Resumo

COVACEVICH, Fernanda; SAINZ ROZAS, Hernán René; BARBIERI, Pablo  e  ECHEVERRIA, Hernán Eduardo. The influence of phosphorus placement on growth and indigenous root mycorrhizal colonization of wheat crop. Cienc. suelo [online]. 2005, vol.23, n.1, pp.39-45. ISSN 1850-2067.

The aim of the study was to evaluate the influence of phosphorus (P) fertilizer placement (in-furrow incorporated or broadcast) on growth and root mycorrhizal colonization of wheat (Triticum aestivum L).crop. Experiments were set up during the 2001 and 2002 growing seasons at four productive sites of Balcarce and Lobería with different initial availability of Bray-P. Treatments were: N: nitrogen broadcast; N broadcast and P incorporated in furrow at seedling; N and P broadcast; Control without fertilizer application. In situations with low P availability (lower than 11 mg kg-1), the P incorporated was more efficient than the P broadcast treatment at increasing grain yield. In situations with P contents higher than 11 mg kg-1, differences in grain yield were lower between the treatments of P placement. Phosphorus fertilization negatively affected mycorrhizal colonization until 15.9 mg kg-1. At P concentrations higher than 15.9 mg kg-1 mycorrhizal colonization remained stable at the lowest level (6.85 %). The P broadcast depressed mycorrhizal colonization; however mycorrhizal depression was lower than when P was incorporated. The lowest difference in grain yield between the P placement treatments, particularly at soil P contents higher than 11 mg kg-1, could be consequence of a higher mycorrhizal colonization when P was broadcast. The fertilization strategy could be broadcast the fertilizer at rates which permit to increase the soil P at levels (between 11 and 15 mg kg-1) in order to attain high yields of wheat crop without extremely depress mycorrhizal colonization. In this way, this could permit simplicity at the time of fertilization and to attain adequate grain yield taking into account the agroecosystems sustainability.

Palavras-chave : Phosphorus placement; Mycorrhizal colonization; Triticum aestivum.

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