Volume 6 No.9, September 2016 ISSN 2224-3577 International Journal of Science and Technology ©2016 IJST. All rights reserved http://www.ejournalofsciences.org Effect of Cowpea Residue Nitrogen on Maize Growth and Yield in the Semi- Deciduous Region of Ghana Fataah, J., J. Sarkodie-Addo Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Kumasi Ghana. ABSTRACT A field experiment was conducted in the minor season 2014 to study the residual N effect from 10 cowpea residues on maize production following incorporation of the residues into their respective plots. An additional maize plot was added to each block where no cowpea was grown in the major season and therefore no residue was incorporated. This plot received the normal recommended fertilizer rates and served as the control treatment. The experimental design was Randomized Complete Block with four replications. The maize variety, Abontem, an extra early maize was used. Data collected were stem girth, dry matter, mean seed weight, harvest index and total grain yield. The results showed that the Asetenapa residue incorporated plots recorded the greatest grain yield, though this was not significantly higher than the fertilizer applied treatment. All residue incorporated treatments produced grain yield similar to the fertilizer applied plot. The results indicate that if farmers would incorporate all cowpea residues after grain harvest into their fields, there would be no need to apply chemical fertilizer. This will definitely cut down production cost as well as reducing the menace of fertilizer application on the environment. 1. INTRODUCTION Maize is the most important cereal crop produced and consumed in Ghana [8, 2]. Maize accounts for more than 50 percent of the total cereal production in the country. The bulk of maize goes into consumption and is the most important crop for food security. The crop has now risen to a commercial status elsewhere on which many agro- based industries depend for raw materials [6]. According to [4], maize contains 80% carbohydrate, 10 percent protein, 3.5percent fiber and 2 percent mineral. It also contains vitamin B and iron. According to [7], maize has a variety of uses. The starch extracted from the grain is used in making confectionary and noodles. Maize can be used as forage, feed for livestock and for making silage after fermentation of corn stocks. The crop is a multipurpose crop because every part of it has economic values. The grain, leaves, stalk, tassel and cob can be used to produce a large variety of food and non- food products [5]. For the varied importance of maize, production needs to be increased to satisfy its demand by the increasing population. Farmers are obliged to the use of artificial fertilizers to increase production which has its own implications such as high cost of production and environmental pollution. Cowpea, like all legumes are known to fix N from the air for their own use and leave some N in their residues for subsequent crops. The latter ability must be investigated and verified if the residual N can support economic growth and yield of maize since most peasant farmers cannot afford purchase of chemical fertilizers. Indeed [3], has estimated that if only legumes grains are harvested and the residues are effectively recycled, net accrual from the incorporation of legumes can be as much as 140kg/N/ha depending on the legume. The objective of the research was therefore to determine the effect of cowpea residual N on the growth and grain yield of maize. 2. MATERIALS AND METHODS The research work was carried out at the Crops Research Institute (CRI) at Fumesua-Kumasi from September 2014 to December 2014. Fumesua is located within latitude 6 0, 41 North and longitude 1 o , 28 West. The area has bimodal rainfall pattern with the major season rains around April to June and minor season rains from August to November with annual rainfall of 1,345mm per annum. The temperature is usually high throughout the year with annual mean temperature between 22 o C - 31 o C. The vegetation is that of humid forest type. The soil type is Ferric Acrisol Asuansi Series [1]. During the major season, 10 improved cowpea varieties were evaluated for their N fixation potentials. Following harvest of the grains, all haulms were carefully deposited back on their respective plots. To avoid contamination, weeds on the plots were sprayed with glyphosate on 12th September 2014 and seeds of the maize variety Abotem were sown on 15th September at a Spacing of 75cm x40cm. Abotem is an extra early maize (80-85 days) recently released by the CRI. No fertilizer was applied unto the plots except the extra plot added to each replication where no cowpea was planted and thus no residues were incorporated. These plots received the recommended rate of 2 bags of NPK 15-