Optimizing maize production through sowing date, nitrogen levels, and cultivar selection in northwest region of India

Maize is the third largest growing cereal crop in Northwest India (Punjab) after wheat and rice, faces significant challenges posed by increasing temperature, changing rainfall patterns and nutrient deficiency. These challenges can be addressed and maize production can be improved by optimizing management practices, such as sowing date, nitrogen level and cultivar selection. The primary objective of this study was to evaluate the effects of sowing date, nitrogen levels and cultivar dynamics on the phenology, plant growth, biomass yield, grain yield, and associated yield-related characteristics of maize in Northwest India (Punjab). A field experiment was conducted in a split–split plot design (SSPD) with three replications, comprising twenty-four treatment combinations of sowing dates (SD1: May 25, SD2: June 4, SD3: June 14 and SD4: June 24), cultivars (PMH1 and PMH2) and nitrogen levels (NL1: recommended −25 kg, NL2: recommended and NL3: recommended +25 kg). The results showed that plant height, leaf area index, dry matter, biomass yield, grain yield and yield attributing characters were highest in sowing date SD1, cultivar PMH1 and nitrogen level NL3. The postponed sowing date from SD1 to SD4 resulted in a reduction of 14.18% in grain yield in 2020 and 13.66% in 2021. Compared to cultivar PMH2, the cultivar PMH1 produced higher grain yield of 5343.6 kg ha−1 in 2020 and 5615.8 kg ha−1 in 2021. Among the nitrogen levels, treatments with an additional 25 kg nitrogen (NL3) resulted in a significantly higher grain yield of 428.4 kg ha−1 in 2020 and 331.8 kg ha−1 in 2021, surpassing those observed under NL2; however, it reduced the grain yield in NL1 by 616.5 kg ha−1 in 2020 and 579.7 kg ha−1 in 2021 compared NL2. The finding suggests that early sowing (SD1), cultivar PMH1 and an additional 25 kg nitrogen (NL3) can lead to higher grain yield, while postponed sowing (SD4) and lower nitrogen level (NL1) can result in reduced grain yield.