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Made available in DSpace on 2020-12-12T02:04:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-15 Sewage sludge (SS) is widely used in agriculture in several countries around the world. However, the impact of successive applications of SS on soil and the risks of nutrient leaching are often neglected. In this study, corn was grown on a constructed wetland for four crop cycles (two years), in which the wetland was subjected to successive SS applications. The objective of this study was to evaluate how the successive applications of SS affect the availability and leaching of nutrients in the soil profile, after two years of cultivation. Experiments were performed using a randomized block design with repeated measurements in time, that is, soil was sampled in each harvest. Six treatments were tested: four fertilizations based on sewage sludge, resulting from biological and anaerobic treatment, calculated to provide 25 (SS25), 50 (SS50), 75 (SS75), and 100% (SS100), of the N required for corn production (140 kg ha−1); a mineral fertilization (NPK) (140 kg ha−1 N, 70 kg ha−1 of P2O5 and 40 kg ha−1 of K2O) and a control (without fertilization). The results showed that four consecutive applications of SS100 for two years caused significant accumulation of nutrients and organic matter in the superficial layers of the soil. The electrical conductivity and the concentration of NO3 – in the soil solution were higher than those permitted by Brazilian legislation. The adoption of domestic SS in Brazilian agriculture can be a viable alternative in the search for an environment-friendly and economically feasible method for SS disposal. Instituto de Ciências Agrárias e Ambientais Universidade Federal de Mato Grosso (UFMT) Department of Soil Science Luiz de Queiroz College of Agriculture University of São Paulo Piraciaba Department of Plant Health Rural Engineering and Soils São Paulo State University “Julio de Mesquita Filho” Ilha Solteira Departamento de Zootecnia e Extensão Rural Universidade Federal de Mato Grosso (UFMT) Department of Agricultural Engineering Maringá State University Cidade Gaúcha Departamento Gestão do Agronegócio Universidade Paulista (UNIP) São Paulo UNESP - São Paulo State University Department of Forest Soil and Environmental Sciences College of Agricultural Sciences Department of Plant Health Rural Engineering and Soils São Paulo State University “Julio de Mesquita Filho” Ilha Solteira UNESP - São Paulo State University Department of Forest Soil and Environmental Sciences College of Agricultural Sciences

Sulfadiazine (SDZ) residues have been detected in manured soils as well as their adjacent water resources, but its behavior is still poorly understood in acidic tropical soils. This research aimed to evaluate sorption, leaching, and biodegradation of 14C-SDZ in four acidic soils from Brazil, using OECD guidelines. Except for the sand soil (Kd = 2.6 L kg−1), SDZ sorption tended to be higher (Kd > 8.4 L kg−1) and more hysteretic (ΔH >> 1) in acidic soils. When freshly applied, SDZ leaching was low ( 78% of AR up to 7 days). For certain acidic soils, the abrupt breakdown of the SDZ suggests that degradation should be initially chemical and then followed by enzymatically driven reactions. The fast formation of NERs was attributed mostly to chemical bounding to soil humic substances (Type II-NER), but SDZ sequestration cannot be ruled out (Type I-NER). NERs represent a long-term environmental reservoir of SDZ that may cause deleterious effects on non-target organisms as well as promote antibiotic resistance to soil microbes.

Few aquatic plants can accumulate As from flooded soils. Given the high toxicity and bioavailability of As in these environments, a study was carried out in Brazil to test the As phytoextraction potential of Typha domingensis and Eleocharis acutangula, comprising three cutting/regrowth cycles of 120 days each. The species were grown in uncontaminated (control), moderately contaminated (75 mg kg−1 As), and highly contaminated (250 mg kg−1 As) soil. The amount of As extracted was influenced by the level of As contamination and the plant species. E. acutangula was the most suitable species for removing As from moderately contaminated soil (up to 75 mg kg−1), while T. domingensis could remove As from soil with As levels up to 250 mg kg−1. This small-scale study provides a theoretical basis for the selection of macrophytes with potential for As extraction from soils, and these species should be tested in the future under field conditions.

In anoxic environmental conditions and with a drastic reduction of the redox potential, the barium sulphate used in petroleum drilling fluids becomes a hazard to the ecosystem. A field study was conducted in Brazil in an area with a history of accidental Barium (Ba) contamination to evaluate the role of frequent plant cutting on phytoremediation. The plant species Typha domingensis and Eleocharis acutangula, cultivated in a combined plantation, were subjected to four different cut frequencies: every 90 days (four cuts), 120 days (three cuts), 180 days (two cuts), or 360 days (one cut). The total amount of Ba extracted from the soil by the plants was evaluated for each treatment and at different soil depths Overall, total Ba in the soil decreased the most dramatically for cut frequencies of 120 (37.83%) and 180 (47.73%) days at 0–0.2 m below the surface, and with cut frequencies of 120 (51.98%) and 360 (31.79%) at 0.2–0.4 m depth. Further, total Ba in the plant biomass was greatest in the 120 and 360-days frequency groups. Thus, cuts at intervals of 120 days or more are associated with high levels of Ba in the plant tissue and a decrease of soil Ba.

Aquatic macrophytes are potentially useful for phytoremediation on flooded areas. A field study in Brazil was conducted to evaluate Eleocharis acutangula (E), Cyperus papyrus (C) and Typha domingensis (T) in monocropping and intercropping, aiming to phytoremediate barium-polluted flooded soils. The treatments were: monocroppings (E, C and T); double intercroppings (EC, ET and CT); and triple intercropping (ECT). The 180-d field trial was performed in a flooded area with high barium content, with a randomized complete block design and three replicates. Plant stand size, biomass yield, and Ba concentration aboveground/Ba concentration in roots (translocation factor – TF) as well as Ba mass aboveground/Ba mass in roots (mass translocation factor – mTF) were determined. Most of the treatments did not differ on dry biomass, except for EC, which showed the lowest yield. Consistently with its biology, E. acutangula in monocropping showed the largest plant stand. Otherwise, intercroppings with T. domingensis achieved the highest amounts of barium absorbed from the soil and transferred most of the barium content from belowground to aboveground (mTF > 1.0), especially ET, which showed the highest mTF among the intercroppings (2.03). Remarkably, TF values did not reflect such phytoextraction ability for CT and ECT. Thus, mTF was more appropriate than TF to assess phytoextraction capacity. Furthermore, it was demonstrated that intercropping can increase barium uptake from flooded soils. Particularly, the intercropping ET constituted the most cost-effective treatment, with the cyperaceous species providing high plant coverage while T. domingensis facilitated barium removal by translocating it to the aboveground biomass.

The management of initial planting density can be a strategy to increase barium phytoextraction from soil, reducing the time required for soil decontamination. To delimit the ideal planting density for barium (Ba) phytoremediation using Typha domingensis, we conducted a 300-day experiment in an area accidentally contaminated with barite. Four initial planting densities were tested: 4, 8, 12, and 16 plants m−2 (D4, D8, D12, and D16 treatments, respectively). Plant development was evaluated periodically, and the phytoextraction efficiency was determined at the end of the trial. The initial planting density affected Ba phytoremediation by T. domingensis monoculture. Phytoextraction potential was better represented by the mass-based translocation factor (mTF) than the concentration-based translocation factor. D16 promoted the highest final number of plants and biomass production, but the mass of Ba in the aerial part did not differ among D8, D12, and D16. D4 resulted in more Ba accumulated belowground than aboveground (6.3 times higher), whereas D12 and D16 achieved the greatest mTFs. Higher absorption of Ba from soil can be achieved using less T. domingensis individuals at the beginning of the treatment (D4 and D8) but with high accumulation in belowground tissues. We conclude that the D8 density is considered the most appropriate if considering the phytoextraction potential and field management facilitated using fewer plants.

The use of barite (BaSO4) in drilling fluids for oil and gas activities makes barium a potential contaminant in case of spills onto flooded soils, where low redox conditions may increase barium sulfate solubility. In order to select plants able to remove barium in such scenarios, the following species were evaluated on barium phytoextraction capacity: Brachiaria arrecta, Cyperus papyrus, Eleocharis acutangula, E. interstincta, Nephrolepsis cf. rivularis, Oryza sativa IRGA 424, O. sativa BRS Tropical, Paspalum conspersum, and Typha domingensis. Plants were grown in pots and exposed to six barium concentrations: 0, 2.5, 5.0, 10.0, 30.0, and 65.0 mg kg−1. To simulate flooding conditions, each pot was kept with a thin water film over the soil surface (∼1.0 cm). Plants were evaluated for biomass yield and barium removal. The highest amount of barium was observed in T. domingensis biomass, followed by C. papyrus. However, the latter exported most of the barium to the aerial part of the plant, especially at higher BaCl2 doses, while the former accumulated barium preferentially in the roots. Thus, barium removal with C. papyrus could be achieved by simply harvesting aerial biomass. The high amounts of barium in T. domingensis and C. papyrus resulted from the combination of high barium concentration in plant tissues with high biomass production. These results make T. domingensis and C. papyrus potential candidates for phytoremediation schemes to remove barium from flooded soils.

The use of organomineral fertilizers (OMFs) has grown worldwide, mainly in tropical conditions, combining economics and environmental management. Our study used a sewage sludge (SS) rich in Zn as the organic matrix in the manufacture of OMFs, with the following objectives: i) to select the best OMF physical form; ii) to evaluate environmental risks associated with their application; iii) to recycle SS nutrients for soybean (Glycine max) production; iv) to verify their benefits to soil microbial activity and other soil functions. For each soil individually, a clay and a sandy clay loam, six treatments were tested: control (CT, without fertilization); mineral fertilization (MF); MF plus Zn and B (MFZn + B); and three distinct physical forms for the OMFs [powder (Pw), granule (G), and pellet (Pt)], all calculated to provide 100 kg of P2O5 and performed in four blocks. Amending SS-OMFs did not represent an environmental risk in terms of spreading pathogens and hazardous trace elements. In comparison with MFs, SS-OMFs enhanced nutrients accumulation, pod numbers, and nodulation, as well as soil microbial activity, but did not affect shoot and root dry masses and enzymatic activities at early stages of soybean development (60 d after planting). They were also capable to supply Zn and B to plants and their distinct physical forms did not affect microbiological indicators of soil quality or nutrients accumulation in plant tissues. Overall, SS-OMFs seems to be a promising alternative for sustainable use of SSs in soybeans avoiding their disposal in landfills, but field studies are still needed to ratify the findings under more realistic conditions.

The objective of this study was to evaluate the effects of pig slurry (PS) and chemical fertilizer (NPK 02–20–20) applications on soil water infiltration; sediment, water and nutrient losses by runoff; and soybean yield during a soybean (Glycine max L.) cropping cycle. A field study was carried out in Rio Verde, Goias, Brazil on a Cerrado Oxisol managed with no tillage. The experiment was arranged as a randomized block design with three replications and treatments. The treatments consisted of two doses of PS, 25 and 100 m3 ha− 1, and chemical fertilization at 370 kg ha− 1 (NPK 02–20–20) applied to the soil surface in a single application. After the occurrence of rainfall events, the volume of percolated water in lysimeters and the sediment and water losses in plots was measured. To determine the macro and- (Ca, Mg, K, P) micronutrients (Fe, Mn, Cu, Zn), runoff water was collected. We also assessed the dry biomass and productivity of soybean production at the end of the experiment. Treatment with 25 m3 ha− 1 of PS resulted in higher amounts of (106 mm) percolated water in the soil (p > 0.05). Neither losses of water, sediment and nutrients or biomass production and soybean productivity were significantly affected by the PS treatments compared with chemical (NPK) fertilization (p > 0.05). A trend of higher sediment and water losses was observed in the 25 m3 ha− 1 PS treatment (249.86 kg ha− 1 and 20.58 mm, respectively) compared with the 100 m3 ha− 1 PS and chemical (NPK) treatments; the 25 m3 ha− 1 PS treatment showed ~ 10% and ~ 43% higher values of sediment losses, respectively, and ~ 43% and ~ 23% higher values of water losses, respectively. Regarding soybean productivity, the 25 m3 ha− 1 PS treatment showed a tendency of low productivity (3405 kg ha− 1) that was ~ 15% and ~ 20% lower than that of the 100 m3 ha− 1 PS and chemical (NPK) treatments, respectively. The low values of sediment and water required per kilogram of soybean produced in the chemical fertilization and 100 m3 ha− 1 PS treatments indicate that these management regimes are more sustainable.

Barite (BaSO4) is a component of drilling fluids used in the oil and gas industry and may cause barium (Ba) contamination if it is spilled onto flooded soils. Under anoxic soil conditions and low redox potential, sulfate can be reduced to a more soluble form (sulfide), and Ba can be made available. To design a solution for such environmental issues, a field study was conducted in a Ba-contaminated flooded area in Brazil, in which we induced Ba phytoextraction from the management of the planting density of two intercropped macrophytes. Typha domingensis and Eleocharis acutangula were grown in four initial planting densities: “Ld” (low density: 4 and 32 plants m−2); “Md” (medium density: 8 and 64 plants m−2); “Hd” (high density: 12 and 128 plants m−2); “Vhd” (very high density: 16 and 256 plants m−2). Vhd produced the largest number of plants after 300 days. However, the treatments did not differ in terms of the amount of biomass. The increments in the initial planting density did not increase the Ba concentration in the aerial part. The greatest Ba phytoextraction (aerial part + root) was achieved by Ld treatment, which removed approximately 3 kg of Ba ha−1. Md and Vhd treatments had the highest Ba translocation factors. Because more plants per area did not result in greater Ba phytoextraction, a lower planting density was recommended for the intercropping of T. domingensis and E. acutangula to promote the phytoextraction of barium, due to possible lower implementation costs in contaminated flooded environments.

Sao Paulo is the most populous and industrialized state of Brazil, which strongly affect amounts and composition of the generated sewage sludges. Their use on agriculture sounds the most feasible disposal strategy since most Brazilian soils have low fertility, but the levels of hazardous substances must be low. This research examined the impacts of sewage source [domestic or mixed (domestic + industrial)] and sewage processing (liming and redox conditions) on the chemical attributes of sludges from 19 wastewater treatment plants of Sao Paulo; as well as their suitability for agricultural use. Sewage source and liming were the main factors affecting sludges’ chemical attributes, while redox conditions played a secondary role. Aerobically treated domestic sewage (C1) generated sludges most suitable for agriculture. Heavy liming in the processing of sewage of mixed origin (C2) produced sludges of much higher pH and Ca, with higher levels of certain hazardous elements (Fe, Zn, Mn, and Cr), but lower levels of OC, N-Kj, and K. Sludges from mixed sewers, not limed (C3) tended to have higher levels of S and hazardous elements (Ba, Mo, Cd, Pb, Ni, Al, and Cu). The inadequately regulated discharge of industrial wastewater into the municipal sewage network accounted for higher levels of hazardous elements in the sludges, but all of them are still suitable for agricultural use since only four sludges showed levels of either Zn (3) or Ni (1) that exceeded the thresholds permitted for direct application to agricultural fields, but both are nutrients to plants and Brazilian soils are often depleted on them. As raw materials for the manufacture of organic fertilizers, the levels of Cd, Cr, or Ni were unacceptable in about half (9) of the samples. It should be revised since hazardous element contents are diluted in the manufacture of the “new compound” and their application rates should be much lower than when sludge is directly applied. In conclusion, “low quality” sludges, such as C2 and mainly C3, have to be either composted or biodigested into “high quality” stabilized sludges; or used in the manufacture of organomineral fertilizers; or treated to remove pathogens and hazardous substances to be amended to agricultural soils, thus avoiding their non-sustainable disposal in landfills.

Macrophytes are widely used in water treatment and have potential for remediation of flooded soils. Many techniques have been proposed to increase the phytoextraction of metals by macrophytes, however, the knowledge of periods of maximum absorption and translocation is essential and is a gap in the management of phytoremediation. To evaluate the absorption and translocation of Ba over time by Eleocharis acutangula, a greenhouse experiment was conducted and the dry matter production of plants, Ba content in the roots and aerial parts, mass of Ba accumulated in plants, translocation factors and removal coefficients of Ba, and Ba content in two layers of the soil (0.0–0.1 m and 0.1–0.2 m) were determined. The highest translocation rates were observed after 105 days of cultivation, when the plants reached a state of hyperaccumulation. The maximum accumulation of barium occurred in the aerial parts of the plants at 105 days and in the roots at both 120 and 180 days. The barium content was reduced up to 120 days, as a result of an increase in available barium content in the soil layer of 0.0–0.1 m up to 105 days and in the layer 0.10–0.20 m up to 120 days, favoring the intense accumulation of Ba during this period. After 120 days of cultivation, the accumulation in the roots maintained a high coefficient of removal of Ba from the soil to the plant. After 180 days the available barium in the soil was depleted due to this high rate of removal by the roots.

A mensuração da área foliar é requerida em vários estudos agronômicos por ser uma das principais medidas para avaliar o crescimento das plantas. Nesse sentido, objetivou-se com o presente trabalho determinar os modelos estatísticos que melhor descrevem a área foliar de macadâmia (Macadamia integrifolia) cv. HAES 344, a partir de dimensões lineares de comprimento e largura do limbo. Um experimento foi realizado em delineamento inteiramente casualizado, em esquema de parcelas subdivididas, com cinco repetições. A parcelaconsistiu dos pontos cardeais (norte, sul, leste e oeste) de uma planta, e as subparcelas foram as três posições na planta (terços inferior, médio e superior). A área foliar foi medida com o auxílio do software ImageJ®, de domínio público, por análise de imagens digitalizadas das folhas. Foram estimadas equações por meio de modelos de regressão linear e não linear, a partir de 600 folhas. As equações obtidas, juntamente com outras quatro equações citadas na literatura para outras cultivares, foram validadas a partir de amostra de 200 folhas. A modelagem estatística de área foliar de plantas adultas de macadâmia - cv. HAES 344 pode ser feita com uso de folhas amostradas de quaisquer dos quatro pontos cardeais e posições de altura nas plantas. A determinação da área foliar é representada com uso do produto do comprimento (C) pela máxima largura (L) das folhas como variável independente. A equação de determinação de área foliar indicada para folhas de plantas adultas de macadâmia - cv. HAES 344 é Ŷi = 1,6635+0,6968 LC.

Objetivou-se avaliar a influência da espessura e integridade de coberturas plásticas na germinação de sementes de repolho (Brassica oleracea var. capitata) cultivadas principalmente na região serrana do Espírito Santo. O experimento foi conduzido no Laboratório de Tecnologia de Sementes no Campus São Mateus da Universidade Federal do Espírito Santo (UFES), em esquema fatorial 2 x 2, com quatro repetições em delineamento inteiramente casualizado. Os tratamentos consistiram de duas espessuras de cobertura dos recipientes (0,06 mm - plástico fino; 0,10 mm - plástico grosso) e a ausência ou presença de furos centralizados na secção superior dos recipientes. As contagens foram feitas do primeiro ao sétimo dia, sendo avaliados os seguintes parâmetros: porcentagem de germinação, índice de velocidade de germinação, tempo médio de germinação, coeficiente de velocidade de germinação e perda de água diária. Verificou-se que não há influência significativa da integridade da cobertura plástica sobre a germinação e é preferível o uso de coberturas plásticas com menor espessura de modo a possibilitar as trocas gasosas.

Organic matter exerts an influence on the chemical, physical, and biological properties of soil. It can also influence the rates of herbicide degradation and sorption into it. This study aimed at evaluating the effect of adding organic compounds to soil over the remediation ability of the plant species Canavalia ensiformis (L.) (jack bean) in sulfentrazone-contaminated soil. The study was conducted in two phases. In the first phase, treatments consisted in a combination of four concentrations of organic compounds and in the application or not of sulfentrazone herbicide. After soil preparation, the herbicide was applied on the surface. Subsequently, seeds of the remediating plant species C. ensiformis were sown. At 75 days after emergence (DAE), samples of the aerial portions and roots of plants and soil were collected. All the collected material was frozen at approximately -20°C and then the accumulation of the herbicide on plants and soil was determined by chromatography. In the second phase, Pennisetum glaucum (L.) (pearl millet) was sown. This species is used as an indicator of sulfentrazone residue in the soil; biometric assessments were performed at 30 and 60 DAE. No sulfentrazone residue was found in the aerial portions or roots of the evaluated remediating plant species; however, it was detected in the soil. The increase in organic compound levels contributed to the growth and accumulation of biomass in pearl millet, when grown after the remediating plant species C. ensiformis , although it did not help phytoremediation.