Comparative Effectiveness of Zeolite- and Biochar-Coated Urea Formulations with Nitrogen Dose Optimization for Enhanced Wheat Productivity and Nitrogen Use Efficiency

<title>Abstract</title> <p> In wheat (Triticum aestivumL.), conventional urea has low nitrogen use efficiency (NUE) because of high rate of N loss, which compromises productivity and environmental sustainability. The use of natural coating materials in controlled-release fertilizers (CRFs) is a promising approach to synchronizing N release with crop demand. But there were still few natural coatings that have been evaluated against each other in similar conditions with systematic optimization of the coating doses. The pot experiment was carried out in a completely randomized design (CRD) with factorial design. Four types of fertilizers were tested: conventional urea (CU), neem coated urea (NCU), biochar coated urea (BCU) and zeolite based coated urea (ZBCU) with three doses of N (50%, 75% and 100% of recommended dose) of 800 mg N pot ^-1 or ~240 kg N ha ^-1 . Growth parameters (stem length, leaf area index, tiller number, chlorophyll content), yield components (grains per spike, 1000-grain weight, fresh and dry biomass, grain yield and harvest index), and N use efficiency indices were measured. The data were subjected to two-way analysis of variance (ANOVA) and Duncan's New Multiple Range Test (DMRT) was used for separating treatment means at p ≤ 0.05. All the coated urea formulations significantly (p &lt; 0.001) improved all the growth parameters, physiological traits and yield components in comparison to CU. ZBCU had the highest values for most of the parameters measured. The maximum stem length (64 cm), fresh weight (62 g pot ^-1 ), dry weight (23.2 g pot ^-1 ) and 100-grain weight (6.25 g) were recorded under ZBCU at 100% N. Critically, applying ZBCU at 75% N and BCU at 75% N yielded grain yields statistically identical to CU at 100% N, indicating a potential of saving 25% N application without any yield penalty. Under condition of BCU, the chlorophyll content (SPAD value) was the highest (52.4) followed by CU (46.8). The PFP _N of nitrogen (PFP _N ) varied from 18–27% higher in the coated formulations and the highest was recorded at lower rates of N application. The use of zeolite and biochar coated urea significantly boosts wheat productivity, NUE and allows a reduction in Nitrogen application by 25% without affecting the yield. The semi-arid wheat production systems will benefit from an economically and environmentally viable N management strategy using 75% of the recommended N dose in the form of ZBCU or BCU. </p>