Integrated Application of Mineral Nitrogen and Cattle Manure to Improve Nitrogen Use Efficiency and Grain Yield of Maize

摘要

Field experiments were conducted at the Plantation Crops Section of Kwame Nkrumah University of Science and Technology in Kumasi, Ghana in 2014 major and minor seasons to study the effect of combining mineral nitrogen at different application times with cattle manure on nitrogen use efficiency and grain yield of maize. The experiments were factorial in randomized complete block design with four replications. The factors were cattle manure at the rates of 0, 2, 4 and 6 tons/ha; and nitrogen application times as follows: 50% N at 2 weeks after planting and 50% at 4 WAP (NT1), 50% N at 2 WAP and 50% at 6 WAP (NT2), 50% N at 2 WAP and 50% at 8 WAP (NT3) and a control (0 kg N/ha). Results showed that NT2 application increased the nitrogen use efficiency in major and minor seasons more than other application times. The nitrogen use efficiency increased with increase in manure rate, but at a diminishing return. Grain yield was also higher at NT2 and also increased with increase in manure rate. Application of mineral nitrogen at NT2 along with 6 tons/ha cattle manure rate was, therefore, considered best combination for increasing yield of maize in the country.