Efeito de doses, fontes e granulometria de enxofre na produção e estado nutricional dos capins mombaça e piatã
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2018-11-27
Autores
Santos, Luiz Felipe de Melo
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Universidade Estadual Paulista (Unesp)
Resumo
O enxofre é, provavelmente, o macronutriente menos empregado nas adubações, o que resulta na redução de rendimento e qualidade de forragem. Entre os nutrientes, apresenta um importante papel por participar em várias funções biológicas, faz parte da composição dos aminoácidos cisteína, metionina e cistina, acetil-CoA, bem como de enzimas que participam da fotossíntese e o metabolismo do nitrogênio. O objetivo foi avaliar a produção e estado nutricional dos capins Piatã e Mombaça em resposta a aplicação de doses e fontes de sulfato e enxofre elementar em Argissolo Vermelho Amarelo. Em virtude disso, realizou-se dois experimentos em casa de vegetação na Faculdade de Ciências Agrárias e Tecnológicas, UNESP, Campus de Dracena – SP, o primeiro foi no período de janeiro a março de 2017 e o segundo de outubro a janeiro de 2018, com o capim Piatã e de Mombaça, respectivamente. O delineamento experimental foi em blocos casualizados com quatro repetições, arranjados em esquema fatorial, 4x5, com quatro fontes de enxofre (Gipsita, Fosfogesso, S elementar em pó e S elementar pastilhado) e cinco doses de enxofre (0, 50, 100, 150 e 200 mg kg-1).Foram determinados os parâmetros biométricos como número de perfilhamento, massa seca da parte aérea (MSPA) e massa seca de raízes (MSR). O estado nutricional das plantas foi avaliado por meio da leitura SPAD e análise de macronutrientes N, P, K, Ca, Mg, S na parte aérea das plantas. Avaliou-se também o enxofre residual do solo e o pH do solo. Os resultados demonstraram que adubação com S aumentou a produção de MSPA, MSR, número de perfilhos, quantidade de folhas por colmo, índice SPAD e promoveu uma melhor qualidade de estado nutricional da forragem em ambos os experimentos. A granulométrica das fontes apresentou uma forte influencia na disponibilização de S, o que é possível de ser constado pelos menores incrementos na produção e absorção de S verificados com o uso da fonte SEPA em relação às demais fontes, tanto na espécie Urochloa brizantha quanto da espécie Megathyrsus maximum. De forma geral a aplicação ideal de S foi essencial para otimizar o rendimento dos capins Piata e Mombaça em todas as fontes testadas de S, enquanto a baixa oferta de S resulta em desequilíbrio nutricional e menor rendimento.
Sulfur is probably the least used macronutrient in fertilization, which results in reduced yield and forage quality. Among nutrients, it plays an important role because it participates in several biological functions, is part of the composition of the amino acids cystine, methionine and cysteine, acetyl-CoA, as well as enzymes involved in photosynthesis and nitrogen metabolism. The objective was to evaluate the production and nutritional status of the Piatã and Mombasa grass in response to the application of doses and sources of sulfate and elemental sulfur in Yellow Red Ultisol. In view of that, two greenhouse experiments were carried out at the Faculty of Agrarian and Technological Sciences, UNESP, Dracena Campus - SP, the first one was in the period from January to March 2017 and the second from October to February 2018, with Piatã grass and Mombasa grass, respectively. The experimental design was in randomized blocks with four replications, arranged in a factorial scheme, 4x5, with four sulfur sources (Fosfogesso, Grajau, S-Elementar and Sulfurgran) and five doses of sulfur (0, 50, 100, 150 e 200 mg kg-1). Biometric parameters such as tillering number, shoot dry mass and roots dry mass were determined. The nutritional status of the plants was evaluated by SPAD reading and analysis of N, P, K, Ca, Mg and S macronutrients in shoot dry mass. Residual sulfur and soil pH were also evaluated. The results showed that S fertilization increased the yield of MSPA, MSR, number of tillers, number of leaves per stem, SPAD index and promoted a better quality of forage nutritional status in both experiments. The granulometric of the sources had a strong influence on the availability of S, which is possible to be consisted of the smaller increases in the production and absorption of S verified with the use of the SEPA source in relation to the other sources, both in the species Urochloa brizantha and of the species Megathyrsus maximum. In general, the ideal application of S was essential to optimize the yield of the Piata and Mombasa grasses in all tested sources of S, while the low supply of S results in nutritional imbalance and lower yield.
Sulfur is probably the least used macronutrient in fertilization, which results in reduced yield and forage quality. Among nutrients, it plays an important role because it participates in several biological functions, is part of the composition of the amino acids cystine, methionine and cysteine, acetyl-CoA, as well as enzymes involved in photosynthesis and nitrogen metabolism. The objective was to evaluate the production and nutritional status of the Piatã and Mombasa grass in response to the application of doses and sources of sulfate and elemental sulfur in Yellow Red Ultisol. In view of that, two greenhouse experiments were carried out at the Faculty of Agrarian and Technological Sciences, UNESP, Dracena Campus - SP, the first one was in the period from January to March 2017 and the second from October to February 2018, with Piatã grass and Mombasa grass, respectively. The experimental design was in randomized blocks with four replications, arranged in a factorial scheme, 4x5, with four sulfur sources (Fosfogesso, Grajau, S-Elementar and Sulfurgran) and five doses of sulfur (0, 50, 100, 150 e 200 mg kg-1). Biometric parameters such as tillering number, shoot dry mass and roots dry mass were determined. The nutritional status of the plants was evaluated by SPAD reading and analysis of N, P, K, Ca, Mg and S macronutrients in shoot dry mass. Residual sulfur and soil pH were also evaluated. The results showed that S fertilization increased the yield of MSPA, MSR, number of tillers, number of leaves per stem, SPAD index and promoted a better quality of forage nutritional status in both experiments. The granulometric of the sources had a strong influence on the availability of S, which is possible to be consisted of the smaller increases in the production and absorption of S verified with the use of the SEPA source in relation to the other sources, both in the species Urochloa brizantha and of the species Megathyrsus maximum. In general, the ideal application of S was essential to optimize the yield of the Piata and Mombasa grasses in all tested sources of S, while the low supply of S results in nutritional imbalance and lower yield.
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Palavras-chave
Sulfato, Megathyrsus maximum, Urochloa brizantha, Enxofre elementar, Sulphate, Elemental sulfur