Using of isolated blue-green algae from a paddy in Gillan province as a biofertilizer in rice plant)Oryza sativa)

Heterocystous blue-green algae (BGA) are group of nitrogen fixation free living microorganisms that grow naturally in paddy fields. In this research BGA population of one paddy in Gillan province in different seasons, were isolated, identified and added to rice and soaked seeds as a biofertilizer. In this examination pH and moisture of soil were measured. In another examination, 2g algae were added to rice pots and plant height and total weight, root length, moisture, bulk density, particle density and porosity of soil were surveyed. Anabaena was the only heterocystous BGA found in soil samples with four species: A. spiroides, A. osillarioides, A. torulosa and A. variabilis. The highest and lowest pH (6.7, Springer & 6.2, winter) and moisture of soil (43%, Springer & 36%, winter) was in spring and winter, respectively. In addition the highest of blue-green algae population in spring (20, 12 in A & B medium) and lowest in winter (5, 4 in A & B medium) were observed. Rice seeds soaked in water and BGA germinated earlier than control seeds and the height of seedlings and roots of treated seeds were more than seeds soaked in water after 20 days. The result of pot culture experiment were: 53% increase in plant height, %66 increase in Roots length, %58 increase in Weight of fresh leaf and stem, %80 increase in Weight of fresh root, %125 increase in Weight of dry leaf and stem, %150 increase in Weight of dry root of seedling grown in pots and %20 increase in Moisture and %9.8 decrease in Bulk density, %4.8 decrease in Particle density, %28 increase in Porosity of soil and there were significant differences in pot treated with BGA as compared with control.