Glycine–Glomus–Phosphate Solubilizing Bacteria Interactions Lead to Fertilizer Phosphorus Economy in Soybean in a Himalayan Acid Alfisol

Abstract

Effects of Glycine–Glomus–phosphate solubilizing bacteria (PSB) interactions were studied on productivity, nutrient dynamics, and root colonization in soybean in a phosphorus (P)–deficient Himalayan acidic Alfisol in a greenhouse experiment. Treatments consisted of three vesicular arbuscular mycorrhizae (VAM) cultures, VAML [VAM culture, Glomus mosseae, developed by CSK Himachal Pradesh Agricultural University, Palampur, India], VAMT [VAM culture, Glomus intraradices, developed by Centre for Mycorrhizal Research, The Energy and Resources Institute (TERI), New Delhi, India], and VAMI [VAM culture, Glomus mosseae, developed by Indian Agricultural Research Institute (IARI), New Delhi, India], and a local PSB culture (Pseudomonas striata) alone or in combination with or without 75% of recommended phosphorus pentoxide (P2O5) dose based on targeted yield concept following the soil-test crop response (STCR) precision model. Sole application of PSB or either of the above VAM cultures considerably enhanced VA-mycorrhizal root colonization and root weight besides crop productivity and nutrient uptake over control. A similar stimulatory effect with significant enhancement on mycorrhizal root colonization and root weight was observed with coinoculation of PSB and VAM cultures over the control. Dual inoculation of VAM and PSB cultures also resulted in significant improvement in grain and straw yield besides grain protein content, thereby revealing a synergistic interaction between VAM and PSB. Coinoculation with either of VAMT (Glomus intraradices) or VAMI (Glomus mosseae) + PSB + 75% P2O5 dose remained at par with sole application of 100% P2O5 dose with respect to crop productivity, nutrient content, nutrient uptake, and soil fertility status besides the greatest root colonization and root weight at flowering, indicating that Glycine–Glomus–PSB interactions in combination with 75% P2O5 dose based on STCR precision model lead to economization of fertilizer P by about one-fourth without impairing crop productivity and soil fertility in soybean in a Himalayan acidic Alfisol.