Productivity of direct seeded rice-wheat system as influenced by phosphorus levels and phosphate solubilizing bacteria

Phosphorus (P) is an important macronutrient required for the growth and development of crop plants. However, the majority of P in soil is present in insoluble forms. Phosphate solubilizing bacteria (PSB) has the capacity to convert insoluble phosphates into a form which is readily available to crop plants. Thus, the present investigation was conducted during rabi 2015-17 and kharif 2016-17 to investigate the effect of PSB and its inoculation methods (seed and/or soil) on productivity of direct seeded rice (DSR) -wheat system under varying P levels. For both the crops, improved growth and yield parameters were observed with the application of 60 kg P₂O₅/ha (P₆₀) followed by P₄₅ (45 kg P₂O₅/ha), P₃₀ (30 kg P₂O₅/ha) and control (no P). P₆₀ level of phosphorous resulted in significantly higher grain and straw yield for both wheat and DSR during both the years, which was statistically similar with P₄₅, but significantly better than P₃₀ and control. Although, no significant influence of PSB inoculations on yield and yield components of DSR and wheat were observed, but single (seed/soil) and mixed inoculation (seed+soil) of both the PSB strains (Bacillus spp. and PSB IARI) not only improved the grain yield and yield components but also increased the availability of soil nutrients (N, P and K), as compared to non-inoculated control plots. Application of PSB strains needs special emphasis for increasing production and productivity of DSR-wheat cropping system.