Abstract
In this study, four maize varieties (SC10, SC122, TWC310, TWC352) were tested with nitrogen fertilizers at 90, 120 and 150 kg N/fad and plant densities of 24,000 and 30,000 plants/fad. Results showed that higher nitrogen levels significantly improved leaf area index (LAI), crop growth rate (CGR) and net assimilation rate (NAR) within 60-90 days, leading to increased grain per row, 100-grain weight and overall yield, as well as earlier tasseling and silking. Conversely, higher plant densities reduced LAI, CGR and NAR and increased competition, which decreased grain weight per row and yield. Among the varieties, SC10 and TWC310 outperformed SC122 and TWC352 in growth and yield, demonstrating varied responses to nitrogen and density.