The most common direct method used to estimate crop evapotranspiration is the lysimetric method. Hence, the objective of this work was to construct, install and evaluate the performance of three weighing lysimeters to estimate the water demand of wine grapes (Vitis viniferal L.) cv. Syrah. The lysimeters, 1.2 m width, 2.0 m long, and 1.0 depth, were Construção e Calibração...
RESUMOO manejo inadequado da irrigação pode resultar no acúmulo de sais no solo, cuja intensidade depende da qualidade da água utilizada na irrigação, da fração de lixiviação adotada e da demanda evapotranspirativa da região. O presente trabalho teve como objetivo avaliar os atributos físicos e químicos dos solos do perímetro irrigado Califórnia, localizado no extremo noroeste do Estado de Sergipe. Para tal, foram realizadas amostragens em 42 lotes, correspondendo a 16,4% dos lotes deste perímetro. As maiores concentrações de sais e de sódio ocorreram na camada superficial (0-0,2m) do solo, o que evidenciou a falta de um manejo da irrigação adequado visando ao controle da salinidade. O aumento do pH do solo foi correlacionado significativamente com a porcentagem de sódio trocável, atingindo valores acima de 9,5. Correlações positivas significativas foram observadas entre a condutividade elétrica e os teores de Ca e Mg, indicando que sais desses íons podem estar se acumulando no solo pela ascensão do lençol freático, associado à ausência de lixiviação e drenagem.Palavras-chave: salinidade, condutividade elétrica, sodicidade. ABSTRACTThe improper irrigation management may result in the accumulation of salts in the soil profile, which intensity depends on the irrigation water quality, the leaching fraction adopted and on the evapotranspiration demand of the region. The objective of the present study was to study the physical and chemical characteristics of the soils in the irrigated district of California, located in the northwest of the State of Sergipe.Thus, soil sampling were made in 54 lots, corresponding to 16.4% of the lots of this district. The highest salt and sodium concentrations occurred in the shallowest soil layer (0-0.2m), evidencing the lack of an appropriate irrigation management in order to control the salinity build up. The increasing of the soil pH was significantly correlated to the exchangeable sodium percentage, reaching values over 9.5. Significant positive correlations were observed between the electrical conductivity and the Ca and Mg content, indicating that salts of both ions could be accumulating in soil by the capillary rise of the water table, associated to the lack of leaching and drainage.
VARIAÇÃO SAZONAL NA EVAPOTRANSPIRAÇÃO DE PLANTAS JOVENS DE LIMA ÁCIDA ‘TAHITI’ Cláudio Ricardo da Silva1; José Alves Júnior1; Tonny José Araújo da Silva1; Marcos Vinícius Folegatti1; Luis Fernando de Souza Magno Campeche21Departamento de Engenharia Rural, Escola Superior de Agricultura Luiz de Queiróz, Universidade de São Paulo, Piracicaba-SP, csilva@esalq.usp.br2Departamento de Engenharia Agronômica, Universidade Federal de Sergipe 1 RESUMO O objetivo deste trabalho foi estudar a variação sazonal diária e horária na evapotranspiração de plantas jovens de lima ácida ‘Tahiti’ sob condições de campo. O estudo foi conduzido em Piracicaba, durante o inverno de 2003 e verão de 2004. Utilizou-se um lisímetro de pesagem eletrônica de 2,7 mde diâmetro e 0,8 mde profundidade com uma planta de dois anos de idade, localizado no centro da área experimental com 322 plantas. Todas as plantas do pomar foram irrigadas por quatro gotejadores autocompensantes, inclusive a do lisímetro. Os resultados permitiram verificar que no período de verão a média da evapotranspiração da cultura (ETc) foi de 1,50 mm dia-1 decrescendo a 0,66 mm dia-1 nos meses de inverno. O coeficiente de cultivo (Kc) médio obtido foi de 0,36 e 0,22 durante o período de verão e inverno, respectivamente. A ETc máxima para o período de inverno ocorreu às 14:00 h enquanto que no verão foi às 12:00 h. Além disso, ocorreram perdas por evaporação diária noturna de 17,4 % e 13,4% da ETc para o período de inverno e verão respectivamente. A curva de evaporação do solo (Ke) foi semelhante em ambos os períodos estudados. UNITERMOS: citros, lisímetro, coeficiente de cultivo, demanda hídrica SILVA, C. R. da; ALVES JÚNIOR, J.; SILVA, T. J. A. da; FOLEGATTI, M. V.; CAMPECHE, L. F. de S. M.; SEASONAL VARIATION IN EVAPOTRANSPIRATION OF YOUNG ‘TAHITI’ACID LIME TREES 2 ABSTRACT The objective of this study was to investigate seasonal variations in hourly and daily evapotranspiration (ETc) of acid lime ‘Tahiti’ trees under field conditions, defining values of crop coefficients. The study was carried out in Piracicaba, Brazil, during the winter of 2003 and the summer of 2004. Aweighing lysimeter of 2.7 mdiameter and 0.8 mdepth was planted with a two-year-old tree that was located at the center of an experimental area with 322 trees. The lysimeter tree was irrigated, like others in the plot, by four pressure compensated emitters. The average ETc was 1.50 mmday-1 in the summer and dropped to 0.66 mm day-1 in winter months. The average seasonal crop coefficient (Kc) was 0.36 and 0.22 for summer and winter, respectively. The maximum Etc time was at noon in the summer and at 2 pm in the winter. Moreover, night soil evaporation represented 17.4% and 13.4% of daily ETc in winter and summer. The soil evaporation curve (Ke) in both seasons showed similar results. KEYWORDS: citrus, lysimeter, crop coefficient, water requirements
This study evaluated the contribution of potassium (K) nutrition and application of wastewater depths to the agronomic performance of colored cotton. Treatments consisted of five irrigation depths (50, 75, 100, 125 and 150% of crop evapotranspiration -ETC) and five K doses (0, 50, 100, 150 and 200% of the recommendation for the crop) and an absolute control irrigated with 100% ETCwater depth and fertilized with 100% N-P-K recommendation. Each treatment and the control had four replicates. Plant height, stem diameter, leaf area and shoot dry matter accumulation of cotton were evaluated at 130 days after emergence (DAE), whereas seed cotton weight was evaluated at 135 DAE. Our findings indicate that the use of treated domestic sewage for 100% ETCreplacement promotes greater gains of weight and growth in colored cotton without the need for K fertilization, evidencing the potential of wastewater for colored cotton for sustainable agriculture.
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