Comparative efficacy of phosphorous supplements with phosphate solubilizing bacteria for optimizing wheat yield in calcareous soils

Abstract

Phosphorus (P) deficiency is the main hurdle in achieving sustainable crop production ps especially in calcareous soils. Using bio-fertilizers like phosphate solubilizing bacteria (PSB) could be a useful approach for sustainable P management as they improve P availability in soil via dissolution, desorption and mineralization reactions. In addition, application of organic amendments with PSB could further ameliorate soil conditions for sustainable management of immobilized nutrients in calcarious soils. Therefore, we performed pot experiment to study the role of PSB in nullifying antagonistic effects of liming (4.78, 10, 15 and 20%) on P availability from poultry manure (PM), farm yard manure (FYM), single super phosphate (SSP) and rock phosphate (RP) in alkaline soils. PSB inoculation improved wheat growth, P availability and stimulated soil acidification over control regardless of P sources and lime levels. Soil calcification adversely affected plant growth, P nutrition, induced soil salinity and alkalinity, however, PSB and manures application potentially nullified such harmful effects over mentioned traits. Individually, organic sources were superior than mineral sources however, the performance of mineral fertilizers with PSB was at par to sole application of manures. Furthermore, application of RP with PSB proved as effective as sole SSP. Therefore, using PSB as bio-fertilizer has huge potential for improving P availability in calcareous soils.

Figure 1

Interactive effect of lime and P sources on plant height per pot. Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 2

Interactive effect of lime and PSB on wheat 100 grains weight. Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 3

Interactive effect of lime and PSB on wheat tillers per plant. Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 4

Interactive effect of lime and P sources on plant height. Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 5

Interactive effect of P sources and PSB on wheat grains per spike. Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 6

Interactive effect of lime and PSB on grain yield (g pot⁻¹). Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 7

Interactive effect of lime and P sources on grain yield (g pot⁻¹). Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 8

Interactive effect of P sources and PSB on wheat biological yield (g pot⁻¹). Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 9

Interactive effect of PSB and P sources on root biomass (g). Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 10

Plant P uptake (mg kg⁻¹) affected by lime and PSB. Errors bar represent standard error for the mean of three values. Graph bars sharing letters are statistically comparable at p ≤ 0.01.

Figure 11

Plant P uptake (mg kg⁻¹) as affected by the interaction of P sources and Lime. Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 12

Soil post-harvest P (mg kg⁻¹) as affected by P sources and Lime. Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 13

Interactive effect of PSB and P sources on plant P concentration (%).Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 14

Interactive effect of PSB and P sources on wheat P uptake (mg kg⁻¹). Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.

Figure 15

Post-harvest Soil organic matter (%) as affected by interaction of P sources and lime. Graph bars having different letters are significantly different at α = 0.05. Errors bar represent standard error for the mean of three values.