Can tropical grasses grown as cover crops improve soil phosphorus availability?

Autor(es)

Almeida, D. S. ^[1] ; Menezes-Blackburn, D. ^{[2, 3]} ; Rocha, K. F. ^[1] ; de Souza, M. ^[1] ; Zhang, H. ^[2] ; Haygarth, P. M. ^[2] ; Rosolem, C. A. ^[1]

Afiliação do(s) autor(es)

^[1] Sao Paulo State Univ, Dept Crop Sci, BR-18610307 Botucatu, SP - Brazil

^[2] Univ Lancaster, Lancaster Environm Ctr, Lancaster LA1 4YQ - England

^[3] Sultan Qaboos Univ, Dept Soils Water & Agr Engn, POB 34, Al Khod 123, Muscat - Oman

• Tipo de documento: Artigo Científico
• Fonte: SOIL USE AND MANAGEMENT; v. 34, n. 3, p. 316-325, SEP 2018.
• Citações Web of Science: 1

Resumo

Tropical grasses grown as cover crops can mobilize phosphorus (P) in soil and have been suggested as a tool to increase soil P cycling and bioavailability. The objective of this study was to evaluate the effect of tropical grasses on soil P dynamics, lability, desorption kinetics and bioavailability to soya bean, specifically to test the hypothesis that introducing grass species in the cropping system may affect soil P availability and soya bean development according to soil P concentration. Three grass species, ruzi grass (Urochloa ruziziensis), palisade grass (Urochloa brizantha) and Guinea grass (Megathyrsus maximus), were grown in soils with contrasting P status. Soya bean was grown after grasses to assess soil P bioavailability. Hedley P fractionation, microbial biomass P, phytase-labile P and the diffusive gradient in thin films were determined, before and after cultivation. It was found that grasses remobilized soil P, reducing the concentration of recalcitrant P forms. The effect of grasses on changing the P desorption kinetics parameters did not directly explain the observed variation on P bioavailability to soya bean. Grasses and microorganisms solubilize recalcitrant organic P (P-o) forms and tropical grasses grown as cover crops increased P bioavailability to soya bean mainly due to the supply of P by decomposition of grass residues in low-P soil. However, no clear advantages in soya bean P nutrition were observed when in rotation with these grasses in high-P soil. This study indicates that further advantages in soya bean P nutrition after tropical grasses may be impeded by phytate, which is not readily available to plants. (AU)

• Processo FAPESP: 14/23707-5 - Disponibilidade de fósforo e produtividade de soja em rotação com braquiária ruziziensis
• Beneficiário: Danilo Silva Almeida
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 15/04200-0 - Conservação do fósforo em sistemas de produção agrícola
• Beneficiário: Ciro Antonio Rosolem
• Modalidade de apoio: Auxílio à Pesquisa - Regular