Impact of sodium and iron levels on yield, nutrient content and uptake by cowpea (Vigna unguiculata L.)

A pot experiment was conducted to see the effect of sodicity and iron levels on cowpea. Four levels of sodium adsorption ratio (SAR) 10, 15, 20, 25 and iron (Fe) control, 5, 10, 15 and 20 kg Fe ha⁻¹) were tested in completely randomized design with three replications. The results indicated that application of soil sodicity having SAR 15 recorded the maximum yield, phosphorus and potassium content and uptake and nitrogen uptake of cowpea over rest of the treatments. Application of Fe 20 kg ha⁻¹ recorded the maximum and significantly higher yield, nitrogen, phosphorus and potassium content and uptake of cowpea over rest of the treatments. Among the treatment combinations combined application of SAR 15 with Fe @ +20 FeSo₄.7H₂O) proved superior in all these parameters over other treatments.