摘要：Nitrogen (N) and Phosphorus (P) deficiency is a major yield limiting factor across the globe and their proper management plays a vital role in optimizing crop yield. This field experiment was conducted to assess the impact of soil and plant nitrogen N and P ratio on the growth and yield of wheat (<i>Triticum aestivum</i> L.) in alkaline calcareous soil. The study consisted of various levels of nitrogen (0, 40, 80, and 160 kg ha<sup>−1</sup> as urea) and phosphorus (0, 30, 60, and 90 kg P<sub>2</sub>O<sub>5</sub> ha<sup>−1</sup> as diammonium phosphate), and was carried out in randomized complete block design (RCBD) with factorial arrangement having three replications. The result showed that the addition of 160 kg N ha<sup>−1</sup> significantly improved biological yield (10,052 kg ha<sup>−1</sup>), grain weight (3120 kg ha<sup>−1</sup>), chlorophyll content at tillering stage soil plant analysis development (SPAD) value (35.38), N uptake in straw (33.42 kg ha<sup>−1</sup>), and K uptake in straw (192 kg ha<sup>−1</sup>) compared to other N levels. In case of P, 90 kg P<sub>2</sub>O<sub>5</sub> ha<sup>−1</sup> had resulted maximum biological yield (9852 kg ha<sup>−1</sup>), grain yield (3663 kg ha<sup>−1</sup>), chlorophyll content at tillering stage (SPAD value 34.36), P (6.68 mg kg<sup>−1</sup>) and K (171 kg ha<sup>−1</sup>) uptake in straw. The sole use of N and P have positively influenced the biological and grain yield but their interaction didn’t response to biological yield. The present study reveals that SPAD value (chlorophyll meter) is the better choice for determining plant N and P concentrations to estimate the yield potential.
