ABSTRACT Water deficit is a current problem of global relevance. This is a problem in Brazil, especially in the Semiarid region, which undergoes severe droughts for much of the year. This requires the search for alternatives, such as the planned wastewater use, which is a successful alternative in developed countries that is applied for various purposes, including agriculture. However, despite the increasing growth of agriculture in Brazil, there are no established control and monitoring policies to minimize its impacts on the environment and human health. The country does not have specific legislation that defines wastewater quality parameters for domestic sewage. The objective of this work was to compile international guidelines and legislations that address this issue and compare them with the national normative resolutions for quality of wastewater and its different uses. The most relevant and locally applicable parameters described in these documents were listed, and the reference limits were defined by comparing them with those found in the scientific literature applied to the Brazilian context. This compilation represents the first step towards the incorporation of regulations for water reuse, having the Brazilian Semiarid region as a first test field, but with expandable application to different regions of the country. | RESUMO O déficit hídrico é uma problemática atual de relevância mundial. No Brasil, em especial no semiárido, essa realidade alcança níveis elevados de seca em boa parte do ano, sendo necessária a busca de alternativas mitigadoras, como o reúso planejado de águas residuárias, alternativa instaurada com sucesso nos países desenvolvidos, aplicado para diversos fins, inclusive na agricultura. No cenário nacional, mesmo diante do acentuado crescimento dessa atividade, não existem, políticas definidas de controle e monitoramento que visam minimizar impactos causados ao meio ambiente e à saúde humana. Ademais, o país não dispõe de legislação específica que contemple parâmetros da qualidade de água de reúso proveniente de esgoto doméstico. Nesse sentido, este trabalho teve como objetivo analisar as diretrizes e legislações internacionais que tratam dessa temática associadas às normativas nacionais que discorrem sobre a qualidade da água de reúso em suas diversas aplicações. Foram elencados os parâmetros de maior relevância e aplicabilidade local, descritos nesses documentos, e os limites de referência definidos a partir da comparação com a bibliografia científica aplicada ao contexto brasileiro. Essa compilação representa o primeiro passo para uma futura incorporação regulamentar da atividade de reúso de águas, tendo como campo primário de aplicação o semiárido, mas expansível às diversas regiões do país.

ABSTRACT Water scarcity is one of the main problems in the Semiarid region of Brazil, which can be mitigated by water resource management strategies. The objective of this work was to classify waters of a watershed in the Semiarid region of Brazil and select the water attributes that most affect the quality of waters used for irrigation (QWI), using multivariate statistics. The study area was the Riacho da Bica watershed, which is between the municipalities of Portalegre and Viçosa, Rio Grande do Norte, Brazil. The QWI was determined using water samples from 15 collections carried out from 2016 to 2018, in five specific points of the watershed, starting in the spring and following the water course. The water attributes evaluated were: electrical conductivity (EC), potential hydrogen (pH), and sodium (Na+), potassium (K+), magnesium (Mg2+), calcium (Ca2+), carbonate (CO32-), chloride (Cl-), and bicarbonate (HCO3-) contents. The water quality data were subjected to multivariate statistics through factorial analysis (FA) and principal component analysis (PCA). The application of multivariate statistics through FA-PCA generated four principal components. The attributes that most explained the QWI variation were potassium, calcium, and pH for Factor 01, and sodium and RAS for Factor 02. The watershed waters were classified as low risk of salinity and medium risk of sodicity (C1S2) for irrigation purposes.

ABSTRACT The objective of this study was to evaluate the effect of the conversion of secondary native vegetation (NV) to conventional systems (agriculture and pasture) in soil organic carbon (SOC) and carbon of fractions particulate organic matter (POM) and mineral-associated organic matter (MAOM) in the Brazilian semi-arid region. The study was carried out in the municipalities of Delmiro Gouveia, Inhapi and Pariconha, in Alagoas, Brazil. Soils were collected in the layers of 0-0.1, 0.1-0.2 and 0.2-0.3 m. The treatments analyzed were: agricultural crops with 4, 15 and 30 years and pasture with 10 years. As a reference, the secondary Caatinga was used. The results show that in soils with sandy texture (Neossolos Quartzarênico and Regolítico – Arenosols and Regosols, respectively), there were reductions in SOC levels and carbon in the compartment associated with minerals. The inverse can be observed in the clay-textured Argissolo (Acrisols), with 30 years of cultivation, in which there was an increase in SOC and C in the quantitative fractions of soil organic matter. In addition, despite the sandy texture of the Neossolo Regolítico, POM levels were increased in the pasture system in comparison to native vegetation, but it was not enough to recover the original SOC content of this system.

Water deficit affects plant development and the overcoming of its effects depends on the genotype, duration of stress, severity of damage and development stage of the plant at water stress. Cowpea is considered tolerant to water deficit, however, studies have shown that its yield can be reduced under this condition. Thus, the objective of this work was to evaluate the effect of water deficit on F2 populations of cowpea and select tolerant genotypes. Thirty F2 populations of cowpea and their parents (BRS-Paraguaçu, Pingo-de-Ouro-1-2, BRS-Xiquexique, CNCx-698-128G, Santo-Inácio and MNC99-510F-16-1) were evaluated in two experiments, one under induced water deficit and other under full irrigation, in the experimental field of the Embrapa Mid-North, in Teresina, State of Piauí, Brazil. A triple lattice incomplete block experiment design was used, with three replications. The experimental plots consisted of six 2-m rows, with spacing of 1.0 m between rows and 0.50 m between plants. The grain production was evaluated and its decrease related to the relative production and tolerance to stress was calculated. The grain production of the genotypes had an average decrease of 29.83% under water deficit. The genotypes from the crosses BRS-Paraguaçu x CNCx-698-128G, BRS-Xiquexique x Pingo-de-Ouro-1-2, CNCx-698-128G x BRS-Xiquexique, CNCx-698-128G x MNC99-510F-16-1, Santo-Inácio x BRS-Xiquexique and MNC99-510F-16-1 x BRS-Paraguaçu had high production and high tolerance to water deficit.

The objective of the present work was to evaluate the use of extracts of leaves and fruits of neem (Azadirachta indica Juss) as coating for papaya Formosa fruits aiming to maintain their quality during post-harvest storage. A completely randomized experimental design in a 5x5 factorial arrangement was used, with 3 replications of 2 papaya fruits per plot. The treatments consisted of five coatings with extracts of neem leaves and fruits (leaf extracts at 5 and 10%, fruit extracts at 5 and 10% and a control treatment without coating) and five storage periods (0, 3, 6, 9 and 12 days) under mean temperature of 30.4 °C and relative humidity of 42%. The fruit weight loss, external appearance, pulp firmness, titratable acidity and soluble solids were evaluated, and the fungi species on the fruit surface of each storage were identified and quantified. The treatments with extract of neem leaves and fruits at 5% had papaya fruits with best external quality and provided best control of growth of phytopathogenic fungi. Regarding external appearance, papaya fruits coated with extracts of neem leaves and fruits at 5% had a shelf life of 12 days, while those coated with extracts at 10% had a shelf life of 9 days.

The objective of this work was to evaluate Fusarium guttiforme inoculation methods and genetic resistance of pineapple accessions. Thus, three experiments were conducted: pathogen inoculation of different leaf types ( B, D and F ) of pineapple (1), pathogen inoculation of pineapple cuttings and detached D leaves (2), and identification of resistance to fusariosis in 19 pineapple accessions (3) sampled in the State of Mato Grosso, Brazil. The cultivars Pérola (susceptible to fusariosis) and BRS - Vitória (resistant to fusariosis) were used as controls. The fusariosis severity was evaluated at 10, 15, 20, 25 and 30 days after inoculation with F. guttiforme . The lesion diameters (severity level) were used in order to calculate the area under the disease progress curve (AUDPC). The inoculation of detached D leaves was the most efficient, fast and inexpensive method, and the one that most satisfactorily reproduced the disease symptoms. The period of 10 to 20 days after inoculation of the D detached leaves with the pathogen is the most suitable to evaluate the resistance of pineapple accessions to fusariosis. The lowest lesion area and AUDPC was found in the accession 1, in all evaluations. Thus, the accession 1 can be used in pineapple breeding programs for resistance to fusariosis.

The objective of the present research is to characterize the phytotoxic activity of geopropolis from the Jandaira bee (Melipona subnitida Ducke) in the state of Ceará in Northeast Brazil and to analyze its effects. Extracts were prepared in 80% v/v grain alcohol at 0.25, 0.5, 0.75, and 1.0%. Their effects were determined on seed germination, radicle elongation, and hypocotyl growth of the pasture weeds malícia (Mimosa pudica) and mata-pasto (Senna obtusifolia). Extract phytotoxicity varied as functions of plant species, application dosage, and plant organ. M. pudica was more sensitive to the inhibitory effects of geopropolis than S. obtusifolia. There was a phytotoxic effect of 50% (PE50) for S. obtusifolia in terms of seed germination and in rootlet development near the maximum applied concentrations. M. pudica had PE50 and PE90 at the minimum concentration (0.25%) and near the maximum (1.00%), respectively. Thus, geopropolis extracts from the Jandaira bee (M. subnitida) are potentially phytotoxic to certain plant species.

Our study was conducted in the experimental field of the Department of Technology and Social Sciences (DTCS) of the State University of Bahia - UNEB, Juazeiro - BA. The experimental design was comprised of randomized blocks, sub - subdivided in plots, with four replicates comprising the plots of three different shading methods, gray shading screen (GS), red shading screen (RS), and blue shading screen (BS), and the control treatment with no shading. The subplots comprised three mini - tomato cultivars (“Sweet Million”, “Red Sugar”, and “Shani”), and sub - subplots consisted of seven sampling times. The traits evaluated were: dry matter accumulation in leaves, stems, roots, and fruits, total dry matter, shoot length, root length, total number of fruits, and overall yield. The results of the growth analysis showed that dry matter accumulation in organs of mini tomatoes was similar in all treatments and that the highest total dry matter accumulation occurred under RS. In all treatments, fruit was the preferential drainage; however, the cultivar “Red Sugar” showed higher dry matter accumulation in other plant organs. “Red Sugar” also showed the highest number of fruits per plant; however, when we evaluated total productivity, “Sweet Million” and “Shani” showed similar, higher values than “Red Sugar”.

The objective of this study was to characterize the physiological acclimation responses of young plants of the dwarf coconut cultivar ̳Jiqui Green‘ associated with tolerance to conditions of multiple abiotic stresses (drought and soil salinity), acting either independently or in combination. The study was conducted under controlled conditions and evaluated the following parameters: leaf gas exchange, quantum yield of chlorophyll a fluorescence, and relative contents of total chlorophyll (SPAD index). The experiment was conducted under a randomized block experimental design, in a split plot arrangement. In the plots, plants were exposed to different levels of water stress, by imposing potential crop evapotranspiration replacement levels equivalent to 100%, 80%, 60%, 40%, and 20%, whereas in subplots, plants were exposed to different levels of soil salinity (1.72, 6.25, 25.80, and 40.70 dS m - 1 ). Physiological mechanisms were effectively limited when water deficit and salinity acted separately and/or together. Compared with soil salinity, water stress was more effective in reducing the measured physiological parameters. The magnitudes of the responses of plants to water supply and salinity depended on the intensity of stress and evaluation period. The physiological acclimation responses of plants were mainly related to stomatal regulation. The coconut tree has a number of physiological adjustment mechanisms that give the species partial tolerance to drought stress and/or salt, thereby enabling it to revegetate salinated areas, provided that its water requirements are at least partially met.

The aim of this study was to identify parents and promising hybrid combinations for the improvement of forage watermelon. Five parents were evaluated: BGCIA 996 (1), BGCIA 997 (2), BGCIA 998 (3), BGCIA 228 (4), Jojoba (5) and ten F1 hybrids, which were obtained from balanced diallel crosses. The experimental design was in a complete randomized block, with three replications. The morphoagronomic and bromatological traits were evaluated. The highlights were the progenitors BGCIA 997, BGCIA 998, BGCIA 228 and Jojoba for protein content, fruit yield, in vitro digestibility of dry matter and number of seeds, respectively. The hybrid 1x4 stood out for fruit length, seed number, and ethereal extract. The hybrid 2x3 stood out for rind and pulp thickness while the hybrids 3x4, 3x5 and 4x5 had exceptional digestibility, protein content and fruit yield, respectively. The analysis of the standard deviation of the SCA estimates of both SD (Sij- Sik) and SD (Sij- Skl) indicated that no hybrids were found that had SCA estimates twice that of SD (Sij- Sik) or SD (Sij- Skl), except for the hybrid 1x4 for the number of seeds per fruit. These results suggest that the parents were more promising than the hybrids. Similarly, the GCA estimates favor the intrapopulation method, which will promote greater efficiency in selection for genetic gains.