Abstract
Phosphorous (P) fertilization up to 60 kg ha−1 significantly increased grain and straw yields of wheat and P uptake while Zn removal improved up to 30 kg ha−1. Agronomic efficiency decreased up to 90 kg ha−1. P recovery was higher at 60 kg ha−1 (21.63%) while physiological efficiency (91.14 kg kg−1 P2O5) and value: cost ratio (VCR), i.e. 8.87 were higher at 30 kg P2O5 ha−1. Zinc fertilization up to 6 kg ha−1 also significantly enhanced grain and straw yields and P removal while Zn removal increased significantly up to 12 kg ha−1. Agronomic efficiency (115.3 kg kg−1 nutrient) and apparent Zn recovery (1.87%) were also higher at 6 kg Zn ha−1 while maximum physiological efficiency (6.84 kg g−1 Zn uptake) and VCR (3.21) were recorded at 3 kg ha−1. Productivity of wheat-pearl millet system and apparent P recovery were higher at 60 kg P2O5 ha−1 and 6 kg Zn ha−1. Increasing P and Zn levels resulted in decline in VCR of system. Availability of P in soil after harvest increased and Zn decreased significantly up to 90 kg P2O5 ha−1 while available P decreased and Zn increased significantly up to 12 kg Zn ha−1.