Calagem, gessagem, culturas de cobertura e adubação nitrogenada em sistema plantio direto: características químicas do solo, estado nutricional e produtividade do milho
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Data
2019-08-19
Autores
Fernandes, Vinicius Cábrio
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Universidade Estadual Paulista (Unesp)
Resumo
No cerrado, o Sistema Plantio Direto assume importância devido ao não revolvimento do solo, utilizar culturas de cobertura e preconizar rotação de culturas. Em área experimental no município de Selvíria – MS implantou-se o sistema plantio direto no ano agrícola 2000/01, com o objetivo de avaliar os tratamentos com diferentes modos e épocas de aplicação de calcário, culturas de cobertura e doses de N, no comportamento das culturas de milho e soja. Os resultados abordados neste trabalho, referem-se aos anos agrícolas 2015/16, 2016/2017 e 2017/18, quando utilizou-se o milho como cultura principal, o milheto e a Crotalaria juncea como culturas de cobertura, diferentes doses de calcário aplicadas durante os anos anteriores, complementadas com a reaplicação de calcário na presença e ou ausência de gesso e doses de N em cobertura. A área experimental pertence a UNESP – Campus de Ilha Solteira, sendo o solo classificado como LATOSSOLO VERMELHO distrófico com textura argilosa. O delineamento experimental utilizado foi o em blocos casualizados com os tratamentos disposto em esquema fatorial. O calcário foi aplicado em 2001, 2007 e 2012, perfazendo um total de (T1) 4,66; (T2) 6,90; (T3) 5,47; (T4) 6,11 e (T5) 0,81 t ha-1. No ano de 2016, foi realizado uma nova reaplicação de calcário, aplicando respectivamente nos tratamentos, 2,26; 4,52; 2,26; 4,52 e 0 t ha-1, acrescido para os tratamentos T3 e T4, 1,7 t ha-1 de gesso. As plantas de cobertura forma mantidas e as doses de N utilizadas anualmente foram 0, 90 e 180 kg ha-1, utilizando como fonte a uréia. As avaliações foram do estado nutricional do milho, características agronômicas do milho e valores de pH do solo, nas profundidades de 0 – 0,10, 0,10 – 0,20 e 0,20 – 0,40 m. As diferentes doses de calcário utilizadas, com e sem adição de gesso, não alteram os teores foliares de N, P, K, Ca, Mg, S, Cu, Fe, Mn e Zn, características agronômicas e produtividade de grãos do milho; a demanda por fertilizante nitrogenada pela cultura do milho é menor quando este é cultivado em sucessão a crotalária; as doses de N em cobertura proporcionaram incrementos na produtividade de grãos nos 3 anos agrícolas avaliados; a crotalaria propicia maior acidificação do solo em relação ao milheto; a aplicação de calcário em superfície em função do tempo corrige valores de pH até a profundidade de 0,20 m e doses de N de 90 a 180 kg ha-1 elevam a acidez do solo até a camada de 0,20 m de profundidade.
In the Cerrado region, the no-tillage system assumes importance because of no soil tillage, use of cover crops and crop rotation. In an experimental area in Selvíria county, Mato Grosso do Sul State, Brazil, the no-tillage system was implemented in the agricultural year 2000/01, aiming to evaluate the treatments with different modes and times of application of limestone, cover crops and N rates, on the behavior of corn and soybean crops. The results to be presented in this work refer to the agricultural years 2015/16, 2016/2017 and 2017/18, when maize was used as the main crop, millet and Crotalaria juncea as cover crops, different doses of limestone applied during the previous years, complemented by the reapplication of limestone in the presence and / or absence of gypsum and N rates in topdressing. The experimental area of UNESP - Ilha Solteira Campus has soil classified as dystrophic Red Latosol with clay texture. The experimental design was a randomized complete block with treatments arranged in a factorial scheme. Limestone was applied in 2001, 2007 and 2012, totaling (T1) 4.66; (T2) 6.90; (T3) 5.47; (T4) 6.11 and (T5) 0.81 t ha-1. In 2016, a new limestone reapplication was performed, applying respectively 2.26; 4.52; 2.26; 4.52 and 0 t ha-1, plus for treatments T3 and T4, 1.7 t ha-1 of gypsum. The cover crops were maintained and the doses of N used annually were 0, 90 and 180 kg ha-1, using urea as source. Evaluations were based on corn nutritional status, corn agronomic characteristics and soil pH values at depths of 0 - 0.10, 0.10 - 0.20 and 0.20 - 0.40 m. The results allowed to conclude that the different doses of limestone used, with and without the addition of gypsum, do not alter the leaf contents of N, P, K, Ca, Mg, S, Cu, Fe, Mn and Zn, agronomic characteristics and yield corn grains; the demand for nitrogen fertilizer for corn crop is lower when it is grown in succession to sunn hemp; N rates in cover provided increases in grain yield in the 3 agricultural years evaluated; sunn hemp leads to greater soil acidification compared to millet; applying limestone on the surface as a function of time corrects pH values up to the depth of 0.20 m and N rates from 90 to 180 kg ha-1 increase soil acidity to the 0.20 m depth layer.
In the Cerrado region, the no-tillage system assumes importance because of no soil tillage, use of cover crops and crop rotation. In an experimental area in Selvíria county, Mato Grosso do Sul State, Brazil, the no-tillage system was implemented in the agricultural year 2000/01, aiming to evaluate the treatments with different modes and times of application of limestone, cover crops and N rates, on the behavior of corn and soybean crops. The results to be presented in this work refer to the agricultural years 2015/16, 2016/2017 and 2017/18, when maize was used as the main crop, millet and Crotalaria juncea as cover crops, different doses of limestone applied during the previous years, complemented by the reapplication of limestone in the presence and / or absence of gypsum and N rates in topdressing. The experimental area of UNESP - Ilha Solteira Campus has soil classified as dystrophic Red Latosol with clay texture. The experimental design was a randomized complete block with treatments arranged in a factorial scheme. Limestone was applied in 2001, 2007 and 2012, totaling (T1) 4.66; (T2) 6.90; (T3) 5.47; (T4) 6.11 and (T5) 0.81 t ha-1. In 2016, a new limestone reapplication was performed, applying respectively 2.26; 4.52; 2.26; 4.52 and 0 t ha-1, plus for treatments T3 and T4, 1.7 t ha-1 of gypsum. The cover crops were maintained and the doses of N used annually were 0, 90 and 180 kg ha-1, using urea as source. Evaluations were based on corn nutritional status, corn agronomic characteristics and soil pH values at depths of 0 - 0.10, 0.10 - 0.20 and 0.20 - 0.40 m. The results allowed to conclude that the different doses of limestone used, with and without the addition of gypsum, do not alter the leaf contents of N, P, K, Ca, Mg, S, Cu, Fe, Mn and Zn, agronomic characteristics and yield corn grains; the demand for nitrogen fertilizer for corn crop is lower when it is grown in succession to sunn hemp; N rates in cover provided increases in grain yield in the 3 agricultural years evaluated; sunn hemp leads to greater soil acidification compared to millet; applying limestone on the surface as a function of time corrects pH values up to the depth of 0.20 m and N rates from 90 to 180 kg ha-1 increase soil acidity to the 0.20 m depth layer.
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Palavras-chave
Crotalária, Milheto, Nitrogênio, Calcário, Gesso, Zea mays, Sunn hemp, Millet, Nitrogen, Limestone, Gypsum