Management of phosphorus (P) in acid soils is becoming more challenging in the anticipated scenario of potential phosphate crisis in agriculture, because the P-use and-recovery efficiencies (PUE and PRE) of existing P management methods are notoriously low in acid soils. This investigation reported a rhizosphere-based P management method for improving P nutrition of rice (Oryza sativa L.) seedlings at the time of transplantation in order to support better root growth on post transplantation. By performing two independent incubation experiments, the critical doses of orthophosphate and incubation duration for seedling root-dip (SRD) in single super phosphate (SSP) amended soil slurry (a sandy clay loam Inceptisol, pH 4.3) were found to be 112.5 mg P kg-1 soil and 10 h, respectively using the critical curve approach. In field experiments, the rhizosphere-based P method (SRD in soil slurry + phosphate solubilizing bacteria, PSB + rock phosphate, RP (30 kg P 2 O 5 ha-1) performed better than SSP broadcast as basal application (60 kg P 2 O 5 ha-1) in terms of more root volume and P uptake of shoot and root at 45 days after transplantation (DAT), higher P uptake and content in rice grain and straw, enhanced PUE and PRE, comparable grain yield and 50% reduction in P fertilizer input quantity. This rhizosphere based P management (SRD in soil slurry+PSB+RP) method may be vigorously exploited for managing P nutrition in transplanted rice grown in acid soils.

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A sustainable method of phosphorus (P) fertilizer application is needed to support crop production, due to the limited P reserves and negative environmental impact caused by excessive P application in agriculture. This study proposes a comparison of P management that enhance P nutrition of Chilli seedlings (variety: Arka Khyati) through seedling root-dipping (SRD) into P-enriched slurry (SSP-amended soil slurry; pH of 8.1), micro-dose placement (MDP; drill and place closer to plant root), and full dose placement by broadcasting (FD). In SRD method, seedlings were dipped in three different P concentrations (0, 50, and 100 mg P2O5 kg-1) for varying durations (0, ½, 1, 2, 3, and 4 hours) and then transplanted into pots, along with the MDP and FD treatments, resulting in 15 total treatments with 5 replications. The amount of P adhered to the seedling roots in the SRD treatments was 21 and 90 times lower than that P applied in MDP and FD treatments, respectively. The best performance in biomass production was observed in seedlings dipped in 100 mg P2O5 kg-1 for 2 hours in SRD, (dipping in higher concentrations with longer durations resulting in plant death). Overall, the comparison showed a 52%, 178%, and 293% increase in biomass production compared to the control for FD, MDP, and SRD, respectively. P-use and -recovery efficiency followed the same trend. Further multilocational trials are necessary to assess this method, and it is recommended to apply a reduced amount of P to maintain a balanced of native P in the soil.