Effects of Employing Biofertilizer and Combining It with Inorganic Fertilizer on Soil Available Phosphorous, Total Soil Microorganisms, and Productivity of Rice (Oryza sativa L.)

Abstract

There is a growing trend in agriculture to use Bacillus bacteria as biofertilizer. This is a result of the detrimental effects that inorganic fertilizers have on the agricultural environment. Despite this, the decreasing soil fertility makes inorganic fertilizer less effective in achieving the required crop productivity. In a study conducted at Bogor Agricultural University in Indonesia, the effects of Bacillus sp. Biofertilizer alone and in combination with NPK and UREA fertilizers were investigated on rice field. The experiment was a two-factor treatment arranged in a split plot design with three replications using a randomized complete block design (RCBD). The first factor was fertilizers as main plot. The second factor was paddy varieties as sub plot. We hypothesized combination of biofertilizer and inorganic fertilizer might improve productivity of rice field. The results showed that application of treatment NPK₃₀₀UREA₁₅₀BF₄ resulted to increase of soil available P of 12.04%, 40.69%, and 44.05% in comparison with treatments NPK₀UREA₀BF₀, NPK₃₀₀UREA₁₅₀BF₀, and NPK₀UREA₀BF₄ respectively. The same treatment resulted in increase of 28.13% and 13.64% of productive tillers per plant compared to NPK₀UREA₀BF₀ and application of NPK₃₀₀UREA₁₅₀BF₀ respectively. Moreover, applying the former treatment, resulted in increase of yield of 64.08% and 30.33% compared to NPK₀UREA₀BF₀ and NPK₃₀₀UREA₁₅₀BF₀ in Mekongga variety while in IPB 3S there was yield increase of 85.80% and 10.34% respectively. The application of treatment NPK₁₅₀UREA₇₅BF₄ resulted higher total soil microorganisms of 14.6×10⁶ (CFU). Overall, the results showed that combination of biofertilizer with inorganic fertilizers improved soil available P, total soil microorganisms, productivity of rice tillers, and paddy yield compared to a single fertilizer application.

keywords: Bacillus, indole-3-acetic acid, inorganic fertilizer, nitrogen fixation, phosphate solubilization, and root exudates.