Teknologi formulasi pupuk hayati rizobakteria dan aplikasinya sebagai pemacu pertumbuhan tanaman kedelai dan biofungisida pada tanah masam

Abstract

Soybean production in Indonesia is still low, therefore Indonesian government must import soybean from other countries up to 45-50% to fulfill national requirement. This is a problem that should be solved through many approaches. One of the approach to increase soybean production through the use of plant growth promoting rhizobacteria (PGPR) that have been understood important in plant health and fitness. Our previous study resulted several indigenous strains of Pseudomonas sp. and Bacillus sp. from soybean rhizosphere that are combined with nitrogen-fixing bacteria Bradyrhizobium japonicum from soybean plant. The combinations of these bacteria were potential as plant growth promoter and biocontrol for root phytopathogenic fungi (biofungicide). For further use of these rhizobacteria, need to be developed bioprocess technology for formulation of inoculants production to increase soybean productivity. Objective of this research was to made biofertilizer containing rhizobacteria to be applied on soybean in acid soils. This research was conducted in 3 stages; optimalization media production in laboratory, formulation and bioassay in the greenhouse. The best medium for inoculants production are skim milk and molasses that produce bacterial population of 108-109 cfu/ml. Peat and talcum powder were used to formulation as carrier material. Three kind of prototype were produced; there were M-Sr (isolate Cr24, Crb17 dan Bj11); M-Rs (isolate Cr55, Crb64 dan Bj11); dan M-Fo (isolate Cr76, Crb86 dan Bj11). Each inoculant formed to three forms of formulations; there were granules (G), talc powder (T) and peat powder (S). Greenhouse test showed that several combinations of bacteria in the formula can stimulate the height of soybean plant, root weight, and plant performance. The biofertilizer applied with doses 400 g/ha for talc powder and peat powder. Rhizobakteria inoculants can be used as biofungicide. Disease suppression on Sclerotium roflsii, Rhizoctonia solani and Fusarium oxysporum respectively 79.98%, 27.27%, 50.12%. Storage up to 6 months was still able to maintain the bacterial population to 107-108 cells/g. Based on this result, we will asses this formula in field experiments under acid soils.