Crescimento e nutrição mineral de mudas de Taxibranco-da-terra-firme (Sclerolobium paniculatum Vogel ) micorrizadas e adubadas com diferentes fontes de fosfato natural.

Abstract

The effects of combinations between different sources of natural P and arbuscular mycorrhizal fungi (FMAs) inoculation on the growth and absorption nutrient of Taxi-branco-da-terra-firme (Sclerolobium paniculatum Vogel) were evaluated under greenhouse conditions at Departamento de Solos, Faculdade de Ciências Agrárias do Pará-FCAP, Belém, Pará state, Brazil .in 1995. The experiment was carried out in 3 Kg plastic pot, containing sieved yellow alic latosol, fumigated with methyl bromide, under randomized blocks experimental design with four replications per treatment. The seeds collected in Embrapa/Cpatu-Belém/ PA were sowed in plastic tray, containing ured sand. The sources of natural P used were Pirocaua, Jandía and Trauíra. Three FMAs Acaulospora sp, Gigaspora margarita and Scutellospora heterogama which were previously multiplied in culture pot, containing Brachiaria decumbens as host plant, were tested Inoculation was done at transplanting by depositing approximately 20g of soil inoculum, containing 206, 430 and 1904 spores, respectively, underneath the seedlings. It was found that all treatments exhibited positive growth. Plants treated with Acaulospora sp fungi and Pirocaua fertilized grew much better than those with control. The different sources of natural P demonstrated different effects on mycorrhizal root infection. Plants inoculated with Acaulospora sp and fertilized with Jandía ahsowed the highest percentage of root colonization, followed by Scutellospora heterogama and Gigaspora margarita. In relation to nutrient concentration, the greatest increment was found in N and K. More study should be done on obtaining the satisfactory crop production with reduced fertilization cost, by using FMAs in low fertility soil of Amazon.