Qualidade da água de um reservatório e do solo da zona ripária sob diferentes usos na região semiárida do Rio Grande do Norte

Reservoirs are artificial ecosystems intermediate between rivers and lakes widely used in the Brazilian semiarid region as a way to provide water supply due to the said region’s water scarcity. The use of water from these supply sources for multiple uses, along with occupation and utilization of its riparian zone without proper management, directly influences the increased nutrient flow into aquatic environments, there with contributing to the acceleration of eutrophication. The semi-arid region is characterized by peculiar weather conditions, such as severe evaporation, high temperatures with little variation throughout the year and long water residence time, making it susceptible to prolonged drought occurrence, which tends to concentrate the nutrients in reservoirs, which favors the development of eutrophic conditions. Moreover, it is common soil use and occupation by carrying out activities with potential environmental impact on natural resources such as agriculture, livestock farming and lack of sanitation. The aim of this study is both to evaluate the water quality of the Cruzeta Reservoir, located in the semiarid region of Rio Grande do Norte, during a prolonged drought period, and assess the quality of its riparian zone soil under different uses, by monitoring physical-chemical variables. Along the prolonged drought, high levels of turbidity, suspended solids, nutrients and chlorophyll a were verified as present, therefore featuring low water quality. In the riparian zone of Cruzeta Reservoir, the areas under use of agriculture and livestock farming appeared as one of the main diffuse sources of nutrients to the said reservoir, featuring the highest levels of phosphorus and nitrogen in the soil, originated from decomposition of animal excreta and from the use of fertilizers, creating a tendency to increased eutrophication of such water supply source. The indicators of water and soil quality are useful for monitoring and evaluating the conservation status of natural resources, allowing the control and mitigation of the reservoir eutrophication process. This study confirmed the hypothesis that the reduction of water level, resulting from prolonged drought event, aggravates the symptoms of eutrophication; and also that using the soil under severalways modifies the physic chemical properties of the soil, having livestock farming and agriculture as the usages with greatest potential towards yielding P and N to the aquatic environment.

Análise do grau de proteção do Aquífero Barreiras em perímetros sob fertilização química a partir de dados hidrogeofísicos - área da bacia do Rio Catu-RN

The use of chemical fertilization in arable perimeters provides increased productivity, though it can eventually lead to a qualitative depreciation of groundwater sources, especially if such sources are unconfined in nature. In this context, this thesis presents results from an analysis of the level of natural protection of the Barreiras Aquifer in an area located on the eastern coast of the Rio Grande do Norte State - Brazil. Such an aquifer is clastic in nature and has an unconfined hydraulic character, which clearly makes it susceptible to contamination from surface ground loads with contaminants associated with the leaching of excess fertilizers not absorbed by ground vegetation. The methodology used was based on the use of hydro-geophysical data, particularly inverse models of vertical electrical soundings (VES) and information from well profiles, allowing the acquisition of longitudinal conductance cartographies (S), data in mili-Siemens (mS), and the vulnerability of the aquifer. Such maps were prepared with emphasis to the unsaturated overlying zone, highlighting in particular its thickness and occurrence of clay lithologies. Thus, the longitudinal conductance and aquifer vulnerability reveal areas more susceptible to contamination in the northeast and east-central sections of the study area, with values equal to or less than 10mS and greater than or equal to 0,50, respectively. On the other hand, the southwestern section proved to be less susceptible to contamination, whose longitudinal conductance and vulnerability indices are greater than or equal to 30mS and less than or equal to 0,40, respectively.

Análise do grau de proteção do Aquífero Barreiras em perímetros sob fertilização química a partir de dados hidrogeofísicos - área da bacia do Rio Catu-RN

The use of chemical fertilization in arable perimeters provides increased productivity, though it can eventually lead to a qualitative depreciation of groundwater sources, especially if such sources are unconfined in nature. In this context, this thesis presents results from an analysis of the level of natural protection of the Barreiras Aquifer in an area located on the eastern coast of the Rio Grande do Norte State - Brazil. Such an aquifer is clastic in nature and has an unconfined hydraulic character, which clearly makes it susceptible to contamination from surface ground loads with contaminants associated with the leaching of excess fertilizers not absorbed by ground vegetation. The methodology used was based on the use of hydro-geophysical data, particularly inverse models of vertical electrical soundings (VES) and information from well profiles, allowing the acquisition of longitudinal conductance cartographies (S), data in mili-Siemens (mS), and the vulnerability of the aquifer. Such maps were prepared with emphasis to the unsaturated overlying zone, highlighting in particular its thickness and occurrence of clay lithologies. Thus, the longitudinal conductance and aquifer vulnerability reveal areas more susceptible to contamination in the northeast and east-central sections of the study area, with values equal to or less than 10mS and greater than or equal to 0,50, respectively. On the other hand, the southwestern section proved to be less susceptible to contamination, whose longitudinal conductance and vulnerability indices are greater than or equal to 30mS and less than or equal to 0,40, respectively.

Historical global map of NH4+ and NO3- application in synthetic nitrogen fertilizer, link to NetCDF files

This paper provides a method for constructing a new historical global nitrogen fertilizer application map (0.5° × 0.5° resolution) for the period 1961-2010 based on country-specific information from Food and Agriculture Organization statistics (FAOSTAT) and various global datasets. This new map incorporates the fraction of NH+4 (and NONO-3) in N fertilizer inputs by utilizing fertilizer species information in FAOSTAT, in which species can be categorized as NH+4 and/or NO-3-forming N fertilizers. During data processing, we applied a statistical data imputation method for the missing data (19 % of national N fertilizer consumption) in FAOSTAT. The multiple imputation method enabled us to fill gaps in the time-series data using plausible values using covariates information (year, population, GDP, and crop area). After the imputation, we downscaled the national consumption data to a gridded cropland map. Also, we applied the multiple imputation method to the available chemical fertilizer species consumption, allowing for the estimation of the NH+4/NO-3 ratio in national fertilizer consumption. In this study, the synthetic N fertilizer inputs in 2000 showed a general consistency with the existing N fertilizer map (Potter et al., 2010, doi:10.1175/2009EI288.1) in relation to the ranges of N fertilizer inputs. Globally, the estimated N fertilizer inputs based on the sum of filled data increased from 15 Tg-N to 110 Tg-N during 1961-2010. On the other hand, the global NO-3 input started to decline after the late 1980s and the fraction of NO-3 in global N fertilizer decreased consistently from 35 % to 13 % over a 50-year period. NH+4 based fertilizers are dominant in most countries; however, the NH+4/NO-3 ratio in N fertilizer inputs shows clear differences temporally and geographically. This new map can be utilized as an input data to global model studies and bring new insights for the assessment of historical terrestrial N cycling changes.

O efeito da adubação foliar na variedade de batata (Solanum tuberosum) de indústria “LADY ROSETTA”

A batata está sujeita a stresses bióticos (doenças, pragas, infestantes) e abióticos (condições climáticas, secura, excesso de água, ou fitotoxicidade provocada por herbicidas, entre outros). Os adubos foliares contendo nutrientes (macro e micronutrientes) poderão contribuir para uma melhor nutrição da planta, para além de exercer uma ação benéfica ao nível do potencial hídrico da folha e sua proteção contra os diversos inimigos bióticos. Instalou-se um ensaio em Marinhais na variedade de batata de indústria Lady Rosetta, para avaliar o efeito da adubação foliar de uma gama de adubos foliares “Humigel”, contendo, entre outros nutrientes, o enxofre e o potássio, numa situação de fitotoxidade causada pela aplicação de um herbicida. O ensaio foi instalado com um dispositivo experimental de parcelas totalmente aleatórias, com 4 repetições. Os tratamentos foram a aplicação de “Humigel” e sem aplicação (testemunha). A produção comercial nas parcelas com “Humigel” foi significativamente mais elevada (48 192 kg/ha) do que nas parcelas testemunha (43 458 kg/ha). Não se registaram diferenças significativas ao nível do número de tubérculos (comercial e total) por planta, nem ao nível dos parâmetros de qualidade (peso específico e teste de fritura).

Fontes de matéria orgânica para a formulação de fertilizantes organominerais peletizados no desenvolvimento da cultura do sorgo

Organo-mineral fertilizers have been used to both meet plants’ nutritional needs and reduce producers’ reliance on mineral fertilizers. This practice improves both the use of nutrients by plants and the soil structure due to the organic matter in these fertilizers. This study aimed to determine the effect of organic matter sources in the composition of organomineral fertilizers and compare it to the effect of traditional mineral fertilizers when it comes to the initial development of sorghum. Research was carried out in a greenhouse at the Federal University of Uberlandia, in Uberlandia, Minas Gerais, Brazil. Sorghum seeds of grain-bearing simple hybrid 1G100 were used in the seeding process. The experiment followed a randomized complete block design in a 4 x 3 + 2 factorial arrangement. Factors included four levels (50, 75, 100 and 125% of 450 kg ha-1, which is the recommended dose for sorghum crops), three organic matter sources in the composition of the organomineral fertilizers (sewage sludge, filter cake, and peat), a control (100% mineral fertilizer), and an untreated check (no fertilizers). Each experimental plot consisted of four plants divided into two pots. Oxisol was used in all pots. Analyses were performed at 30 and 60 days after seeding (DAS) and targeted: plant height, stem diameter, chlorophyll A, chlorophyll B, and leaf area. After this period, plants were removed from the soil, and had their aerial parts isolated to be dried in an air-forced oven before measurement of their dry mass. Means of the organomineral fertilizers outperformed those of both control and untreated check plots in almost all variables at 30 DAS. The only exception was variable stem diameter, in which organomineral fertilizers outperformed untreated check plots only. Sorghum fertilized with organomineral fertilizers also showed positive results in the variables analyzed at 60 DAS: even with dose reduction, their means were similar to those found in control plots. Organomineral fertilizers had higher means in some variables, such as diameter and dry mass of the aerial part, than both control and untreated check plots. In the conditions set in this study and considering the variables herein reported, organomineral fertilizers can substitute mineral fertilizers in the initial development of sorghum, even with some dose reductions.

Desempenho agronômico do milho com diferentes fontes e doses de nitrogênio

Nitrogen (N) is one of the major nutrients nutrients absorbed in corn crops, for this reason, nitrogen based fertilizers are expensive and suffer large losses to the environment. Therefore, a diversity of fertilizers, known as special or of enhanced efficiency fertilizers, has been commercialized. The aim of this study was to evaluate the effect of different sources and levels of nitrogen fertilization in coverage, for agronomic characteristics and corn grain productivity, cultivated in the Cerrado region. The experiment was installed in 2015, in Monte Carmelo-MG. The experimental design utilized was a RCBD with four replications. The treatments consisted of five N sources (common urea, polymerized urea, urea combined with NBPT (thiophosphate N-n-butiltriamida or N-n-butiltriamida of thiophosphoric acid), organomineral combined or not with NBPT), five topdress N levels (40, 80, 120, 160 and 200 kg ha-1) and a control (no N topdressing). The evaluated parameters were: the first spike insertion height (FSIH), plant height (PH), stem diameter (DC), number of rows per spike (RS), number of grains per row (GR), spike length (SL), spike diameter (SD), prolificacy (EP), 1,000-grain weight (TGW), leaf chlorophyll index (LCI), content of foliar nutrients, dry matter in aerial part of the plant (DM) and productivity (PG). The results showed that, with the exception of stem diameter, there was no significant statistical difference between sources of nitrogen, indicating that the organomineral source is as efficient as a mineral source. Regardless of the source, the addition of N fertilizers in increasing doses promoted enhanced development of corn plants, increased chlorophyll content, stem diameter, leaf N content, crude protein and productivity. For most phytotechnical features, there was no significant statistic difference in treatments compared to control.

Análise das principais variáveis na flotação industrial do complexo de mineração de Tapira - MG

Faced with an agribusiness expansion scenario and the increase in fertilizer consumption due to the exponential growth of the population, it is necessary to make better use of existing reserves, by obtaining products of better quality and in adequate quantities to meet demand national. In Tapira Mining Complex, Vale Fertilizantes, the phosphate concentrate is produced with content of 35.0% P2O5 from ore with content of about 8.0% P2O5, which are intended to supply Complex Industrial Uberaba and Araxá Minero Chemical Complex for the production of fertilizers. The industrial flotation step responsible for the recovery of P2O5 and hence the viability of the business is divided into the crumbly, grainy and ultrathin circuits, and, friable and granular concentrate comprise the conventional concentrated. Today only 14.7% of the mass which feeds the mill product becomes, the remainder being considered losses in the process, and the larger mass losses are located in the waste of flotation, representing 42.3%. From 2012 to 2014, the daily global mass recovery processing plants varied from 12.4 to 15.9% while the daily metallurgical recovery of P2O5 from 48.7 to 82.4%. By the degree of variability, it appears that the plant operated under different conditions. Seen this, this study aimed to analyze the influence of operational and process variables in P2O5 mass and metallurgical recoveries of industrial flotation circuits of grainy, crumbly and ultrathin. And besides was made an analysis of the effect of ore variables, as degrees, hardnesse and the ore front 02 percentage, in global recoveries of processing plant and the effect of dosages of reagents in the recoveries obtained from the bench flotation using the experimental design methodology. All work was performed using the historical database of Vale Fertilizantes of Tapira-MG, where all independent variables were dimensionless as the experimental range used. To make the statistical analysis it used the response surface technique and the values of the independent variables that maximize recoveries were found by canonical analysis. In the study of industrial flotation circuit crispy were obtained from 41.3% mass recovery and 91.3% metallurgical recovery P2O5, good values for the circuit, and the highest recoveries occur for solids concentration of the new flotation power between 45 and 50%, which values are assigned to the residence time of the pulp in cells and industrial flotation columns. The greater the number of ore heaps resumed on the higher the mass recovery, but in this scenario flotation becomes unstable because there is enormous weight variation in the feed. Higher recoveries are obtained for mass depressant dosage exceeding 120 g / t for synthetic collector dosage of 11.6%. In the study of industrial flotation circuit of the granulate were obtained 28.3% to 79.4% mass recovery and metallurgical recovery of P2O5 being considered good values for the circuit. Higher recoveries are obtained when the front ore 02 percentage is above 90%, because the ore of this front have more clear apatite. Likewise recoveries increase when the level of pulp rougher step is highest due to the high mass of circulating step receives loads. In the analysis of industrial flotation circuit of the ultrafine were obtained 23.95% of mass recovery, and the same is maximized to depressant dosage and the top collector 420 and 300 g / t, respectively. The analysis of the influence of variables ore, it was observed that higher recoveries are obtained for ores with P2O5 content above 8.0%, Fe2O3 content in the order of 28% forward and 02 of ore percentage of 83%. Hard ore percentage has strong influence on recoveries due to mass division in the circuit that is linked to this variable. However, the hard ore percentage that maximizes recoveries was very close to the design capacity of the processing plant, which is 20%. Finally, the study of the bench flotation, has noted that in friable and granular circuits the highest recoveries are achieved for a collector dosage exceeding 250 g / t and the simultaneous increase of collector dosage and synthetic collector percentage contributes to the increase recovery in the flotation, but this scenario is suitable to produce a concentrate poorer in terms of P2O5 content, showing that higher recovery is not always the ideal scenario. Thus, the results show the values of variables that provide higher recoveries in the flotation and hence lower losses in the waste.

(Table 2) Grain composition of sediments from ODP Hole 161-974B and from beach samples

Miocene to Pleistocene sand and sandstone were recovered at Ocean Drilling Program Site 974 in the Tyrrhenian Basin and Sites 976 and 977 in the Alboran Basin. Sand detrital modes were determined for 45 samples from these sites, as well as 10 samples of Spanish beach sand. At Site 974, the Pleistocene section includes a number of volcaniclastic (vitric ash) and terrigenous sand layers; the latter are heterogeneous and contain sedimentary and metamorphic lithic fragments. Submarine canyon and onshore drainage patterns suggest that the most likely source of this sediment is the Tiber River drainage basin in central Italy, where a Pleistocene volcanic field is superimposed on Apennine orogenic rocks. In contrast, the Miocene sand in Unit III at Site 974 may have been derived from local basement highs. The quartzolithic composition and preponderance of metamorphic and sedimentary lithic debris in sand samples from Unit II at Site 976, Unit I at Sites 977 and 978, and Unit I at Site 979 are consistent with derivation from metamorphic rocks and sedimentary cover sequences that crop out in the Betic Cordillera of southern Spain (976-978) and in the Rif of Northern Africa (979). The sedimentary to metamorphic lithic fragment ratios in these samples reflect the relative proportion of metamorphic and sedimentary rocks exposed in onshore source terranes. In contrast, the source of the few quartzose Pleistocene sands at Site 976 was likely the Flysch Trough Units that crop out near Gibraltar. The significant volcanic component in certain intervals at Sites 976 (upper Miocene) and 977 (lower Pliocene to Miocene) is consistent with widespread volcanic activity during basin inception and development. Mean sand detrital modes for sand subgroups from both the Alboran and Tyrrhenian Basin sites plot in the Recycled Orogenic and Magmatic Arc compositional fields of Dickinson et al. (1983, doi:10.1130/0016-7606(1983)94<222:PONAPS>2.0.CO;2), reflecting the hybrid tectonic histories of these basins.

Nd isotopes an geochemistry of bulk deep sea sediments of the Atlantic Ocean

Nd isotopes preserved in fossil fish teeth and ferromanganese crusts have become a common tool for tracking variations in water mass composition and circulation through time. Studies of Nd isotopes extracted from Pleistocene to Holocene bulk sediments using hydroxylamine hydrochloride (HH) solution yield high resolution records of Nd isotopes that can be interpreted in terms of deep water circulation, but concerns about diagenesis and potential contamination of the seawater signal limit application of this technique to geologically young samples. In this study we demonstrate that Nd extracted from the > 63 µm, decarbonated fraction of older Ocean Drilling Program (ODP) sediments using a 0.02 M HH solution produces Nd isotopic ratios that are within error of values from cleaned fossil fish teeth collected from the same samples, indicating that the HH-extractions are robust recorders of deep sea Nd isotopes. This excellent correlation was achieved for 94 paired fish teeth and HH-extraction samples ranging in age from the Miocene to Cretaceous, distributed throughout the north, tropical and south Atlantic, and composed of a range of lithologies including carbonate-rich oozes/chalks and black shales. The strong Nd signal recovered from Cretaceous anoxic black shale sequences is unlikely to be associated with ferromanganese oxide coatings, but may be derived from abundant phosphatic fish teeth and debris or organic matter in these samples. In contrast to the deep water Nd isotopic signal, Sr isotopes from HH-extractions are often offset from seawater values, suggesting that evaluation of Sr isotopes is a conservative test for the integrity of Nd isotopes in the HH fraction. However, rare earth elements (REE) from the HH-extractions and fish teeth produce distinctive middle REE bulge patterns that may prove useful for evaluating whether the Nd isotopic signal represents uncontaminated seawater. Alternatively, a few paired HH-extraction and cleaned fish teeth samples from each site of interest can be used to verify the seawater composition of the HH-extractions. The similarity between isotopic values for the HH-extraction and fish teeth illustrates that the extensive cleaning protocol applied to fish teeth samples is not necessary in typical, carbonate-rich, deep sea sediments.

(Table 1, Page 94) Elemental abundances in ferromanganese nodules and crusts from the Pernambuco Plateau and guyots off northeast Brazil

Ferromanganese deposits, mostly manganese crusts, are common in elevations along the northeastern Brazilian continental margin. Association of the deposits with more or less altered basaltic rock can be observed. On the Pernambuco Plateau and Ceara Guyot, ferromanganese deposits occur associated with phosphatic material and nodules. The mineralogical composition of the ferromanganese deposits indicates a predominance of the manganese oxide phase dMnO2. Low contents of Mn and Cu are characteristic of their chemical composition. Fe and Mn in the deposits probably precipitated from the sea water.

WARMING AND CHRONIC HIGH NUTRIENT MANIPULATIONS YIELD DIFFERING LEGACY EFECTS ON THE SOIL MICROBIAL COMMUNITY AND NUTRIENT POOLS IN THE LOW ARCTIC

Climate warming is predicted to increase summer air temperatures in the Arctic, warming soils and enhancing microbial decomposition of soil organic matter. Given the size of the soil carbon stores in the Arctic, even a fraction of its release as CO2 to the atmosphere could result in a positive feedback to climate warming. Fertilizers have been used in the past to quickly increase soil solution nutrients pools to mimic predicted concentrations under climate warming. However, because it may have inadvertent affects on the soil microbial community, fertilizer-induced patterns in microbial decomposition may be unrealistic. This study aimed to better understand the proposed mechanism of enhanced microbial decomposition under nutrient addition and warming treatments to discern whether warming alone is enough to stimulate enhanced microbial decomposition, or if nutrients in excess (i.e. chronic high nutrient additions) are necessary to yield such a response. I investigated the impacts of 10 years of greenhouse summer warming, chronic low nutrient factorial addition (5 g N and 1g P m-2 year-1, respectively), and chronic high nutrient factorial addition (10 g N and 5g P m-2 year-1, respectively) treatments on a mesic birch hummock tundra ecosystem near Daring Lake, NWT, Canada. Soil microbial nutrient pools, soil solution nutrient pools, and microbial community structure were measured in the upper organic, lower organic, and uppermost mineral soil depth intervals of all treatment plots in Spring 2014. Interestingly, the low nutrient additions did not yield any significant trends, yet the warming treatment increased soil bacterial richness suggesting a legacy effect of warming from the previous summers. Enhanced microbial nutrient uptake occurred only in the high nutrient addition treatments, and did not significantly alter soil carbon at least within the ten year period of this experiment. Together, these results and the absence of significant impacts of the low nutrient and greenhouse warming treatments suggests that nutrient and carbon cycling in these low arctic soils may be resilient against climate warming, at least over the initial decades.

Physico-geochemical and mineral composition of neem tree soils and relation to organic properties

The Neem tree, the oil of which has a long history of pesticide, fertilizer and medicinal use in India, has been studied extensively for its organic compounds. Here we present a physical, mineralogical and geochemical database resulting from the analyses of two Neem soil profiles (epipedons) in India. Neem tree derivatives are used in the manufacture of a variety of products, from anti-bacterial drugs and insecticides to fertilizers and animal feeds. A preliminary geochemical and mineralogical analysis of Neem soils is made to explore the potential for chemical links between Neem tree derivatives and soils. Physical soil characteristics, including colour, texture and clay mineralogy, suggest the two pedons formed under different hydrological regimes, and hence, are products of different leaching environments, one well-drained site, the other poorly drained. Geochemically, the two Neem soils exhibit similarities, with elevated concentrations of Th and rare earth elements. These elements are of interest because of their association with phosphates, especially monazite and apatite, and the potential link to fertilizer derivatives. Higher concentrations of trace elements in the soils may be linked to nutritional derivatives and to cell growth in the Neem tree.

Grain size, morphometry and mineralogy of airborne input in the Canary basin: evidence of iron particle retention in the mixed layer

[EN]Aeolian dust plays an important role in climate and ocean processes. Particularly, Saharan dust deposition is of importance in the Canary Current due to its content of iron minerals, which are fertilizers of the ocean. In this work, dust particles are characterized mainly by granulometry, morphometry and mineralogy, using image processing and scanning northern Mauritania and the Western Sahara. The concentration of terrigenous material was measured in three environments: the atmosphere (300 m above sea level), the mixed layer at 10 m depth, and 150 m depth. Samples were collected before and during the dust events, thus allowing the effect of Saharan dust inputs in the water column to be assessed. The dominant grain size was coarse silt