Potassium fertilization for enhancing yield attributes, yield and economics of wheat (Triticum aestivum)

A 2-year field experiment was conducted during the winter (rabi) seasons of 2015–16 and 2016–17 at New Delhi, to evaluate the effect of rate, method, time and source of potassium (K) fertilization on yield attributes, yield and economics of wheat (Triticum aestivum L.). Potassium supply enhanced the yield attributes (spike weight, spike length, grains/spike, fertility %) and yield (grain and straw) significantly. Application of 60 kg K₂O/ha in 2 splits, half basal and remaining half at spike-initiation stage or 75% basal and remaining 25% at spike-initiation stage increased the grain yield (5.5 t/ha), net returns ( 78, 000) and benefit: cost ratio (2.2) by 8.8, 9.5 and 10%, respectively over applying the entire dose as basal. A strong positive and significant correlation was observed between yield attributes (r² = 0.80–0.96) (total tillers/m², grains/spike, spike weight, spike length and fertility %) and grain yield. Two foliar sprays of 2.5% potassium nitrate increased fertility percentage by 5 and grain yield of wheat by 6% over the control. However, foliar spray of potassium nitrate was not beneficial if combined with split application of recommended dose of potassium (60 kg K₂O/ha), whereas foliar spray proved good substitute for topdressing of potassium. Basal application of 53.8 kg K₂O/ha followed by 2 foliar sprays of potassium nitrate, was equally beneficial to 2 split application of 60 kg K₂O/ha. Similarly, 2 split application of 60 kg K₂O/ha at 50: 50 or 75: 25 ratio increased the benefit: cost ratio by 10% (2.2) over application of entire dose as basal.