Congo grass grown in rotation with soybean affects phosphorus bound to soil carbon

Revista Brasileira de Ciência do Solo

Alexandre Merlin¹  Zhenli L. He²  Ciro Antonio Rosolem¹ 

[1] ,University of Florida IFAS Indian River Research and Education CenterFlorida,USA

关键词: crop rotation;    no-till;    organic P;    phosphorus fractionation;    fracionamento do P;    fósforo orgânico;    rotação de culturas;    semeadura direta;   

DOI  :  10.1590/S0100-06832014000300020

来源: SciELO

【 摘 要 】

The phosphorus supply to crops in tropical soils is deficient due to its somewhat insoluble nature in soil, and addition of P fertilizers has been necessary to achieve high yields. The objective of this study was to examine the mechanisms through which a cover crop (Congo grass - Brachiaria ruziziensis) in rotation with soybean can enhance soil and fertilizer P availability using long-term field trials and laboratory chemical fractionation approaches. The experimental field had been cropped to soybean in rotation with several species under no-till for six years. An application rate of no P or 240 kg ha-1 of P2O5 had been applied as triple superphosphate or as Arad rock phosphate. In April 2009, once more 0.0 or 80.0 kg ha-1 of P2O5 was applied to the same plots when Congo grass was planted. In November 2009, after Congo grass desiccation, soil samples were taken from the 0-5 and 5-10 cm depth layer and soil P was fractionated. Soil-available P increased to the depth of 10 cm through growing Congo grass when P fertilizers were applied. The C:P ratio was also increased by the cover crop. Congo grass cultivation increased P content in the soil humic fraction to the depth of 10 cm. Congo grass increases soil P availability by preventing fertilizer from being adsorbed and by increasing soil organic P.

【 授权许可】

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