Growth response of tomato (Lycopersicum esculentum Mill) inoculated with Azotobacter croococcum in an alfisol

Abstract

The performance of Azotobacter croococcum Beijerinck in enhancing growth and fruit production of tomato (Lycopersicum esculentum Mill) was investigated in 3 greenhouse experiments and a field study. The first experiment assessed the appropriate method of inoculation while the 2^nd study determined the relationship between increases in the volume of inoculum and the yield parameters. Experiment 3 investigated the required number of doses needed for optimum yield.. The field study attempted to validate positive responses obtained in the greenhouse. Seedling inoculation and urea application at 2 weeks after transplanting (WAT) led to increases ranging from 50% to over 160% in all the parameters assessed when compared with the un-inoculated and unfertilized control. The observed increases started from 6WAT. Soil and seed inoculation did not significantly (p=0.05) impact positively on the height, stem girth as well as the number of fruits of the test crop when compared with the control. There was a positive correlation between increase in inoculum rates and plant height and girth with the regression coefficient (r²) ranging from 0.74 to 0.96. Application of 2-3 doses of 50mls of the inoculum to the seedling enhanced plant height and stem girth especially from 6WAT. Application of 2 doses at 2weeks interval gave about 10% increase in the number of fruits over the 2 dose-application. In the field, no significant (p=0.05) differences were obtained in plant growth and yield when either the Azotobacter inoculum or urea was used. Each of the treatments however, increased the growth and fruit yield of tomato when compared with the control. Nitrogen fertilization promoted growth and yield of tomato. The use of Azotobacter croococcum inoculum was an effective biological management option in tomato fertilization programme.

Keywords: Azotobacter croococcum, growth, tomato, urea

Moor Journal of Agricultural Research Vol. 5(1) 2004: 13-18