Influence of Integrated Nitrogen-Management and Poultry Manure on Growth Analysis and Yield Responses of Maize (Zea mays) Cultivated in Relay with Pumpkin and Cowpea

The ultimate aimed of any agricultural research program is to enhance the productivity of the test crop thereby ensuring food security for the populace. The research was carried out in the research and teaching field of the Institute for Agricultural Research, Samaru, Zaria during the 2019, 2020 and 2022 wet season. The treatments consist of three rates of poultry manure (0, 3 and 6 t ha-1), and two ways of split N application to maize (three split dose and two split dose) replicated four times. Maize and pumpkin were sown same day whereas, cowpea was relayed at 10 Weeks after sowing (WAS) following the harvesting of pumpkin. Result showed that the expression of growth attributes peaked at 10 WAS with the application of poultry manure at 6 t ha-1 producing the tallest plant, higher shoot dry matter and leaf area index (LAI). Crop physiological attributes such as Crop Growth Ratio (CGR), Relative Growth Ratio (RGR), and Net Assimilation Ratio (NAR) were significantly influenced by poultry manure with 3 t ha-1 rates of application having higher values. The highest grain yield of maize was obtained with the application of 3 and 6 t ha-1 which gave statistically similar average yield of 5115 and 5146 kg ha-1 respectively. Triple N dose application contributed to 19% increase in yield over double dose application, although not significant. In a general note, among the growth parameters, application of N in three split dosage influences plant height at 8 and 10 WAS; contributing 14.93% increase in plant height over the control, shoot dry matter and LAI. Result indicates that application of 6 t ha-1 of poultry manure and triple split application of 45 kg ha-1 of nitrogen enhances growth attributes of maize such as plant height, shoot dry matter and LAI, but did not translate into higher grain yield of maize. Summarily, for higher grain yield of maize, application of 3 t ha-1 of poultry manure together with 45 kg ha-1 of N fertilizer applied in two (2) split is recommended. Whereas, if the target is for increased vegetative growth, 6 t ha-1 of poultry manure with triple split application of 45 kg ha-1 of nitrogen in Urea form is recommended.