Response of late-sown wheat (Triticum aestivum) to row spacing-cum-population densities and levels of nitrogen and irrigation in north-western Rajasthan

A field investigation was conducted during the winter (rabi) season of 1998-99 and 1999-2000, to find out the optimum row spacing-cum-population density, nitrogen and irrigation level requirement for late-sown wheat (Triticum aestivum L. emend. Fiori & Paol.). Narrow row spacing of 15 cm using 205 kg seed/ha resulted in significant higher grain yield (29.9 and 27.9 q/ha) compared with normally used spacing of 22 cm with 140 kg seed/ha. Significant increase in yield was recorded up to 150 kg N/ha and it did not differ significantly with that obtained with 180 kg N/ha. Irrigations at IW : CPE 0.8 with each irrigation of 6.0 cm, recorded significantly higher grain yield (29.5 and 27.6 q/ha) than that of irrigation at IW : CPE 0.6, but it was at par with that of irrigation at IW : CPE 1.0. Similarly, 150 or 180 kg N/ha recorded higher water use-efficiency (8.5 and 7.7 kg/ha-mm). Increase in irrigation levels decreased water-use efficiency. The highest water-use efficiency of 76.4 and 66.9 kg grain/ha-cm during 1998-99 and 1999-2000, respectively, was recorded with narrow spacing. Narrow row spacing recorded higher net return (Rs 11,729 and 101 56)/ha and benefit : cost ratio (2.2 and 2.0). Nitrogen levels of 150 kg/ha gave the highest net return (Rs 12, 203 and 10,678) and benefit : cost ratio followed by 180 kg and 120 kg N/ha. The highest net return and benefit: cost ratio were obtained with 6 cm irrigations applied at IW: CPE ratio 1.0 and IW: CPE ratio 0.8 in 1998-99 and 1999-2000, respectively, schedule for a wheat after a 10 cm pre-sowing irrigation. Interaction effect of spacing and nitrogen, nitrogen and irrigation and spacing and irrigation had significant effect on grain yield in both the years.