Effects of biological and chemical phosphorus fertilizers on growth analysis of maize S.C. 704 with different irrigation regimes

In order to study the influence of various irrigation regimes (drought stress), biological fertilizers (a combination of two Phosphate-solubilizing microorganisms) and different amounts of phosphorus fertilizers on some physiological indices of maize SC 704, a factorial split plot design in a completely randomized block design (RCBD) was conducted with three replications at the research field of Aboureihan Campus- Tehran University, Iran. The main plots were three irrigation regimes including 75, 100 and 125 mm (accumulative daily evaporation from the cap class A). The subplots were considered to be a mixture of the biological fertilizers in two levels (applied and non-applied) with triple superphosphate fertilizer in four levels including 0, 75, 150 and 225 kg/ha on factorial basis. The trends in the leaf area index, crop growth rate and relative growth rate were studied. By deviation from the optimal moisture and nutritional condition, a decrease in leaf area was caused to reduce crop growth rate and total dry matter in sever stress conditions (12 mm evaporation from the cap) and non-application of biological and chemical fertilizers. The maximum leaf area index (LAI) was observed in normal conditions at anthesis phase (LAI= 5.7), while it was lower at sever stress conditions (LAI= 3.14). In 12 fully expanded leaf stage, a similar increasing trend was observed with respect to leaf area index by appling 150 and 225 kg/ha chemical fertilizer, and it was significantly different from non-application of fertilizer. When biological fertilizer was appllied alone, there were no significant differences in leaf area index.