Effects of Combining Chemical Fertilizer and Three Different Sources of Organic Manure on the Growth and Yield of Maize in Sub-Sahelian Savanna, Nigeria
Jacob M. Wapa, J. D. Kwari, S. A. Ibrahim

Agriculture in the sub-Sahelian savanna of Nigeria is characterized by low productivity due to decline in soil fertility. This is mainly attributed to the mining of nutrients due to continuous cropping without external addition of adequate nutrients coupled with low activity clay and kaolinitic mineralogy which promotes limited and inadequate land productivity. The adoption of combination of organic manure and chemical fertilizers is being taken as one of solutions to the situation. This study was carried out to investigate the effect of chemical fertilizer and three different sources of organic manure on some growth parameters and yield of maize. Field trials were carried out in 2008 and 2009 cropping seasons at the Teaching and Research Farm of the Department of Soil Science, University of Maiduguri, Maiduguri (11o 53’ N; 13o 16’ E). The treatments consisted of four levels of nitrogen fertilizers (0, 45, 60 and 90 kg N/ha) combined with three types of organic manures (cow dung, municipal wastes and poultry droppings) applied at three rates of each organic manure (0.0, 2.5, and 5.0 tons/ha). The experiment therefore contained twenty-eight (28) treatments laid out in factorial design and replicated three times in a randomized fashion. An extra-early variety of maize (SAMMAZ 28) was obtained from the Promoting Sustainable Agriculture in Borno State (PROSAB), Maiduguri. Plant height, number of leaves per plant, and leaf area were some of the growth parameters measured as well as grain yield in kg/ha. Plant height was not so much affected by the combination of chemical fertilizer and organic manure but chemical fertilizer levels alone significantly affected the plant height in 2008, 2009 and in the combined analysis. Leaf area was also significantly affected by chemical fertilizer levels in 2008, 2009 and in the combined analysis. Leaf area was also significantly affected by organic manure types in 2009 and in the combined analysis but not in 2008. Combining rates of nitrogen fertilizer (90 kg/ha N) with poultry droppings (5.0 tons/ha) gave the highest grain yield especially in 2008 (2466.7 kg/ha) and in the combined analysis (1883.7 kg/ha). It could be deduced that grain yield and yield parameters were significantly increased with the application chemical fertilizer (90 kg N/ha) in combination with cow dung and poultry droppings at the rate of 5.0 tons/ha. Chemical fertilizer rates of 60 or 90 kg/ha in combination with poultry manure or cow dung (5.0tons/ha) will give optimum yield of maize on the savanna soils.

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