Iniluence of vesicular-arbuscular mycorrhizal tungi sources and leveis of phasphorus on tho grawth ol cal !orage.

Abstract

The efiecis ol vesicular-arbuscular mycorrhizae (VAM), sources (Triple superphosphate and Patos de minas rock phosphate) and phosphorus leveis (0, 30 and 60 kg ol P 205/ha), on dry matter yield, concentraten and P uptake by oat lorage species (black oat -Avena sfrigosa Schereb. cv . Comum and yellow oat - A. byzantina Koch. cv. Coronado) - were evaluated iii a greenhouse bial at Faculty ol Agronomy UFRGS -, utiiizing a Hydromorphic Laterifu sou, steuiiized at 110°C for one hour for lhree days, and
reinocuiated with a soU microbial suspension fite of mycorrhizai fungi spores An additional treabnent with nonstehlized soil and without phosphate fehlizaon and mycorrhizai inoculation was used. The inoculation of VAM promoved a signuficative increment (P < 0.05) on the DM yield, conceniration and P uptake by oat
species. The mycorrhizai elfect were improved by lhe phosphate ferlilization. The best resulta were obsetved with lhe applicalion of tiple superphosphate on the levei 60 kg of P 205/ha. O. macrocarpum was more efticient than native VAM lungi. The yellow oat showed lhe greatest RMD, independently ol P source. The root colontzation and lhe number ol spores were increased by lhe VAM inoculation, mainly with yellow oat cultivation. The P application alfected negatively these parameters, atthe highest levei (60kg of P 205/ha). The inverse was observed with application ol rock phosphate