Colonização micorrízica e fertilidade do solo submetido a fontes e doses de adubação nitrogenada em Brachiaria brizantha
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Data
2010-09-01
Autores
Delbem, Flavia Cristina [UNESP]
Scabora, Márcia Helena [UNESP]
Soares Filho, Cecílio Viega [UNESP]
Heinrichs, Reges [UNESP]
Ferrari, Tiago Augusto [UNESP]
Cassiolato, Ana Maria Rodrigues [UNESP]
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Editor
Editora da Universidade Estadual de Maringá (EDUEM)
Resumo
A viabilização e aumento da produção de novas cultivares podem ser obtidos com a prática da adubação nitrogenada. O objetivo desse trabalho foi verificar o efeito de fontes e doses de adubação nitrogenada, em profundidades, na colonização micorrízica e na fertilidade do solo com Brachiaria brizantha cv. Xaraés. O delineamento experimental em blocos casualizados e os tratamentos em esquema fatorial 3 x 4, envolvendo três fontes de nitrogênio (ureia, sulfato de amônio e ajifer-L40), quatro doses (0, 100, 200 e 400 kg ha-1) estudadas em duas profundidades (0-0,10 e 0,10-0,20 m), com três repetições. Por parcela, as amostras compostas, por cinco amostras simples de solo, foram coletadas, peneiradas, homogeneizadas e destinadas às análises. O uso do ajifer e da ureia proporcionou maior produtividade de massa seca da parte aérea de B. brizantha cv. Xaraés. em contrapartida, esta sofre redução à medida que as doses se elevaram. A melhor dose de adubação foi a aplicação de 100 kg ha-1 de N. As doses mais elevadas de N, na camada 0 a 0,10 m de profundidade, determinam acidificação do solo e reduzem os valores de MO, K+, Ca2+, Mg2+, SB e V%. A esporulação, mas não colonização micorrízica, é sensivelmente estimulada em elevadas doses.
The feasibility and increase in the production of new cultivars can be obtained with the practice of nitrogen fertilization. The objective of this study was to verify the effect of sources and levels of nitrogen fertilization, concerning the depths, on the percentage of mycorrhizal colonization and soil fertility when covered by Brachiaria brizantha cv. Xaraés. A randomized blocks design was used and the treatments were under a 3 x 4 factorial scheme, regarding three nitrogen sources (urea, ammonium sulfate, and ajifer-L40) and 4 nitrogen levels (0, 100, 200 and 400 kg ha-1), studied at 2 different depths (0-0.10 and 0.10-0.20 m), with 3 replications. In each plot, the soil samples, composed of 5 simple samples, were collected, sieved, homogenized and sent for analysis. The use of ajifer and urea promoted higher production of shoot dry matter of B. brizantha cv. Xaraés. on the other hand, this dry matter showed reduction with the increase of N doses. The best fertilization dose was 100 kg ha-1 of N. The increasing doses of N employed, on the depth of 0-0.10 m, resulted in soil acidification and decreased the levels of MO, K+, Ca2+, Mg2+, SB and V%. Sporulation, but not mycorrhizal colonization, was stimulated by higher applied dosages.
The feasibility and increase in the production of new cultivars can be obtained with the practice of nitrogen fertilization. The objective of this study was to verify the effect of sources and levels of nitrogen fertilization, concerning the depths, on the percentage of mycorrhizal colonization and soil fertility when covered by Brachiaria brizantha cv. Xaraés. A randomized blocks design was used and the treatments were under a 3 x 4 factorial scheme, regarding three nitrogen sources (urea, ammonium sulfate, and ajifer-L40) and 4 nitrogen levels (0, 100, 200 and 400 kg ha-1), studied at 2 different depths (0-0.10 and 0.10-0.20 m), with 3 replications. In each plot, the soil samples, composed of 5 simple samples, were collected, sieved, homogenized and sent for analysis. The use of ajifer and urea promoted higher production of shoot dry matter of B. brizantha cv. Xaraés. on the other hand, this dry matter showed reduction with the increase of N doses. The best fertilization dose was 100 kg ha-1 of N. The increasing doses of N employed, on the depth of 0-0.10 m, resulted in soil acidification and decreased the levels of MO, K+, Ca2+, Mg2+, SB and V%. Sporulation, but not mycorrhizal colonization, was stimulated by higher applied dosages.
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Palavras-chave
ajifer, sulfato de amônio, ureia, pastagem, ajifer, ammonium sulfate, urea, pasture
Como citar
Acta Scientiarum. Agronomy. Editora da Universidade Estadual de Maringá (UEM) - EDUEM, v. 32, n. 3, p. 455-461, 2010.