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ABSTRACT The aim of this study was to evaluate the spatial dependence between chemical properties of the soil and yield components in the soybean using precision farming techniques. Samples of the soil and plants were taken from georeferenced points to determine the chemical properties of the soil and the yield components. The results were submitted to Pearson correlation analysis, descriptive statistics and geostatistics. The coefficient of variation showed a wide range of distribution for the chemical attributes of the soil, with the highest indices being found for the levels of available phosphorus (102%) and potassium (72.65%). Soil pH and organic matter showed a coefficient of variation of 5.96 and 15.93% respectively. Semivariogram analysis of the yield components (productivity, 1,000-seed weight and number of seeds) and the chemical properties of the soil (organic matter, pH, phosphorus, potassium, calcium, magnesium, boron, manganese and zinc) fitted the spherical model with moderate spatial dependence, with values ranging from 200 to 700 m. Spatial distribution by means of map interpolation was efficient in evaluating spatial variability, allowing the identification and quantification of regions of low and high productivity in the production area, together with the distribution of soil attributes and their respective levels of availability to the soybean plants.

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objetivou-se avaliar a extensão e a intensidade da dependência espacial da fertilidade de um Latossolo Vermelho-Amarelo distrófico, cultivado sob plantio direto, utilizando, de forma conjunta, técnicas de geoestatística e estatística multivariada. O experimento foi conduzido em uma área cultivada com soja em plantio direto no município de Rio Verde - GO. O solo foi amostrado nas profundidades de 0-0,05 m e 0,05-0,15 m, em uma malha amostral com 44 pontos. Os atributos avaliados foram pH em CaCl2, Ca, Mg, Al, P, K, H+Al, CTC, SB, V e MO. Os dados foram analisados por meio da análise da estatística descritiva seguida de uma análise de componentes principais de forma a gerar componentes que expliquem a maior parte da variação dos atributos. A geoestatística foi utilizada para verificar a existência e quantificar o grau de dependência espacial utilizando os componentes principais. A matéria orgânica apresentou maior continuidade espacial devido às características do sistema de plantio direto. De maneira geral, a área apresentou baixa fertilidade para o cultivo da soja, como diferente padrão de distribuição espacial entre camadas.The objective was to assess the extent and intensity of the spatial dependence of the fertility of a Red-Yellow Latosol, cultivated under a non-tillage system, by using both geo-statistical techniques and multivariate statistics. The experiment was conducted in an area planted with soybeans under a non-tillage system, in the city of Rio Verde, Goiás, Brazil. The soil was sampled at depths of 0-0.05m and 0.05-0.15m, in a sampling grid with 44 points. The attributes evaluated were the pH of CaCl2, Ca, Mg, Al, P, K, H+Al, CEC, BS, V and MO. The data were analyzed using descriptive statistical analysis, followed by principal component analysis, in order to generate components which would explain most of the variations in the attributes. Geo-statistics was used to check and quantify the degree of spatial dependence, using the principal components. Multivariate analysis, associated with the geo-statistical analysis, showed satisfactory results for the spatial distribution of fertility. Organic matter showed greater spatial continuity due to the characteristics of the no-tillage system. In general, the area presented low fertility for the cultivation of soybeans, as well as different patterns of spatial distribution between layers.

O conhecimento da variabilidade espacial da fertilidade do solo é muito importante, principalmente, para a agricultura de precisão. Assim, durante o ano agrícola 2009/2010, no município de Selvíria (MS), no Cerrado Brasileiro, objetivou-se analisar a variabilidade espacial de atributos da fertilidade num Latossolo Vermelho Distroférrico sob plantio direto. Foi instalada a malha de amostragem para a coleta de solo, com 120 pontos amostrais, numa área de 3,0 ha e declive homogêneo de 0,055 m m-1. Foram determinados os teores de P disponível, de matéria orgânica, valor de pH (CaCl2), teores de K+, Ca+2, Mg+2, valores de saturação por bases e por alumínio, nas profundidades de 0-0,10 m e 0,10-0,20 m. Efetuou-se a análise descritiva clássica, com auxílio do software estatístico SAS, e em seguida foram modelados semivariogramas para todos os atributos, obtendo-se as respectivas validações cruzadas e mapas de krigagens com o GS+ 7.0. As maiores variabilidades dos atributos químicos analisadas pelo coeficiente de variação ocorreram na camada de 0,10-0,20 m de profundidade do solo. Todos os atributos químicos pesquisados apresentaram dependência espacial, sendo possível mapear a área em estudo. Por representar a continuidade espacial dos semivariogramas obtidos no presente estudo, os valores dos alcances geoestatísticos recomendados para os atributos ora pesquisados deverão estar compreendidos entre 40,2 e 113,1 metros.Knowledge of the spatial variability of soil fertility is very important, especially in precision agriculture. Thus during the 2009/2010 agricultural year, in the city of Selva (MS) in the Brazilian Cerrado, the objective was to analyse the spatial variability of the fertility attributes of a Dystropheric Red Latosol under a no-tillage system. A sampling grid was installed to collect soil samples, with 120 sampling points in an area of 3.0 ha and on an even slope of 0.055 m m-1. The available phosphorus content, organic matter content, values of pH (CaCl2), levels of K+, Ca+2, Mg+2, values of base and aluminum saturation were all determined at depths of 0 to 0.10m and 0.10 to 0.20m. A classic descriptive analysis was carried out with the help of the SAS statistical software, and semivariograms were then modeled for all attributes, giving the respective cross-validations and kriging chartswith the GS+ 7.0 software. The largest variability, in the chemical attributes analysed by the coefficient of variation, occurred in the soil-depth layer of 0.10-0.20m. All studied chemical attributes showed spatial dependence, it being possible to map the study area. As they represent the spatial continuity of the semivariograms obtained in this study, the values of the geostatistical ranges recommended for those attributes here studied, should be between 40.2 and 113.1 metres.

A grande quantidade de resíduos industriais que constituiu atualmente sérios problemas ambientais tem alertado para a utilização adequada desses materiais que, além de reduzir os impactos ambientais, tem demonstrado potencial para utilização na agricultura. O objetivo deste estudo foi avaliar os efeitos químicos da aplicação de diferentes doses de escória de siderurgia e óxido de magnésio em dois solos sob o cultivo de café arábica. O estudo foi desenvolvido em casa de vegetação do Centro de Ciências Agrárias da Universidade Federal do Espírito Santo, em vasos de 10 dm³. O delineamento experimental foi instalado em blocos casualizados, com distribuição fatorial de 2 x 3 x 6, com três repetições, sendo os fatores: dois solos (Latossolo Vermelho-Amarelo distrófico de textura argilosa e Latossolo Vermelho-Amarelo distrófico de textura média); três insumos (calcário como controle e escória de siderurgia e óxido de magnésio como resíduos); seis doses dos materiais corretivos (0; 25; 50; 75; 100 e 125% da necessidade de calagem). Após 180 dias de cultivo, procedeu-se as análises de pH, H+ + Al3+, Al3+, Ca2+ e Mg2+. Os resultados mostraram que as aplicações de doses crescentes de escória e óxido de magnésio até o limite estudado neste trabalho favorecem um decréscimo da acidez do solo. O óxido de magnésio demonstrou maior potencial como corretivo de acidez de solo e como fonte de magnésio para o solo.The large amount of industrial waste which currently causes serious environmental problems has demonstrated the need for the appropriate use of those materials which not only reduce environmental impact but have shown potential for agricultural use. The aim of this study was to evaluate the chemical effects of different amounts of slag and magnesium oxide on two soils planted with coffea arabica. The study was carried out using pots of 10 dm³ in a greenhouse at the Center for Agrarian Sciences of the Federal University of Espirito Santo. The experimental design was of randomized blocks with a factorial distribution of 2 x 3 x 6, and three replications, the factors being: two soils (dystrophic red-yellow clay loam and dystrophic red-yellow medium-texture loam), three additives (limestone as control and slag and magnesium oxide as waste), six amounts of corrective materials (0; 25; 50; 75; 100 and 125% of the required liming). After 180 days of culture, analysis of pH, H+ + Al3+, Al3+, Ca2+ e Mg2+ was carried out. The results showed that applications of increasing doses of magnesium oxide and slag, up to the limit of this study, further a decrease in soil acidity. Magnesium oxide has shown the greatest potential for soil-acidity correction and also as a source of magnesium for the soil.

Objetivou-se avaliar a eficiência do esterco bovino na adubação orgânica na cultura da batata. O experimento foi realizado no município de Esperança/PB, em Neossolo Regolítico. A cultivar utilizada foi a Monalisa, onde o delineamento utilizado foi de blocos casualizados, com três repetições. Os tratamentos foram constituídos de aplicação de esterco bovino em quantidades de 0; 3; 6; 9; 12; 15; 18; 21 e 24 t ha-1 e 10 t ha-1 com a complementação de NPK com percentagens de 0; 12,5; 25; 37,5; 50; 62,5; 75; 87,5 e 100% da fórmula 120-80-90 (N-P2O5-K2O), calculada conforme a análise de solo. As variáveis avaliadas foram: número e peso médio de tubérculos por planta, produção total, produção comercial, perdas de produção e matéria seca de tubérculos. O uso de esterco bovino e esterco bovino à adição de NPK proporcionaram aumento no peso de tubérculos por planta, produção total e produção comercial de tubérculos de batata. Desta forma, observa-se que o esterco bovino é uma boa alternativa como adubação orgânica para os produtores de batata.In the Paraíba state the potato shows a low yield, due to the rain seasonality allied to the low soil fertility. This study aimed to evaluate the bovine manure efficiency in the organic fertilization of potato. The experiment was carried out in Esperança county, in a Regolithic neossoil. The design used was randomized blocks, with bovine manure application in quantities of 0; 3; 6; 9; 12; 15; 18; 21 and 24 t ha -1 and 10 t ha -1 of bovine manure + NPK with percentages of 0; 12.5; 25; 37.5; 50; 62.5; 75; 87.5; and 100% of the formula 120-80-90 ( N-P2O5-K2O ), calculated by the soil analysis. The variables evaluated were: number and weight of tubers per plant, total yield and commercial; yield losses and dry matter of tubers. The use of bovine manure and bovine manure + NPK provided an increase in weight of tubers per plant, total yield and commercial potato tubers. This way, it is observed that the bovine manure is a good alternative as organic fertilization to the potato producers of this county.

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ABSTRACT Cowpea is widely grown in the Brazilian semiarid region, however, due to excess salts in the soil and irrigation water constantly low crop productivity has been observed. Accumulation of salts in the soil, growth and biomass partition of cowpea under salt stress and phosphorus fertilization was evaluated in this study. The assay was conducted in a greenhouse in Mossoró, State of Rio Grande do Norte, Brazil, from September to December 2015, using a Alfissol Latosolic with low phosphorus content. The experiment was carried out in a randomized block design in a factorial 5 x 3 arrangement, consisting of five water salinity levels (0.5, 1.5, 2.5, 3.5 and 4.5 dS m-1) and three doses of superphosphate (60, 100 and 140% of the recommended dose for crop - 60 kg ha-1 of P2O5), with five repetitions. The plants of cowpea cv. Paulistinha were cultivated for 49 days after sowing in lysimeters with 8 dm3 capacity. During this period was determined the accumulation of salts in the soil, growth and biomass partition plants. Water with salinity higher than 1.5 dS m-1 increased soil salinity above the crop's threshold of 4.9 dS m-1, 21 days after sowing. Increased salinity impaired growth and biomass partition of cowpea plants, with greater accumulation of dry matter in the leaves and stem in comparison to the root. Hinghest dose of superphosphate promoted greater growth of cowpea plants.

Resumo O objetivo deste estudo foi analisar, utilizando a geoestatística e o sistema de classificação fuzzy, a fertilidade de uma área experimental com base em atributos químicos do solo e sua relação com a produtividade do café conilon. O estudo foi realizado na fazenda experimental do INCAPER-ES. As amostras de solo foram coletadas na profundidade de 0 - 0,2 m, sendo analisados os atributos: fósforo, potássio, cálcio e magnésio, alumínio, soma de bases, capacidade de troca catiônica a pH 7 e saturação por bases. Os dados foram submetidos a uma análise descritiva, exploratória e à analise geoestatística. Utilizou-se um sistema de classificação fuzzy utilizando os atributos descritos para inferir sobre a fertilidade do solo e sua relação com a produtividade da cultura. A possibilidade de fertilidade apresentou relação espacial positiva com a produtividade da cultura, com valores mais elevados desta onde a possibilidade de solo fértil é superior.