Potential Use of Cyanobacterial Bio-fertilizer on Growth of Tomato Yield Components and Nutritional Quality on Grown Soils Contrasting pH

Abstract

Soil fertlity loss is considered as the most important prblem in developing tropical countries.This is especially serious for the Ethiopia whose larger proportion of the land mass is highland and soil mining through continous cultivation is common. On the other hand, cost of inorganic fertilizer is expensive and used in small quantity thus contributing to less crop yield. Even when this is possible, continous use of the chemical fertilizers in agricultural production is seriuos enviromental concern. In this study, therefore, a series of two different experiments were conducted to assess growth of cyanobacterial strains under two different water sources and to comparatively evaluate the use of cyanobacterial biofertilizer on growth and biomass production, and on nutritional quality of tomato fruits grown under contrasting soil PH (soil from WCU  farm and Balesa  are 5.9 and 8 respectively). In experiment I, two N fixing cyanobateria (Anabaena spp.) strains (E-3 and E-6)  were evaluated in tap and river water  for their growth and N fixation capacity. The result showed that there were siginficant difference (P<0.001) between strains in growth performance in both water sources. Accordingly, E-3 was found higher in growth and performance best in both water sources. In experiment II, five treatments namely dry as well as liquid cyanobacteria biofertilizer, urea, compost and unfertilized (control) were employed on tomato plant and studied in a CRD. The total experimental unit of the this research  was the combination of two factors( soil type and fertlizer type), thus altogether making 10 treatments. Also, the residual effect of the cyanobacterial biofertilizer on soil fertlity has been assessed. Analysis of results indicated that there were significant difference among N sources on plant height, fruit number,number of flower and primary branches, beta carotene, plant Nitrogen (N), Phosphrous (P), Zinc (Zn) and Iron (Fe) contents of the tomato plant. As compared to the control treatment, the dried cyanobacteria resulted in increased value  in plant height,  primary branches, fruit number, in fruit weight per plant, shoot dry weight and number of flowers. In the same manner after harvesting dried cyanobacteria treatment resulted in more soil available phosphrus (Av.P), soil total Nitrogen (TN), while there were reduction in soil pH and soil EC. And also, analysis of nutrient content of plant revealed that the dried cyanobacteria treatments resulted in an increased value of nutrient content of plant (TN, phosphrus Zinc, Iron and fruit β carotene) over the control treatments. In almost all parameters studied, the tomato plants performed better on soil from WCU farm than in soil from Balesa farm soil showing inherent difference in fertility of the soils at these sites. Generally, plants showed better growth with application of cyanobacyeria bio-fertilizers than with urea fertilizer and compost, thus indicating the potential of cyanobacteria biofertilizer as having a postive effect on soil fertility and yield and nutritional quality of cultivated vegetables such as tomato plant.

Keywords: Cyanobacteria, N fixation,tomato, Growth parametrs and Yield components