Resumo

LOPEZ, Marisol et al. Bacterial biofertilizers effect on the growth of a maize cultivar in two venezuelans contrasting soils ¹. Agronomía Trop. [online]. 2008, vol.58, n.4, pp.391-401. ISSN 0002-192X.

The effect of native strains of associative nitrogen-fixing (NF) and phosphorus-solubilizing (PS) bacterias on the growth of maize cultivar INIA-SQ-1, was evaluated in greenhouse experiments, in an Haplusterts soil of high fertility (Soil A) and a Typic Paleustults soil of low fertility (Soil B). We evaluated eight treatments: T1: 0N + 100%P +100% K; T2: 100% N +100% P + 100%K; T3: 70% N+100% P+100% K + strain of NF; T4: 70% N +50%P +100%K + strain of NF + strain of PS; T5: 100% N + 0 P +100% K ; T6: 100% N + 50% P+100% K+ strain of PS; T7: 100% N total+ 0P+100% K + strain of PS; T8: 0N + 0P + 0K, where the percentages in each treatment represent the proportion of the nutrient recommended in each soil in accordance with its fertility. The biofertilizers doses were 50 ml/pot of NF and PS respectivelly. In the soil A the NF strain acted as an emergence promoting rizobacterial: in this soil there was 30 and 24% more germination and plants with the first true leaf at the 6 days than in the soil B. The plant high, stem diameter, leaf long and wide, root and aereal biomass showed the effectiveness of NF in both soils, and the effectiveness of PS in the soil B. The effect of NF and PS on Plant Growing Promoting Rhizobacterial (PGPR) was demonstrated in the soil B. The content  of N and P in plant tisssue confirmed the results.

Palavras-chave : Biofertilizers; Zea mays; soil; fertility; Azotobacter; B. megatherium.