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Soil Phosphorus Bioavailability and Soybean Grain Yield Impaired by Ruzigrass
Author(s) -
Almeida Danilo S.,
Rocha Kassiano F.,
Souza Murilo,
Delai Lucas B.,
Rosolem Ciro A.
Publication year - 2018
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2017.08.0451
Subject(s) - agronomy , crop rotation , soil water , crop , phosphorus , soil carbon , crop yield , growing season , biology , environmental science , chemistry , soil science , organic chemistry
Core Ideas There have been suggestions that ruzigrass increases soil P availability. Ruzigrass was grown in rotation with soybean from 2012 to 2016. The observed effect was opposite from the expected under long‐term field conditions. Crop rotation with ruzigrass resulted in a lower soybean grain yield than fallow.Under no‐till farming systems, the use of crop rotations with species adapted to low P soils may enhance soil P availability through P cycling. Growing ruzigrass [ Urochloa ruziziensis (R. Germ. and C.M. Evrard) Morrone and Zuloaga] as a cover crop has shown to increase resin extractable P in soils. However, it is not clear how the next crop responds to ruzigrass in the long term. The objective of this study was to evaluate the long‐term effect of growing ruzigrass on soil P availability to soybean [ Glycine max (L.) Merr.]. The evaluations were performed over 5 yr on a ruzigrass–soybean crop rotation, in Botucatu, Brazil. The treatments were P rates (0, 13, and 26 kg ha − ) applied to soybean seed furrows, and ruzigrass or fallow during the off‐season. Soil samples were taken after ruzigrass desiccation, and soil P was extracted with resin (P resin ). The use of ruzigrass increased soil organic matter (SOM) by approximately 20% compared with fallow, regardless of P rates, and increased P resin concentration in the 0‐ to 10‐cm soil depth by approximately 10% with 26 kg ha − of P. Surprisingly, grain yield and soybean leaf P concentration were lower after ruzigrass compared with fallow. Resin seemed to be unsuitable to compare P availability in different cropping systems. In the long‐term, growing ruzigrass as a cover crop in the off‐season decreases P and N availability to soybean, eventually decreasing soybean grain yield. Further studies are needed to understand the mechanisms involved in this unexpected soybean response when cropped in rotation with ruzigrass.