NPK mediated improvement in biomass production, photosynthesis and Na+ regulation in Panicum antidotale under saline conditions.

Panicum antidotale is a promising grass species for use as fodder and forage using non-conventional agricultural practices. It was therefore grown using brackish water irrigation to determine the optimal spacing and fertilizer treatment required for sustainable growth, ion relations and photosynthesis. Planting distance of 1.5 ft(2) resulted in higher biomass yield. Composite NPK fertilizer (NPK120) @ 120 kg ha(-1) supported better plant growth rather than N, P, K individually or their various combinations (NP, NK, PK, NPK). Addition of fermented farmyard manure (NPK120+FM) improved ion regulation (lower Na+ uptake, higher K+/Na+ ratio), photosynthetic rates and water use efficiency but did not improve biomass production compared to NPK120. However, higher Na+ uptake with NPK120 would result in lower ion accumulation in the root zone and delayed soil degradation. We conclude that NPK120 could support sustainable growth of Panicum antidotale in our cropping system by keeping leaf Na+ within safe limits for CO2 assimilation and reducing the need for frequent re-planting of salinized root stock.