Asian Journal of Soil Science and Plant Nutrition

A field experiment was conducted during (Kharif) seasons of 2023 at the Guru Kashi University, Talwandi Sabo, Bathinda, Punjab, to effect of different plant spacing and nitrogen levels on growth, productivity and available NPK of maize. The experiment was laid out in a split plot design with three replications, under three plant spacings of 45 cm x 15 cm, 55 cm x 20 cm, and 65 cm x 25 cm were included in the treatment plan, along with four nitrogen levels: control (75% of RDN (31.5 kg N/ha), 100% of RDN (42 kg N/ha), and 125% of RDN (52.5 kg N/ha). At every stage of the crop's growth, the leaf area index (LAI) with 125% of RDN was the highest and much better than that with 75% and 100% of RDN. Throughout the crop's growth stages, the spacing of 55 cm x 20 cm generated the least amount of dry matter. At a 45 cm X 15 cm spacing, the highest grain weight of 30.33 g was attained, which was comparable to the remaining plant spacing. At 55 cm X 20 cm, the lowest grain yield (52.76 q/ha^-1) was observed. With respect to nitrogen, highest harvest index (34.74%) was associated with application of 75% of RDN which was significantly superior over 100% of RDN With respect to plant spacing significantly highest harvest index (36.64%) was recorded at 45 cm X 15 cm and lowest harvest index (31.98%) was recorded with 65 cm X 25 cm and it was on par with 55 X 20 cm (33.24 %). With regard to plant spacing, higher soil available nitrogen and phosphorous was recorded at spacing of 65 cm X 25 cm, higher available potassium at spacing of 45 cm X 15 cm.