Evaluating biochar’s potential to reduce nitrate leaching and enhance wheat (Triticum aestivum L.) yield under different nitrogen management practices

Nitrate (NO₃-) leaching from alkaline coarse-textured agricultural soils is a major concern that reduces nitrogen use efficiency (NUE) and limits crop productivity. Application of biochar has been found to improve soil fertility through nutrient retention when used with nitrogen fertilizer, however, its efficacy in coarse-textured alkaline soil is insufficiently explored. A greenhouse pot experiment was carried out comprising completely randomized design (CRD) with five treatments and three replicates (15 pots) to investigate the effects of biochar applied with N doses on NO3- leaching, N uptake and wheat yield. The treatments consisted of T1 (Control), T2 (Nitrogen 75 kg ha-1), T3 (Nitrogen 150 kg ha-1), T4 (2% biochar + Nitrogen 75 kg ha-1), and T5 (2% biochar + Nitrogen 150 kg ha-1). Biochar application had significantly reduced NO3- leaching compared to no biochar with T4 and T5 showing the lowest levels of NO3- losses. All the biochar applied treatments produced high grain yield, N uptake, and improved NUE in terms of treatments with no biochar applied. The decrease in NO₃- leaching was coupled with increased N retention in the soil and enhanced plant growth parameters. This research indicates that 2% biochar with 150 kg N ha-1 is the most effective treatment to ensure maximum wheat production and reduces NO₃-- leaching in alkaline coarse-textured soils.