Productivity, nutrient uptake and economics of wheat (Triticum aestivum) under potassium and zinc nutrition

A field experiment was conducted during the winter (rabi) seasons of 2010–11 and 2011–12 at Bichpuri, Agra, Uttar Pradesh on sandy-loam soil, to assess the effect of potassium and zinc nutrition on wheat [Triticum aestivum (L.) emend. Fiori & Paol]. Treatments comprising 4 levels each of K (0, 30, 60 and 90 kg K₂O/ha) and Zn (0, 3, 6 and 9 kg/ha) were evaluated in randomized complete-block design with 3 replications. Growth and yield parameters of wheat increased significantly with the increasing levels of K up to 60 kg K₂O/ha which were statistically at par with 90 kg K₂O/ha. The mean grain (5.31 t/ha) and straw yields (9.80 t/ha) with 60 kg K₂O/ha were 15.4 and 13.7% higher than the control, respectively. Application of 60 kg K₂O/ha resulted in significantly highest net returns (48.1 × 10³/ha) and benefit: cost ratio (1.90). Increasing zinc levels up to 6 kg Zn/ha showed significant improvement in plant height, effective tillers, grains/spike and 1, 000-grain weight over the control. Similarly, application of 6 kg Zn/ha resulted in 8.8% higher grain yield (5.22 t/ha) than the yield obtained in the control (4.80 t/ha). Significantly highest net returns (47.8 × 10³/ha) and benefit: cost ratios (1.95) were recorded at 6 kg Zn/ha. Uptake of N, P, K, S and Zn in wheat crop increased significantly with increasing levels of potassium. Protein content and yield in wheat grain increased significantly with the addition of K₂O up to 90 kg/ha and Zn up to 9 kg/ha. The nutrient uptake (N, K and Zn) in wheat, except those of P and S, increased significantly up to 6 kg Zn/ha. The efficiency indices decreased at higher doses of K and Zn and the maximum values were recorded at 60 kg K₂O/ha and 6 kg Zn/ha.