Abstract:
At present, Sri Lanka imports phosphorus fertilizers incurring a lot
of foreign exchange even though there is a high-quality apatite
deposit at Eppawala. Eppawala rock phosphate (ERP) can be
utilized as a Phosphorus fertilizer having increased the water
solubility of rock phosphate through chemical or biological
processes. However, biological processes are more cost-effective
and ecofriendly. Thus, the study focused to increase the solubility of
ERP using the selected soil microbes. Soil samples which contain
different microbes were collected using a simple random sampling
method (n-30) from five forested areas (Badagamuwa, Sinharaja,
Diyathalawa Turpentine, Girandurukotte Teak, and Nonperial Pinus
plantations) considering the phosphorus level in the soil,
distribution in Sri Lanka, and microbial count in the soil. Microbial
rich cultures were prepared by using the obtained soil samples and
applied to the ERP. A randomized complete block design (RCBD)
was used for the experiment with 5 replicates for each treatment
and only ERP was used as a control. Treated samples were tested
for the available phosphorus percentage using the Ascorbic acid
method during 8 weeks within a week interval. The results were
statistically analyzed using two-way ANOVA and Tukey pairwise
comparison test (95% confidence interval). The available
phosphorus percentages of all treated samples were significantly
higher (p<0.05) than the controlled samples in every week. The
highest available phosphorus percentages of all treated ERP
samples were in 0.75% - 0.81% range while controlled (ERP) was
0.42%, which significantly recorded (p<0.05) in 6th week. Selected
soil microbial cultures increased the solubility of ERP and therefore
ERP can be utilized as a phosphorus fertilizer with applying the
further improved microbial cultures
