Effect of plant population, time of second dose of nitrogen fertilizer application on growth and yield of maize (Zea mays L.) varieties in Northern Guinea Savannah of Nigeria

The Study was conducted during 2023/2024 cropping season at Institute for Agricultural Research IAR, A.B.U., Samaru- Zaria (11011’N 07038E and 686m above sea level) and College of Agriculture and Animal Science, Irrigation Farm Mando, Kaduna (Lat 10o43’N, Long 06o34’E 500m above sea level) both located in the Northern Guinea Savannah Ecological Zone of Nigeria respectively, to evaluate the effect of plant population and time of nitrogen second dose fertilizer application on growth and yield of maize varieties in Nigerian savannah. Treatments consisted of Three maize varieties; SAMMAZ 15, SAMMAZ 16, and SAMMAZ 17, three plant population; P1 (40,000 p ha-1 ), P2 (60,000 p ha-1 ) and P3 (80,000 p ha-1 ) and five times of nitrogen second dose application; 4, 5, 6, 7 and 8 weeks after sowing (WAS). Treatments were factorially combined in a randomized complete block design (RCBD) and replicated three times. Data on growth parameters were collected on plant height (cm), number of leaves, leaf Area index (LAI), crop growth rate (CGR), Relative Growth Rate (RGR), and dry matter weight (g), while the yield parameter collected was grain yield kg ha-1 . Results showed that 2 plants stand-1had the best performance on both growth and gave the highest maize grain yield kg ha-1 , followed by 1 and 3 plants stand-1 respectively. Second dose of nitrogen application at 6 WAS resulted in higher growth attributes and gave the highest grain yield kg ha-1 and SAMMAZ 16 outperformed the other varieties in terms of growth attributes and gave the highest grain yield in kg ha-1 . The study suggests that farmers should adopt a plant population of P2 (60,000) plants ha-1 in combination with time of nitrogen second dose application at 6 WAS with SAMMAZ 16 for better performance on growth and yield of maize in the Agro-ecological zone