Precision nitrogen management in wet direct seeded Sali rice through green seeker, leaf colour chart and nano nitrogen

Abstract

A field experiment was carried out at Instructional cum Research farm, Assam Agricultural University, Jorhat to study the performance of direct seeded sali rice under different nitrogen management practices viz., green seeker, leaf colour chart and nano nitrogen during kharif season of 2021. The experiment consisted of ten different nitrogen management techniques. The experiment was laid out in randomized block design (RBD) with three replications. The rice variety “Ranjit Sub1” was sown on 16 July, 2021 and harvested on 30th November, 2021.The results of the experiment revealed that application of 20 kg Nha-1 as basal + 15 kg ha-1 N through LCC when LCC ≤ 5 twice starting from 21 DAS + rest green seeker guided resulted in the highest physiological parameters, growth parameters in all growth stages, yield attributing parameters, grain yield (4.88 t ha-1) and straw yield (6.36t ha-1) and harvest index. Besides, 120 kg Nha-1 applied as per recommended method (60kg basal+ 30kg at active tillering + 30kg at PI) significantly influenced all the growth parameters at 30DAS. In terms economics, application of 20 kg N ha-1 as basal + 15 kg ha-1 N through LCC when LCC ≤ 5 twice starting from 21 DAS + rest green seeker guided resulted in the highest gross return of ₹ 1,34,420.83 ha-1, net return (₹ 89,824.43 ha-1) and B:C (2.01), followed by treatment consisted of application of 20 kg Nha-1 basal + 20 kg Nha-1at 21 DAS + green seeker guided with gross return (₹ 1,28,158.75 ha-1), net return (₹ 83,714.25 ha-1) and B:C (1.88). The study suggests that application of site-specific nitrogen management with the help of green seeker and leaf colour chart can increase the yield of direct seeded rice in the most economical way with efficient utilization of nutrient.