Nitrogen-management strategy through leaf-colour chart and SPAD meter for optimizing the productivity in irrigated wheat (Triticum aestivum)

A field experiment was conducted during the winter (rabi) season of 2020–21 at Bihar Agricultural University, Sabour, Bhagalpur, to study the effect leaf-colour chart (LCC) and SPAD meter on productivity of irrigated wheat (Triticum aestivum L.). The experiment, having 8 treatments, was laid out in a randomized block design. The first 4 treatments (T1 to T4 ) were LCC-based, T5 and T6 were the SPAD meter-based management practices and T7 was considered as fixed-time N management (FTNM) and T8 was kept as control where no N was applied. The SPADbased treatments T5 and T6 received 140 kg N/ha which was higher than all the other N management treatments resulted 13% higher ears/m2 and 18% higher grains/ear over the LCC-based N-management treatments. Among the LCC-based practice, treatment T4 recorded significantly highest grain yield (4.01 t/ha) but was lower (10.4%) than that of grain yield achieved in T5 treatment. The LCC-based treatments T1 to T3 though received a lower dose of N fertilizer (19%; average of T1 to T3 ) compared to the FTNM (T7 ), returns maintained the similar yield components with the FTNM. Therefore, use of farmers’ friendly and cost-effective tool LCC is very useful which saved the N fertilizer (19%) without hampering the yield components. Thus, LCC and SPAD may be effective tool for efficient need-based fertilizer N management using LCC and SPAD meter in improving crop growth for higher productivity in rational manner.