Fontes, doses e modos de aplicação de fósforo na recuperação de pastagem com brachiaria

Abstract

RESUMOObjetivando-se avaliar diferentes fontes, doses e métodos de aplicação de fósforo na recuperação da Brachiaria decumbens, um experimento foi conduzido na Fazenda Caminho das Pedras, município de Uberlândia-MG, em Latossolo Vermelho distrófico, textura média, entre novembro de 2003 e abril de 2004. Os tratamentos constaram de três fontes de fósforo (Superfosfato Triplo, Termofosfato magnesiano e hiperfosfato de Gafsa) nas dosagens de 0; 50; 100 e 150 kg ha -1 de P 2 O 5 , com manejo incorporado e não incorporado, em três repetições, no delineamento de blocos casualizados. Foram utilizadas parcelas de 2,0 x 5,0 m, as quais foram adubadas uniformemente com 330 kg ha -1 de N e 220 kg ha -1 K 2 O, na forma de uréia + sulfato de amônio e cloreto de potássio, respectivamente. Foi avaliada a produtividade da Brachiaria em três cortes da parte aérea, em um intervalo de 30 dias entre os cortes. A aplicação de fósforo com diferentes fontes e doses promoveu incremento na produtividade da Brachiaria, porém não houve diferença comparando-se os métodos de aplicação. A maior resposta foi obtida com 150 kg ha -1 de P 2 O 5 , na forma de superfosfato triplo com produtividade média de 2997 kg ha -1 de MS por corte, e a menor produtividade ocorreu no tratamento com 50 kg ha -1 de P 2 O 5 na forma de hiperfosfato de Gafsa. Houve aumento na porcentagem do fósforo foliar e do fósforo no solo, com aumento da dose em todas as fontes, em ambos extratores. Na avaliação dos extratores, o Mehlich-1 apresentou maior extração na fonte hiperfosfato de Gafsa, contrariando os resultados de produção.Termos para indexação: Adubação fosfatada, pastagem degradada, fosfatos. ABSTRACTThe objective of this work was to evaluate different sources, doses and methods of phosphorus application in the recovery of Brachiaria decumbens. An experiment was installed on the "Caminho das Pedras" Farm, in Uberlândia-MG, in Acroustox soil, medium texture, between November 2003 and April 2004. The treatments were three phosphorus sources (Triple Superphosphate, magnesium Thermophosphate and Gafsa hiperphosphate) in the doses of 0; 50; 100, and 150 kg ha -1 of P 2 O 5 , incorporating or not incorporating, in three repetitions, in a randomized blocks experimental design. The plots were of 2.0 x 5.0 m, that were fertilizer evenly with 330 kg ha -1 of N and 220 kg ha -1 K 2 O, using urea + ammonium sulphate and potassium chloride, respectively as fertilizer sources. The productivity of Brachiaria was evaluated in three cuts of the shoot, in an interval of 30 days between cuts. Phosphorus application with different sources and doses promoted increment in the dry matter production of Brachiaria, however, there was no significant difference in production between application methods. The greatest dry matter productivity was obtained with 150 kg ha -1 of P 2 O 5 using triple superphosphate with an average productivity of 2997 kg ha -1 of dry matter per cut. The smallest productivity was obtained applying 50 kg ha -1 of P 2 O 5 using the Gafsa hiperphosphate. With increa...

Phosphorus extracted by ion exchange resins and mehlich-1 from oxisols (latosols) treated with different phosphorus rates and sources for varied soil-source contact periods

“…However, for this same P source, MR extracted levels close to those obtained by M1, although statistically different for LVA and in particular, for LV soil (Table 7). A similar result was reported by Ieiri et al (2010), who also extracted less P using AR than M1, from a medium-textured dystrophic Red Latosol fertilized with Gafsa RPh.…”

Sources and rates of residual phosphorus for Marandu palisadegrass grown in Western São Paulo

“…Similar results were obtained by Ieiri et al (2010) when studied three sources of P2O5 (Triple superphosphate, magnesium thermophosphate and hiperphosphate of Gafsa) in rates of 0, 50, 100 and 150 kg ha -1 , found that in the interactions of rates with sources of phosphorus, for the three sources mentioned there was adjustment to linear function for phosphorus content in shoot, suggesting continued increase in the accumulation of this nutrient in the applied doses. It is observed that leaf P contents are in agreement with the recommended by Werner et al (1997), i.e.…”

“…Similarly Ieiri et al (2010) by evaluating the effect of thermophosphate, hyperphosphate and Triple Superphosphate, at rates of 0, 50, 100 and 150 kg ha -1 in Brachiaria pasture and performing only three cuts observed average dry matter yield of 2,590 kg ha -1 for the application of the highest rate. Means followed by the same letter in the column do not differ from each other by Tukey test at 5% probability.…”

“…The Brazilian Cerrado presents favorable conditions for production and exploitation of livestock on pasture systems with large areas for livestock, but many of these are in some state of degradation, due to the lack of soil correction for fertilization absence (Ieiri et al, 2010). Considering that livestock is mostly extensive, there is the need to recover these areas and to increase forage production through fertilization.…”

“…P is important for enhancing forage nutritional value, as it influences in plant height, according to Bennett et al (2009). Several authors have reported the positive effect of phosphorus fertilization in DMY, with increased production (Lima et al, (2007), Benett et al (2009), Guedes et al (2009), Ieiri et al (2010). However, the efficiency of phosphorus fertilization is influenced by several factors, as soil type and source used.…”