments consisted of the combination of three fertilizers (ammonium nitrate - AN, conventional urea - U, and urea with N- (n-butyl) thiophosphoric triamide (NBPT) - UNBPT, and five doses of N (0, 150, 275, 400, and 525 kg ha-1 year-1 of N), with four replicates, totalling 60 experimental plots. In the two crop seasons evaluated, daily and cumulative losses of N-NH3 from the split fertilizer applications were influenced by the N fertilizer technologies. The application of U resulted in losses of 22.0% and 22.8% for the doses of 150 and 400 kg ha-1 year-1 of N. This means that 66 and 182 kg ha-1 of N-NH3 were lost, respectively, at the end of six fertilizations with U. UNBPT reduced urease activity and N-NH3 losses compared to conventional urea, avoiding the volatilization of 15.9 and 24.3 kg ha-1 of N. As for AN, N-NH3 losses did not exceed 1% of the applied dose, regardless of the weather conditions during the fertilization. Urease activity was higher on days of maximum NH3 volatilization. There was an effect of the N sources (NS), soil sampling time (ST), and their interaction (NS × ST) on the MBN and arylsulfatase activity. The N sources also influenced the MBC and the qCO2. A substantial amount of N was removed from the system by the beans and husks of the harvested fruits. Our study showed that N fertilizer technologies are interesting options to reduce N-NH3 losses by volatilization, increase N retention in the soil, and improve microbiological attributes and the sustainability of coffee production systems.

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Humans are constantly exposed to radioactivity present in rocks, soils, and water, mainly from materials in the Earth's crust that contain chemical elements belonging to the radioactive series of uranium and thorium. An important anthropogenic source of these natural radioisotopes to the environment is fertilizers, widely used to increase agricultural productivity. Exposure to ionizing radiation can become a public health problem worldwide, since it is related to the development of different cancers in humans. The present study aimed to survey research on the radioactive content in different types of mineral phosphate fertilizers used around the world through a comprehensive review of the Scopus and Web of Science databases. About 80 scientific articles fit the purpose of this review. The concentration activity values found varied widely from one country to another, and there is no specific legislation that determines the maximum allowed limits of radioisotopes in these agricultural inputs. In addition, there are still uncertainties regarding the impact of natural radioactivity from fertilizers on human health, highlighting the need for further investigations on the subject.

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Mini-roses (Rosa chinensis Jacq.) is largely used in salty dishes and desserts. This study evaluated instrumental color, sugars, organic acids, phenolics, volatiles, and the indigenous microbiota (fungi and bacteria) in edible mini-roses farmed in discarded fruits biocompost and animal manure systems. A descriptive sensory analysis of flowers was also performed. Mini-roses farmed in biocompost had higher luminosity and intensity of instrumental red color, a higher concentration of phenolic compounds, including anthocyanins related to red color, and fructose than mini-roses farmed in animal manure (p < 0.05). Furthermore, mini-roses farmed in biocompost had higher concentrations of various volatiles (p < 0.05), including hexyl acetate and cis-3 -hexenyl butyrate related to the fruity aroma. Bacterial groups related to plant growth-promoting such as Stenotrophomonas and endophilic fungal groups such as Eurotiales sp, Pleosporales sp were found in higher abundance (p < 0.05) in mini-roses farmed in biocompost. Mini-rose farmed in biocompost also received higher score (p < 0.05) for fruity aroma and red color than mini-rose mini-roses farmed in animal manure. Results indicate that farming mini-roses using biocompost from discarded fruits impacts the synthesis of phenolics and volatiles, resulting in a more intense fruity aroma and red color. Findings also suggest that the microbiota of mini-roses farmed in biocompost or animal manure do not represent a major risk for the safety of these products.

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Agriculture will face the issue of ensuring food security for a growing global population without compromising environmental security as demand for the world's food systems increases in the next decades. To provide enough food and reduce the harmful effects of chemical fertilization and improper disposal or reusing of agricultural wastes on the environment, will be required to apply current technologies in agroecosystems. Combining biotechnology and nanotechnology has the potential to transform agricultural practices and offer answers to both immediate and long-term issues. This review study seeks to identify, categorize, and characterize the so-called smart fertilizers as the future frontier of sustainable agriculture. The conventional fertilizer and smart fertilizers in general are covered in the first section of this review. Another key barrier preventing the widespread use of smart fertilizers in agriculture is the high cost of materials. Nevertheless, smart fertilizers are widely represented on the world market and are actively used in farms that have already switched to sustainable technologies. The advantages and disadvantages of various raw materials used to create smart fertilizers, with a focus on inorganic and organic materials, synthetic and natural polymers, along with their physical and chemical preparation processes, are contrasted in the following sections. The rate and the mechanism of release are covered. The purpose of this study is to provide a deep understanding of the advancements in smart fertilizers during the last ten years. Trends are also recognized and studied to provide insight for upcoming agricultural research projects.

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The problem of phosphorus and nitrogen deficiency in agricultural soils has been solved by adding chemical fertilizers. However, their excessive use and their accumulation have only contributed to environmental contamination. Given the high content of nutrients in biosolids collected from a food industry waste treatment plant, their use as fertilizers was investigated in Zea mays plants grown in sandy loam soil collected from a semi-desert area. These biosolids contained insoluble phosphorus sources; therefore, given the ability of Azotobacter nigricans to solubilize phosphates, this strain was incorporated into the study. In vitro, the suitable conditions for the growth of Z. mays plants were determined by using biosolids as a fertilizer and A. nigricans as a plant-growth-promoting microorganism; in vitro, the ability of A. nigricans to solubilize phosphates, fix nitrogen, and produce indole acetic acid, a phytohormone that promotes root formation, was also evaluated. At the greenhouse stage, the Z. mays plants fertilized with biosolids at concentrations of 15 and 20% (v/w) and inoculated with A. nigricans favored the development of bending strength plants, which was observed on the increased stem diameter (>13.5% compared with the negative control and >7.4% compared with the positive control), as well as a better absorption of phosphorus and nitrogen, the concentration of which increased up to 62.8% when compared with that in the control treatments. The interactions between plants and A. nigricans were observed via scanning electron microscopy. The application of biosolids and A. nigricans in Z. mays plants grown in greenhouses presented better development than when Z. mays plants were treated with a chemical fertilizer. The enhanced plant growth was attributed to the increase in root surface area.

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Composted sewage sludge (CSS) is an organic fertilizer that can be used as a source of micronutrients in agriculture. However, there are few studies with CSS to supply micronutrients for the bean crop. We aimed to evaluate micronutrient concentrations in the soil and their effects on nutrition, extraction, export, and grain yield in response to CSS residual application. The experiment was carried out in the field at Selvíria-MS, Brazil. The common bean cv. BRS Estilo was cultivated in two agricultural years (2017/18 and 2018/19). The experiment was designed in randomized blocks with four replications. Six different treatments were compared: (i) four increasing CSS rates, i.e., CSS5.0 (5.0 t ha-1 of applied CSS, wet basis), CSS7.5, CSS10.0, CSS12.5; (ii) a conventional mineral fertilizer (CF); (iii) a control (CT) without CSS and CF application. The available levels of B, Cu, Fe, Mn, and Zn were evaluated in soil samples collected in the 0-0.2 and 0.2-0.4 m soil surface horizons. The concentration, extraction, and export of micronutrients in the leaf and productivity of common beans were evaluated. The concentration of Cu, Fe, and Mn ranged from medium to high in soil. The available levels of B and Zn in the soil increased with the residual rates of CSS, which were statistically not different from the treatments with CF. The nutritional status of the common bean remained adequate. The common bean showed a higher requirement for micronutrients in the second year. The leaf concentration of B and Zn increased in the CSS7.5 and CSS10.0 treatments. There was a greater extraction of micronutrients in the second year. Productivity was not influenced by the treatments; however, it was higher than the Brazilian national average. Micronutrients exported to grains varied between growing years but were not influenced by treatments. We conclude that CSS can be used as an alternative source of micronutrients for common beans grown in winter.

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En Perú, al 2019, solo el 6,4 % de los distritos disponen sus residuos urbanos en rellenos sanitarios, los cuales, están en situación de colapso, lo que exige buscar alternativas para mejorar la gestión de estos residuos y, frente a ello, el compostaje se perfila como una tecnología simple y económica, empleada para el tratamiento del componente orgánico, para reducir daños a la salud y al ambiente, sin embargo, la falta de criterios técnicos en su aplicación está afectando la calidad del compost final. El objetivo de esta investigación fue evaluar los criterios técnicos de procesamiento y la calidad del compost, a través de residuos sólidos urbanos en los distritos de la provincia Leoncio Prado. La investigación identificó los distritos que aplican el compostaje a sus residuos y evaluó la técnica de procesamiento, indicadores fisicoquímicos y determinó la calidad con base en normas técnicas internacionales. Los resultados muestran que seis de diez distritos aplican el compostaje y los indicadores fisicoquímicos contrastados con los criterios de calidad de la norma técnica chilena (NCH 2880), colombiana 5167 y de la OMS, corresponden a compost de calidad intermedia (Clase B). Los compost evaluados no representan riesgo ambiental y pueden ser utilizados como enmienda en la mejora del suelo y los cultivos con algunas restricciones, por presentar valores elevados de humedad, pH y bajos niveles de P, Ca, Mg y K.

At 2019, in Peru, only 6.4 % of the districts dispose of their urban waste in sanitary landfills, which are in a situation of collapse, therefore is needed looking for alternatives to improve the management of this waste, facing this, composting is emerging as a simple and economical technology used for the treatment of the organic component, thus, reducing damage to health and the environment, however, the lack of technical criteria in its application is affecting the quality of the final compost. The objective of this research was to evaluate the technical criteria for processing and the quality of compost based on municipal solid waste in the districts of Leoncio Prado province. The research identified the districts that apply composting to their waste and evaluated the processing technique, physicochemical indicators and determined the quality based on international technical standards. The results show that six out of ten districts apply composting, and the physicochemical indicators contrasted with the quality criteria of the Chilean technical standard (NCH 2880), Colombian 5167 and WHO, correspond to intermediate quality compost (Class B). The evaluated compost does not represent an environmental risk and can be used as an amendment in soil and crop improvement with some restrictions, since it has high moisture, pH and low levels of P, Ca, Mg and K.

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Correct waste disposal from the agro-industrial sector represents one of the premises for sustainable agriculture. This work aimed to analyze the use of sugarcane filter cake in soybean fertilization and its effects on soil chemical attributes. The experiment was conducted in a randomized block design with 6 treatments and 4 replications: T1 - Control; T2 - Mineral fertilization (300 kg ha-1 of the formulated 00-30-10); and the following percentages of the recommended dose of filter cake: T3 - 50% (17 ton ha-1), T4 - 100% (34 ton ha-1), T5 - 150% (51 ton ha-1), and T6 - 200% (68 ton ha-1). The soil chemical attributes were evaluated, and soybean was assessed for germination, number of pods per plant, number of seeds per pod, plant height, height of the first pod insertion, and yield. The treatments promoted no differences in soybean germination or height of the first pod insertion, while the use of filter cake positively influenced plant height. Moreover, no differences among treatments were found for pods per plant, seeds per pod, thousand-seed weight, and yield. Therefore, using organic filter cake residue in soybean cultivation is feasible, representing an alternative to chemical fertilization for soybean cultivation.(AU)

A destinação correta de resíduos do setor agroindustrial é uma das premissas para agricultura sustentável. O objetivo do trabalho foi analisar a utilização de torta de filtro, resíduo da indústria sucroalcooleira, na adubação da soja e seus efeitos sobre os atributos químicos do solo. A unidade experimental foi delineada em blocos casualizados com 6 tratamentos e 4 repetições: T1 ­ Testemunha; T2 ­ Adubação mineral (300 kg ha-1 do formulado 00-30-10); T3 ­ 50% da dose recomendada de torta de filtro (17 ton ha-1); T4 ­ 100% da dose recomendada de torta de filtro (34 ton ha-1); T5 ­ 150% da dose recomendada de torta de filtro (51 ton ha-1); T6 ­ 200% da dose recomendada de torta de filtro (61 ton ha-1). Foram avaliados os atributos químicos do solo e na cultura da soja a germinação, produtividade, número de vagens por planta, número de sementes por vagem, altura de plantas e a inserção da primeira vagem. Os tratamentos não promoveram diferenças na germinação da soja. Para a altura das plantas, o uso da torta de filtro influenciou de forma positiva. A altura da inserção da primeira vagem não apresentou diferenças entre os tratamentos. Para os parâmetros vagens por planta, sementes por vagem, peso de mil sementes e produtividade não houve diferenças entre os tratamentos. Para os atributos químicos do solo, foram observadas diferenças para os teores de matéria orgânica e carbono. O emprego do resíduo orgânico torta de filtro na cultura da soja é viável, pois apresentou-se como uma alternativa para adubação química na cultura da soja.(AU)

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Since soybean is widely cultivated around the world and has a high protein content, it is a great nutritional vehicle for increasing the dietary uptake of selenium (Se). Several studies have evaluated biofortification with Se through fertilizer application in several crops. However, it is not clear how each method and source affect the total Se content or Se species in soybean grains. This work aimed to assess the total Se content and Se speciation in Se-enriched soybean grains produced under different Se application methods in the field. The treatments consisted of Se application (soil or foliar), using organic or inorganic Se sources at 10 g ha-1 or 80 g ha-1, in two genotypes. The results showed that all treatments with inorganic Se (soil and foliar) increased the Se content in grains compared with the control. More than 80% of the total Se in grains was present as selenomethionine (SeMet), and the speciation was affected by the Se source and the method of application. The treatments using inorganic Se, applied via soil or foliar, produced the highest content of Se as SeMet in soybean grains. Finally, we propose that the preservation of the Se species in products derived from soybean grains be evaluated as the following step.

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The present study had the objective to evaluate the effect of blends of KCl and K2SO4 fertilizers and their influence on the yield and the nutritional state of coffee plants, as well as on the chemical composition and quality of the coffee beverage. The experimental design was in randomized blocks with four repetitions and six treatments (T1: 100% KCl; T2: 75% KCl + 25% K2SO4; T3: 50% KCl + 50% K2SO4; T4: 25% KCl + 75% K2SO4; T5: 100% K2SO4; and a control, without application of K). The following analyses were performed: K and Cl content in the leaves and the soil, stocks of Cl in soil, yield, removal of K and Cl with the beans, cup quality of the beverage, polyphenol oxidase activity (PPO), electric conductivity (EC), potassium leaching (KL), the content of phenolic compounds, the content of total sugars (TS), and total titratable acidity (TTA). The stocks of Cl in the soil decreased as the proportion of KCl in the fertilizer was reduced. The fertilization with KCl reduces the cup quality and the activity of the polyphenol oxidase, probably due to the ion Cl. The increase in the application of Cl directly relates to the increase in potassium leaching, electric conductivity, and titratable acidity. Indirectly, these variables indicate damages to the cells by the use of Cl in the fertilizer. The activity of the polyphenol oxidase enzyme and the cup quality indicate that the ion Cl- reduces the quality of the coffee beverage. K content in the leaves was not influenced by the application of blends of K fertilizer while Cl content increased linearly with KCl applied. The application of KCl and K2SO4 blends influenced coffee yield and the optimum proportion was 25% of KCl and 75% of K2SO4. The highest score in the cup quality test was observed with 100% K2SO4.

RESUMO

Livestock waste is widely used in agriculture. Although they provide benefits to the soil, and consequently to plants, they have the potential to contaminate the environment, as they contain pathogenic microorganisms and determinants of antimicrobial resistance, if not properly managed. Therefore, this study aims to evaluate the effect of composting horse bedding and poultry litter in organic and conventional production systems on the occurrence of bacteria in the Enterobacteriales order and to identify their antimicrobial resistance profiles. Bacterial strains were isolated from Salmonella-Shigella and eosin methylene blue solid media from animal waste during the composting process that was conducted for 125 days. After isolation, the strains were identified by the MALDI-TOF technique; the disk diffusion test was then performed for phenotypic detection of antimicrobial resistance. A total of 158 bacterial strains were isolated during composting of three wastes. The Enterobacteriaceae family was the most abundant, whereas Proteus mirabilis and Escherichia coli were the species with the highest percentage in the wastes, which also exhibited a multi-resistance profile. Poultry litter showed a greater abundance of resistant bacteria than horse bedding did. Similarly, a greater number of resistant bacteria was detected in conventional poultry litter than in organic poultry litter. The results obtained reinforce that animal wastes are reservoirs of pathogenic bacteria that are resistant to antimicrobials and highlight the importance of developing management strategies that aim to reduce and/or eliminate these contaminants to guarantee their safe use in agriculture.

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RESUMO

Chelates are nutrient-rich compounds that enhance the condition of plant tissues as micronutrients. Micronutrient deficiencies particularly iron (Fe) and zinc (Zn) leads to various problems for plant including chlorosis and necrosis etc. An adequate intake of Fe and Zn etc. is required by the human body. Biofortification of cereals with Fe and Zn is seen as a cost-effective solution to the problem of Fe and Zn deficiencies as well. In recent decades, many chelating compounds have been established and incorporated into agricultural systems. The most recent formulation involves the use of amino acids synthesized with one or more nutrient ions to improve fertilizer efficiency and better respond to environmental conservation. In addition to its primary function as a source of micronutrients, aminochelled are an active nitrogen (N) stimulant in plant nutrition, preventing the negative effects of basic N fertilizers like urea. The use of amino chelates, rather than just chemical fertilizers, has been shown to provide better production and quality as well as higher nutritional concentrations in several experiments. Furthermore, this review sheds light on various aspects of amino chelates fertilizers including types, history, and their effects on agricultural crops. In spite of amino chelates fast dominance in many countries' fertilizer countries, there is not enough scientific data and knowledge on the specific reactions of plants to biotic and abiotic stresses from amino fertilizers.

Os quelatos são compostos ricos em nutrientes que melhoram a condição dos tecidos vegetais como micronutrientes. Deficiências de micronutrientes, particularmente ferro (Fe) e zinco (Zn), levam a vários problemas para as plantas, incluindo clorose e necrose, etc. A ingestão de uma quantidade adequada de Fe e Zn, etc., é exigida pelo corpo humano. A biofortificação de cereais com Fe e Zn também é vista como uma solução econômica para o problema das deficiências de Fe e Zn. Nas últimas décadas, muitos compostos quelantes foram estabelecidos e incorporados em sistemas agrícolas. A formulação mais recente envolve o uso de aminoácidos sintetizados com um ou mais íons nutrientes para melhorar a eficiência do fertilizante e responder melhor à conservação ambiental. Além de sua função primária como fonte de micronutrientes, os aminoquelados são um estimulante de nitrogênio (N) ativo na nutrição das plantas, evitando os efeitos negativos de fertilizantes nitrogenados básicos como a ureia. O uso de aminoquelatos, ao invés de apenas fertilizantes químicos, tem mostrado proporcionar melhor produção e qualidade, bem como maiores concentrações nutricionais em vários experimentos. Além disso, a presente revisão lança luz sobre vários aspectos dos fertilizantes aminoquelatos, incluindo tipos, história e seus efeitos nas culturas agrícolas. Apesar do domínio rápido dos aminoquelatos em muitos países de fertilizantes, não há dados científicos suficientes e conhecimento sobre as reações específicas das plantas aos estresses bióticos e abióticos dos fertilizantes amino.

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