The evapotranspiration process is critical to studies on the water balance and water demand of crops and can be determined by several methods. A widely-used method, despite its high installation costs, is weighing lysimeters, which consists of a box over a balance connected to a load cell that monitors variations in the soil-water-plant-atmosphere system. The aim of this study was to develop and calibrate six weighing lysimeters (with dimensions of 1.5 x 1.5 x 1.2 m each) by high precision load cells, testing their ability to measure water mass changes in field conditions and cultivated with common bean (Phaseolus vulgaris L.), in the city of Tangará da Serra, in the state of Mato Grosso, Brazil. All lysimeters showed coefficients of determination higher than 0.99, as well as Willmott indexes, correlation and high confidence indexes, indicating that the equipment is suitable for measuring mass variations in water balance and evapotranspiration studies, representing the reality which occurred in the field.

ABSTRACT:The objective of this study was to define the best irrigation level in a sprinkler system, submitted to nitrogen doses in covering in the municipality of Tangará da Serra -MT, for two cultivars of peanut (Arachis hypogaea L.). The experiment was carried out in the experimental field of the State University of Mato Grosso (UNEMAT), located geographically in latitude 14º39'S; Longitude 57º25'W, at 440 meters of altitude. The climate is classified as tropical humid megathermal (Aw), with annual average rainfall of 1,830 mm and average temperature of the air 24.4ºC. The soil is classified as Dystroferric Red Latosol. The experimental design was in randomized blocks where 4 levels (30, 70, 110 and 150% of the reference evapotranspiration, ET0) were determined. In each level, 0, 30, 60, 90 and 120 Kg ha -1 of nitrogen were applied in two peanut cultivars IAC Tatu ST and IAC Runner 886. Each plot had 24 lines per 12 m length, 4 lines for each dose of N in each level and cultivar with 0.45 m spacing between lines. The irrigation level that provided the highest productivity in the development cycle for both peanut cultivars was 110% of ET0. While the levels of 30 and 70% of the ET0 allowed greater growth in height, but smaller productivities, the 150% ET0 level showed higher yields in the husk, and lower grain yield due to the high germination rate of the grain yet in the plant. For Tatu cultivar, doses of 60 to 90 kg ha -1 of N increase productivity, whereas for Runner cultivar nitrogen fertilization did not affect productivity.

COEFICIENTE DUAL DE CULTIVO DO MILHO PIPOCA EM TANGARÁ DA SERRA – MT     CLEONIR ANDRADE FARIA JUNIOR1; RIVANILDO DALLACORT2; PAULO SERGIO LOURENÇO DE FREITAS3; JOÃO DANILO BARBIERI4; ROBERTO REZENDE5 E WILLIAM FENNER6   1Doutorado no Programa de Pós-Graduação em Agronomia, Universidade Estadual De Maringá, Av. Colombo, nº 5790 – Zona 07, bloco j45, 2º piso, CEP - 87020-900, Maringá/PR/Brasil, cleonir.junior@hotmail.com 2Professor do Programa de Pós-Graduação em Ambiente e Sistema de Produção Agrícola, Universidade do Estado de Mato Grosso, Rodovia MT  358, Km 07 (s/n) – Jardim Aeroporto, CEP: 78300-000, Tangará da Serra/MT/Brasil, rivanildo@unemat.br 3Professor no Programa de Pós-Graduação em Agronomia, Universidade Estadual De Maringá, Av. Colombo, nº 5790 – Zona 07, bloco j45, 2º piso, CEP - 87020-900, Maringá/PR/Brasil, pslfreitas@uem.br 4Doutorando no Programa de Pós-Graduação em Agronomia, Universidade Estadual De Maringá, Av. Colombo, nº 5790 – Zona 07, bloco j45, 2º piso, CEP - 87020-900, Maringá/PR/Brasil, jd.barbieri@hotmail.com 5Professor no Programa de Pós-Graduação em Agronomia, Universidade Estadual De Maringá, Av. Colombo, nº 5790 – Zona 07, bloco j45, 2º piso, CEP - 87020-900, Maringá/PR/Brasil, rrezende@uem.br 6Doutor no programa de Pós-Graduação em Agricultura Tropical, Universidade Federal de Mato Grosso, Av. Fernando Corrêa da Costa, nº 2367, Bairro Boa Esperança, CEP – 78060-900, Cuiabá/MT/Brasil. fennerwilliam@gmail.com     1      RESUMO   O objetivo deste trabalho foi determinar o coeficiente duplo da cultura do milho pipoca para o município de Tangará da Serra - MT, utilizando lisímetros de pesagem. O experimento no campus da Universidade do Estado de Mato Grosso- UNEMAT, sendo o solo classificado como Latossolo Vermelho distroférrico, com textura muito argilosa. A semeadura foi realizada no dia 02/05/2015, nos seis lisímetros de pesagem, previamente calibrados com coeficientes de determinação acima de 0,99, para a bordadura foi utilizada uma semeadora de plantio direto, com espaçamento entre linhas de 0,45 m, a colheita foi realizada manualmente no dia 16/08/2015. As irrigações foram realizadas conforme a evapotranspiração potencial calculada diariamente pelos lisímetros e irrigados quando necessário por sistema de aspersão composto de 6 aspersores, com coeficiente de uniformidade de distribuição de 86%. Durante o desenvolvimento da cultura foram medidos diariamente a variação de massa dos microlisímetros por meio de pesagem, determinando a evaporação de água no solo em todas as fases da cultura. Durante o ciclo da cultura a temperatura média foi de 24,5°C e um aporte hídrico total de 571,4 mm. Os valores médios de Kcb obtidos na fase inicial, pleno desenvolvimento e maturação, foram de 0,7, 1,10 e 0,3 respectivamente.   Palavras-Chave: evapotranspiração, Zea mays L. subsp. everta, lisímetro de pesagem.     FARIA JUNIOR, C. A.; DALLACORT, R.; FREITAS, P. S. L. DE; BARBIERI, J. D.; REZENDE, R.; FENNER, W. DUAL CROP COEFFICIENT OF MAIZE CORN OF TANGARÁ DA SERRA – MT     2      ABSTRACT   The objective of this work was to determine the double coefficient of maize corn crop for the municipality of Tangará da Serra - MT, using weighing lysimeters. The experiment was conducted in State University of Mato Grosso – UNEMAT’s campus, and the soil was classified as dystroferric Red Latosol, with very clayey texture. Sowing was carried out on May 2, 2015, in the six weighing lysimeters, previously calibrated with determination coefficients above 0.99. For the border, a no-till seeding with row spacing of 0.45 m was used. Harvest was performed manually on 08/16/2015. Irrigations were performed according to the potential evapotranspiration calculated daily by the lysimeters and irrigated when necessary by a sprinkler system composed of 6 sprinklers, with distribution uniformity coefficient of 86%. During the development of the culture, mass variation of microlysimeters was measured daily by weighing, determining the evaporation of water in the soil in all phases of the culture. During the culture cycle the average temperature was 24.5 ° C and the total water supply was 571.4 mm. The average Kcb values obtained in the initial phase, full development and maturation phases were 0.7, 1.10 and 0.3 respectively.   Keywords: evapotranspiration, zea mays l. subsp. everta, weighing lysimeter.

No abstract

No abstract