A B S T R A C TPotassium (K) can be easily lost by the leaching process. The objective of this study was to quantify K leaching in clayey and sandy soils under increasing irrigation depths. The experiment was conducted in 2014, in a protected environment, after extraction of undisturbed soil columns, with diameter of 144 mm and height of 300 mm. The columns were arranged in a randomized complete block in a factorial design with three replicates, corresponding to eight treatments: two soil types and four water depths, equivalent to 50, 100, 150 and 200% of the amount of water necessary to bring the soil moisture to field capacity. Potassium chloride, with 58% of K 2 O, was used as K source. Water replacement in the columns was performed every three days, for a period of 81 days. After conducting joint analysis of the data according to the factor Time, a second-degree response surface model was fitted and line charts were also used to study the factors Time and Water. After the evaluations, it was found that the higher the applied water depth, the greater the percolated amount of the K + ion. Lixiviação de potássio em diferentes solos em função de lâminas de irrigação R E S U M ONeste trabalho o objetivo foi quantificar a lixiviação de K em solos argiloso e arenoso sob lâminas crescentes de irrigação. O experimento foi conduzido em 2014, em ambiente protegido, após extração de colunas de solo indeformadas, com diâmetro de 144 mm e altura de 300 mm. As colunas foram arranjadas em um delineamento em blocos completos casualizados em esquema fatorial, com três repetições, constituindo oito tratamentos, sendo dois tipos de solo e quatro lâminas de água equivalentes a 50, 100, 150 e 200% da lâmina de água necessária para levar o solo à umidade na capacidade de campo. Como fonte de K utilizou-se o cloreto de potássio com 58% de K 2 O. A reposição da água nas colunas foi realizada a cada três dias, por um período de 81 dias. Após a realização de análise conjunta dos dados de acordo com o fator Tempo, foram ajustados um modelo de superfície de resposta de segundo grau completo e os gráficos de linhas para estudo dos fatores Tempo e Água. Após avaliações concluiu-se que quanto maior a lâmina de água aplicada maior também a quantidade percolada do íon K + .

LIXIVIAÇÃO DE NITRATO EM FUNÇÃO DE LÂMINAS DE IRRIGAÇÃO EM SOLOS ARGILOSO E ARENOSO  WALTER DA COSTA MENDES1; JOSÉ ALVES JUNIOR2; PAULO CÉSAR RIBEIRO DA CUNHA3; ANDERSON RODRIGO DA SILVA4; ADÃO WAGNER PÊGO EVANGELISTA2 E DERBLAI CASAROLI2 1Prof. Mestre, Instituto Federal Goiano – Campus Urutaí, Urutaí, GO, CEP 75790-000. Doutorando, Escola de Agronomia, Universidade Federal de Goiás – Campus Samambaia, Goiânia, GO. Fone (64) 92638918. E-mail: mendeswalter2@gmail.com2Prof. Doutor, Escola de Agronomia, Universidade Federal de Goiás – Campus Samambaia, Goiânia, GO, CEP 74001-970. E-mail:josealvesufg@yahoo.com.br; awpego@bol.com.br; derblaicasaroli@yahoo.com.br3Prof. Doutor, Instituto Federal Goiano – Campus Urutaí, Urutaí, GO, CEP 75790-000. E-mail: pcdacunha@hotmail.com4Prof. Mestre, Instituto Federal Goiano – Campus Urutaí, Urutaí, GO, CEP 75790-000. E-mail: anderson.silva@ifgoiano.edu.br  1 RESUMO Este trabalho teve como objetivo avaliar a influência de lâminas de água aplicadas em solo argiloso e arenoso, sobre a lixiviação de nitrato em colunas indeformadas de solo com 144 mm de diâmetro e 300 mm de altura. O experimento foi conduzido em ambiente protegido em Urutaí, Goiás. As colunas foram arranjadas em blocos completos casualizados com três repetições. Como fonte de Nitrogênio utilizou-se o nitrato de cálcio com 15,5% de Nitrogênio Total (N). Nas colunas adubadas foram aplicadas quatro lâminas de água, equivalentes a 50%, 100%, 150% e 200% da lâmina de água obtida pela diferença de massa das colunas dos tratamentos 100%. Essa diferença foi calculada entre a massa na capacidade de campo e a massa atual (momento de se realizar irrigação). As irrigações foram realizadas a cada três dias, por um período de 81 dias. Foi realizada análise conjunta dos dados de acordo com o fator Tempo. Posteriormente foi ajustado um modelo de superfície de resposta, de segundo grau completo, para estudo dos fatores Tempo e Água, para cada tipo de solo. A movimentação de N-NO3 variou em função do tipo de solo e das lâminas de irrigação, sendo que a maior e mais rápida mobilidade vertical se deu no solo arenoso em relação ao solo argiloso. Palavras-chave: colunas indeformadas de solo, textura do solo, manejo da água.  MENDES, W. C.; ALVES JUNIOR, J.; CUNHA, P. C. R.; SILVA, A. R.; EVANGELISTA, A. W. P.; CASAROLI, DERBLAINITRATE LEACHING IN FUNCTION OF IRRIGATION ON SOILS CLAYEY AND SANDY  2 ABSTRACT This study aimed to evaluate the influence of applied water levels on nitrate leaching on undisturbed soil columns (144 mm diameter and 300 mm high) filled with a clay and a sandy soil in soil column. The experiment was conducted in a greenhouse in Urutaí, Goiás. The columns were arranged in a randomized complete block design with three replications. Calcium nitrate, with 15.5% of Total Nitrogen (N), was used as source of Nitrogen. Water depths equal to 50%, 100%, 150% and 200% of water depth corresponding to the mass difference of 100% treatment column were applied. This difference was calculated between the mass at field capacity and the current mass (time to carry out irrigation). Irrigation depths were applied every three days for a period of 81 days. Joint analysis was performed of data according to the time factor. It was later set a full second degree response surface model for the study of time and water factors for each type of soil. The movement of N-NO3 varied depending on the soil type and irrigation levels, with the greater and more rapid upward mobility occurred in sandy soil from the ground clay. Keywords: undisturbed soil cores, soil texture, water management.

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The aim of this study was to determine the effects of increasing irrigation levels on the movement of nitrate and potassium in clay soil and on crop yields for the common bean irrigated by central pivot under Brazilian Cerrado conditions. The experiment was conducted in Urutaí, Goiás, Brazil, in Dystrophic Oxisol clayey soil in 2014. Four irrigation regimes were tested, which were equivalent to 50, 100, 150 and 200% of crop evapotranspiration (ETc), estimated using the Class A tank method. The plots were arranged in a randomized complete block design with four replications; the soil solution was evaluated seven times during the cycle. Potassium chloride with 58% K 2 O was used as the potassium source, and calcium nitrate with 15.5% total nitrogen (N) as the nitrogen source. To collect the soil solutions, extractors were installed at depths of 0.20, 0.40, 0.60, 0.80 and 1.00 m. The concentrations of nitrate (NO 3 -) and potassium (K + ) were determined without filtering or digestion. At harvesting, the production components and yield were evaluated. The NO 3 -and K + levels within the soil profile varied between treatments, showing nutrient leaching below the root system for the higher irrigation treatments. Therefore, the application of appropriate irrigation techniques should reduce the leaching of NO 3 -and K + and lead to higher yields for the common bean.