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The objective of this study was to evaluate the influence of leaching fraction on the biometric and production characteristics and technological quality of the juice of sugarcane varieties grown in saline soil in the Brazilian semiarid region. The experimental design was in randomized blocks, with three repetitions, in a 2 × 3 × 3 factorial scheme, corresponding to two sugarcane cultivation cycles: plant cane and ratoon cane; three sugarcane varieties: RB72454, SP943206 and VAT90212; and, three leaching fractions of irrigation water: 0; 9.1; and 16.6%. Number of living leaves, number of internodes, leaf area, stem diameter, plant height, number of tillers, yield, total soluble solids content (°Brix), percentage of industrial fiber, juice purity, juice Pol%, cane Pol% and total recoverable sugar were evaluated. At the end of the two crop cycles, water use efficiency was determined. The varieties SP943206 and VAT90212 showed higher yield under leaching fraction of irrigation water of 9.1% in both cycles, and higher water use efficiency values were observed for the variety VAT90212. Application of leaching fractions to reduce soil salinity does not promote changes in the technological quality of the sugarcane varieties RB72454, SP943206 and VAT90212. RESUMO Objetivou-se neste estudo avaliar a influência da fração de lixiviação nas características biométricas, produtivas e na qualidade tecnológica do caldo de variedades de cana-de-açúcar cultivadas em solo salino no Semiárido brasileiro. O delineamento experimental foi em blocos casualizados, com três repetições, em esquema fatorial 2 × 3 × 3, sendo dois ciclos de cultivo da cana-de-açúcar: cana planta e cana soca; três variedades de cana-de-açúcar: RB72454, SP943206 e VAT90212; e, três frações de lixiviação da água de irrigação: 0; 9,1; e 16,6%. Avaliou-se número de folhas vivas, número de entrenós, área foliar, diâmetro do colmo, altura da planta, número de perfilhos, produtividade, teor de sólidos solúveis totais (°Brix), porcentagem de fibra industrial, pureza do caldo, Pol% do caldo, Pol% da cana e açúcar total recuperável. Ao final dos dois ciclos da cultura foi determinada a eficiência do uso de água. As variedades SP943206 e VAT90212 demonstraram maior produtividade sob fração de lixiviação da água de irrigação de 9,1% nos dois ciclos e maiores eficiência do uso de água foram observadas na variedade VAT90212. A aplicação de frações de lixiviação para reduzir a salinidade do solo não proporciona alterações na qualidade tecnológica das variedades RB72454, SP943206 e VAT90212 de cana-de-açúcar.

RELAÇÕES MASSA-VOLUME DO SOLO, VARIABILIDADE ESPACIAL DA RESISTÊNCIA À PENETRAÇÃO E PRODUTIVIDADE DO MILHO EM SISTEMAS DE MANEJO KAMILA BORGES CASTILHO1, JORGE WILSON CORTEZ1, NELCI OLSZEVSKI2, ALESSANDRA MONTEIRO SALVIANO3, SÁLVIO NAPOLEÃO SOARES ARCOVERDE1 1Faculdade de Ciências Agrárias, Universidade Federal da Grande Dourados - UFGD, Rodovia Dourados-Itahum, km 12, Cidade Universitária, CEP: 79.804-970, Caixa-Postal: 533, Dourados, MS, Brasil. kamila_castilho45@hotmail.com; jorge.cortez@yahoo.com.br; salvionapoleao@gmail.com. 2Engenharia Agrícola e Ambiental, Universidade Federal do Vale do São Francisco - UNIVASF, Av. Antônio C. Magalhães, 510, Country Club, CEP:48902-300, Juazeiro, BA, Brasil. nelci.olszevski@univasf.edu.br. 3Embrapa Semiárido, Rodovia BR-428, Km 152, s/n - Zona Rural, CEP: 56302-970, Petrolina, PE, Brasil. alessandra.salviano@embrapa.br. RESUMO: Estudos envolvendo as características do solo permitem melhor utilização e aplicação de tecnologias agrícolas, visando a adequada capacidade produtiva. Assim, o trabalho teve por objetivo a avaliação da influência de sistemas de manejo nas relações de massa-volume, na variabilidade espacial da resistência do solo à penetração e na produtividade da cultura do milho. Foram utilizados seis sistemas de manejo em latossolo vermelho distroférrico: sem preparo (T0); uma operação de escarificação (T1); duas escarificações e uma gradagem niveladora (T2); uma aração e quatro gradagens destorroadoras-niveladoras (T3); uma gradagem destorroadora-niveladora (T4); uma escarificação e uma gradagem destorroadora-niveladora (T5). Os valores de densidade e porosidade total observados foram considerados dentro da faixa adequada para solos argilosos. A macroporosidade apresentou valores críticos de aeração nas três camadas avaliadas dos sistemas T0 e T2, na camada de 0,00-0,05 m no sistema T3 e em todos os sistemas na camada de 0,20-0,25 m. Na espacialização da RP houve variações dos dados nos perfis do solo, sendo possível observar valores altos e muito altos (>4 MPa), que podem causar restrição ao desenvolvimento radicular das plantas. Não houve diferenças entre os sistemas de manejo na avaliação da produtividade. Palavras-chaves: agricultura de precisão, compactação do solo, geoestatística. MASS-VOLUME RELANTIONSHIPS, SPATIAL VARIABILITY OF THE SOIL MECHANICAL RESISTANCE TO PENETRATION AND CORN YIELDS IN MANAGEMENT SYSTEMS ABSTRACT: The application of technology is necessary, especially in agricultural research that studies the soil and its productive capacity. The aim of this study was to evaluate the physical characteristics of the soil and spatial variability of penetration resistance in the soil profile in cropping systems and their influence on yields in a Dystroferric Red Latosol (oxisol) in area consisting of six management systems. The density and total porosity was considered adequate; the macroporosity critical limits aeration and microporosity was considered adequate. In the maps RP there were variations of the soil data profiles, which can be observed very high peak values and RP (> 4 MPa), which may cause restriction of root growth. There were no significant differences between management systems in productivity assessment. Keywords: precision agricultural, compression, geostatistics.

Soils attributes such as granulometry and density determine the distribution of pore size and condition physical and differentiated hydraulic behavior. Thus, knowing the characteristics of the soils allow the use of more adequate management techniques that lead to the improvement of the performance of the use of this resource. The aim of this study was to evaluate the diameters of granulometric fractions and the physical-hydric behavior of sandy soils from semiarid region of Brazil. Trenches were excavated to collect, describe, and characterize the morphology of soil samples. The soil bulk density, particle density, granulometry, water retention curve, total porosity and pore size distribution were evaluated. The textural difference among soil studied is expressed with greater emphasis on the amount of macropores, high retention micropores and cryptopores. Fine and very fine sand are the most impacted granulometric fractions increasing macroporosity and reducing high tension microporosity and cryptoporosity. Luvisol with predominance of silt and clay fractions, presents a greater risk of densification and erosion, thus the use of lower irrigation levels is recommended. Acrisols and Luvisol, with predominance of fine and very fine sand fractions, present similar conditions of macroporosity and cryptopores with a low textural gradient. Acrisols and Luvisol do not present major problems regarding the reduction of hydraulic conductivity along the rofile. Lower irrigation levels with higher application frequency are suggested due to the low water retention capacity and higher risk nutrients leaching. Made available in DSpace on 2019-10-17T18:15:22Z (GMT). No. of bitstreams: 1 Granulometricfractions2019.pdf: 802903 bytes, checksum: 8c4738c1ca7d2caa2ef17fdb80ecd897 (MD5) Previous issue date: 2019

The availability of potassium (K), calcium (Ca) and magnesium (Mg) in the soil affects the nutrition and productivity of the plant cover. The Ca:Mg, Ca:K and Mg:K stoichiometric ratios indicate the nutrient load balance in the soil. However, limited attention has been paid to providing a scientific basis for how changes in land use, especially the cultivation of forage, impacts the availability and reserves of base cations in semi-arid regions, since, in these environments, fertiliser is not used. Therefore, the aim of this study was to quantify the concentrations of soil K, Ca and Mg in areas of preserved Caatinga (PC), and areas where buffel grass (BG) has been cultivated for 40 years and Leucaena grass (LE) for 11 years. Four 100 x 100 cm trenches were opened in each type of plant cover and collections were made in the 0-5, 5-10, 10-15 and 15-20 cm layers. The concentrations of K, Ca and Mg and their ratios were determined and compared using the Mann-Whitney test. The soil under buffel grass showed higher concentrations of K and Mg, and a lower concentration of Ca. Compared to PC, LE presented a lower Ca content in the 0-5 cm layer only. BG had the lowest values for the Ca:Mg and Ca:K stoichiometric ratios due to depletion of the Ca. Despite being soluble and easily leached, K remained in the soil under each type of cover, favoured by the semi-arid climate. Soil Ca, which is exported due to grazing of the produced biomass, should be replaced so as not to compromise the support capacity of seasonally dry tropical environments through the cultivation of forages. Made available in DSpace on 2021-02-19T16:18:10Z (GMT). No. of bitstreams: 1 Stoichiometric-ratios-in-the-soil-of-native-and-forage-2020.pdf: 1297823 bytes, checksum: c3aebcc2ce238c7fb677261d70090852 (MD5) Previous issue date: 2020

The objective of this study was to evaluate the potentialities and limitations of the agricultural use of representative classes of semi-arid regions of the state of Bahia, based on the pedological and evaluation of their soil characteristics. Five areas were selected where trenches were opened to collect samples for the analyses: Eutric Haplustept which presents vulnerability to physical and chemical degradation due to poor drainage with risks of erosion, waterlogging, salinization and compaction but having good natural fertility; Abrupt Kandiustalf with high vulnerability to physical degradation due to the presence of gravel and pebbles which may limit the development of deep rooting plants and mechanization but also with good natural fertility; Typic quartzipsaments and Typic Eutrustalf with no limitations related to drainage as low risk of compaction but featuring limitation of low moisture-holding capacity and nutrients; and Arenic Haplustulf wose characteristics are high vulnerability to degradation due to the drainage limitation related to the Btx horizon cementing in addition to low natural fertility and therefore is not recommended to agricultural use. However, in general, they feature no serious impediments for agricultural use. The amounts of OM is low in all soils but the use of management systems aiming at their accumulation and maintenance in appropriate levels will contribute to the CEC increase as well as to improve the chemical and physical properties. Made available in DSpace on 2018-12-06T23:33:13Z (GMT). No. of bitstreams: 1 00013765aabc90043373.pdf: 1753225 bytes, checksum: af94f733d3d5bb65710683c88e15af38 (MD5) Previous issue date: 2018-12-06

In this study we determined the concentration of metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in the water lower São Francisco River basin, to evaluate the influence of urbanization and industrialization on environmental changes in the water resource. All samples were analyzed using the IUPAC adapted method and processed in an atomic absorption spectrophotometer. The sampling stations located near the industrial areas were influenced by industrialization because they presented higher concentrations of Cd, Cr, Ni and Cu. The other sampled locations showed changes with regard the trace elements probably originating in the soil, like Fe, Zn and Pb. There was a gradual increase in the concentrations of metals, in general, in the period of highest rainfall of the hydrographic network. Overall, except for Zn and Mn, the trace elements exceeded the maximum allowed value established by national legislation (CONAMA). Lower São Francisco River basin has suffered interference from urbanization and industrialization, so awareness programs should be developed so as to control and lessen future problems.

A marcha de absorção de nutrientes, estabelecida por uma curva de acúmulo de nutrientes na planta ao longo de seu ciclo, indica a fase de desenvolvimento da cultura que apresenta maior exigência de um determinado nutriente. Objetivou-se determinar o acúmulo e exportação de macronutrientes pela cana-de-açúcar, variedade RB92579, cultivada remcondições tropicais semiáridas na Usina Agrovale, em Juazeiro-BA, região do Submédio do Vale do São Francisco. O experimento foi conduzido em um Vertissolo Hidromórfico. Foram demarcadas 03 subáreas nas quais se coletou amostras de material vegetalseparadas em folhas verdes, bainhas, folhas e bainhas mortas, pseudocolmo, colmo e a parte imatura, em dez épocas ao longo do ciclo (66, 87, 112, 133, 168, 220, 242, 280, 352 e 385 dias após o corte - DAC). As amostras foram levadas à estufa a 65 o C até peso constante para obtenção da biomassa seca, na qual foram determinados os teores de N, P, K, Ca, Mg e S. A máxima absorção dos nutrientes pela cultura da cana-de-açúcar ocorreu no período compreendido entre 220 a 352 DAC. O acúmulo de nutrientes obedeceu a seguinte ordem decrescente: K > N > Ca > S > P > Mg. A colheita é responsável pela maior exportação de nutrientes acumulados pela cultura da cana-de-açúcar, cerca de 60 a 90 % do total de nutrientes acumulados são exportados pela colheita. Durante o ciclo de cana-soca, foram utilizados pela variedade 2,50; 0,33; 5,35; 0,86; 0,19; 0,55 kg de N, P, K, Ca, Mg e S, respectivamente, para cada tonelada de colmo produzida. Made available in DSpace on 2017-11-09T18:16:16Z (GMT). No. of bitstreams: 1 Alessandra2017.pdf: 884557 bytes, checksum: 0456444e80caa71fc9313c90efaee8a7 (MD5) Previous issue date: 2017-11-09