Abstract:
Heavy usage of chemical fertilizers creates
varieties of economic, environmental and ecological
problems. Bio-fertilizers are one of the alternative means
which include beneficial microorganisms to reduce
harmful effects to human and environment. Considering
this an experiment was conducted at the Rice Research
Station, Sammanthurai, Sri Lanka in the ‘Yala’ 2017
to assess the effects of chemical and bio-fertilizers on
plant height, Leaf Area Index, chlorophylls a, b and
total chlorophyll contents and yield of rice cultivar ‘Bg
250’. The treatments were T1 - No fertilizer (Control),
T2- 100% Recommended chemical fertilizer, T3-50%
Chemical fertilizer + 50% Bio-fertilizer, T4-50% Bio fertilizer, T5-100% Bio-fertilizer. Bio-fertilizer consisted
of Azotobacter chrocooccum, Azospirillum brasilense,
Bacillus polymyxa, Bacillus megaterium and other
Bacillus spp. in liquid based medium. The experiment
was laid out in the Randomized Complete Block Design
with five treatments and four replications. The application
of chemical and bio-fertilizers has significantly (p<0.05)
affected the tested growth parameters and yield of ‘Bg
250’ rice cultivar. The combined application of 50%
chemical and 50% bio-fertilizer has given the highest
plant height (58.2cm), the highest Leaf Area Index (2.5),
the highest chlorophyll contents (Chl. a - 1.7 mgg-1, Chl.
b-1.4 mgg-1 and total Chl. - 3.1 mgg-1) and yield (2500
kgha-1) compared to the other treatments. The control
treatment where no fertilizers were added showed the
lowest growth attributes and yield. Based on these results
it was concluded that the combined application of 50%
chemical and 50% bio-fertilizers has produced the highest
growth performance and yield in the rice cultivar ‘Bg
250’. It could therefore be stated that bio-fertilizer in
combination with chemical fertilizer could be used as an
alternative way in the production of rice to boost the yield
with reduced hazards to human health and environment.
