Efficiency of Glomus aggregatum, azotobacter, azospirillum and chemical fertilizer on growth and yield of single cross hybrid 4452 maize.

The efficiency of arbuscular-mycorrhizal fungi (Glomus aggregatum), azotobacter (Azotobacter chroococcum), azospirillum (Azospirillum lipoferum) and chemical fertilizer on the growth and yield of single cross hybrid 4452 maize was evaluated at the laboratory of the Soil Science Department, Faculty of Agriculture, Kasetsart University at Kamphaeng Saen campus and in a field experiment at the National Corn and Sorghum Research Center in Nakhon Ratchasima province. Pellets of arbuscular-mycorrhizal inoculum containing 30-50 spore/g and inoculum of azotobacter and azospirillum in granular form were produced using fine compost as a carrier having 10 7 -10 8 cfu/g in the population. The results revealed that corn growth in terms of plant height was greater for the microbially inoculated and fertilizer treatments than the control. The quantity of mycorrhizal spores in the mycorrhizal treatment was higher than in the other treatments. The rhizosphere of the soil used was suitable for azotobacter, with more than 10 6 cfu/ g found. The nitrogen, phosphorus and potassium contents of microbial-inoculated plants that had been subjected to chemical fertilizer treatment were greater than in the control. The difference among treatments of the residual soil nitrogen after harvest was not significant. The grain yield from the greenhouse experiment produced interesting results. The minimum yield found in the control treatment was 49.80 g/plant, while those of the microbial-inoculated treatments were higher. The yield of the azotobacter+azospirillum, azotobacter+arbuscular-mycorrhizalfungi+chemical-fertilizer and the azotobacter+chemical-fertilizer showed the greater yields, with 216.72, 211.32 and 198.42 g/plant, respectively, compared with 174.72 g/plant from the maize treated with chemical fertilizer. The grain yield from field experiment using azotobacter+chemical-fertilizer was the greatest (706.25 kg/ha). The sole application of arbuscular-mycorrhhizal inoculation gave a grain yield as high as that of the chemical fertilizer treatment (5,993.75.0 and 5,825.00 kg/ha, respectively). The yield of azotobacter+azospirillum+arbuscular-mychorrhizal-fungi+chemical fertilizer was 5,987.50 kg/ ha and the lowest yield was found in the control (3,543.25.0 kg/ha).