Growth indices, photosynthetic parameters and productivity of barley (Hordeum vulgare) as influenced by sowing dates and cutting management

Abstract

A field experiment was conducted during the winter (rabi) seasons of 2015–16 and 2016–17 at the Punjab Agricultural University, Ludhiana, to study the effect of staggered sowing on growth indices, photosynthetic parameters and productivity of barley (Hordeum vulgare L.) in relation to different cutting management. The experiment was laid out in a split-plot design with 3 sowing dates, viz. 15 October, 30 October and 15 November in main plots and 5 cutting management, viz. un-cut (control), cut at 50 days after sowing (DAS), cut at 60 DAS, cut at 50 DAS + additional 15 kg N/ha after cut (N₁₅) and cut at 60 DAS + additional 15 kg N/ha after cut (N₁₅)] in subplots, replicated 4 times. The results indicated that, the crop sown on 15 October registered the highest values of absolute growth rate (AGR) and crop growth rate (CGR) up to 120 days of crop-growth. Thereafter, crop sown on 15 November showed higher AGR and CGR values than that sown on 15 October and 30 October. Relative growth rate (RGR) was the highest in the crop sown on 15 October up to 30 days; 30 October up to 120 days and 15 November thereafter. Fodder cut at 50 DAS and cut at 50 DAS + N₁₅ treatments resulted in the negative values of AGR, CGR and RGR during 30–60 DAS. Transpiration rate and stomatal conductance decreased significantly and progressively with each delay in sowing. Uncut crop recorded the highest transpiration rate (0.53 m mol/m²/sec), whereas the crop cut at 60 DAS resulted in the lowest transpiration rate (0.26 m mol/m² /sec). Crop sown on 15 October resulted in 11.9 and 47.9% more grain yield and 18.3 and 25.2% more fodder yield than that sown on 30 October and 15 November, respectively. Control and cutting for fodder at 50 DAS gave similar grain yields, but were significantly higher than the other cutting-management treatments.