Yield of wheat (Triticum aestivum) with reduced tillage and real time nitrogen management under Tarai-Bhabar region of Uttarakhand

An experiment was carried out during 2002–03 at G.B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand) for calibration of leaf color chart (LCC) for nitrogen topdressing in zero tillage wheat under different N management methods. The highest grain yield of wheat was recorded at 180 kg N ha⁻¹ (30 kg N ha⁻¹ basal + LCC based five topdressings @ 30 kg N ha⁻¹ each), which however, was at par with the LCC based treatment receiving 135 kg N ha⁻¹ (50 kg N ha⁻¹ basal + LCC based topdressings at crown root initiation (CRI) and jointing stage and both these treatments were superior to the standard recommendation (150 kg N ha⁻¹). Use of LCC threshold value of 5.0 for deciding the time and amount of N top dress resulted in higher grain yield than the LCC threshold value of 4.0. Fertilizer N-use efficiency estimated by difference method was highest in the LCC based treatment at 135 kg N ha⁻¹ under zero tillage (12.96 kg grain kg⁻¹ applied N) and the standard recommendation showed the lowest fertilizer use efficiency. It was also better in bed planting system compared to conventional method of planting. The results indicated that about 15–30 kg N ha⁻¹ can be saved by following zero tillage and bed planting method compared to conventional method of planting. Similarly, use of LCC for deciding the time and quantity of fertilizer for topdressing saved about 15–30 kg N ha⁻¹.