Pak. J. Bot., 42(5): 3633-3638, 2010. EFFECT OF INTEGRATED USE OF NITROGEN ON YIELD AND N UPTAKE OF MAIZE CROP AZAM SHAH 1 , MOHAMMAD SHAFI* 2 , JEHAN BAKHT 3 , WISAL MOHAMMAD 1 , MAHMOOD SHAH 1 , M.T. JAN 2 , M. J. KHAN 4 , ZAHIR SHAH 4 AND RAZIUDDIN 5 1 Nuclear Institute for Food and Agriculture Peshawar, Pakistan 2 Department of Agronomy, 3 Institute of Biotechnology and Genetic Engineering, 4 Department of Soil and Environmental Sciences, 5 Department of Plant Breeding & Genetics, KPK Agricultural University Peshawar, Pakistan *Corresponding author E-mail: mshafi.aup@gmail.com Abstract The present field studies investigated the effect of the integrated use of mineral N and organic N sources (Farm yard manure, Poultry manure and Filter cake) on maize crop. Field experiment was carried out on silty clay loam soil at NIFA Tarnab Peshawar Pakistan during 2005-06. There were 17 treatments with four replications using maize variety Azam as a test material in RCB design. Statistical analysis of the data revealed that integrated application of organic N sources (farmyard manure, poultry manure, filter cake) and mineral N source (urea) resulted an upward trend in the yield of maize crop. Maximum biomass, (9554 kgha -1 ) and stover yield (8136 kgha -1 ) of maize were obtained from those treatments where 100% (FYM) was used. Maximum grain yield (1838 kgha -1 ) was recorded from treatment where 25% farmyard manure (FYM) and 75% mineral nitrogen source (urea) were used. Agronomic efficiency and nitrogen use efficiency was also found higher in the treatments where 25% N from farmyard manure (FYM) and 75% N from mineral N source (urea) was applied. It was concluded that combination of 75% mineral N source and 25% organic N sources (urea) are the best combination for sustainable yield. Introduction Among plant nutrients, nitrogen is considered a major element required for high yield of wheat and maize (Ahmad, 2000). Cultivation decreases topsoil contents of organic carbon, total nitrogen and phosphorus in semiarid regions of the world. (Buschiazzo et al., 2000). The farmers are applying chemical fertilizer to overcome the problem of nutrient deficiency and to increase crop yield. However, the chemical fertilizers are expensive and farmers cannot use fertilizers in balanced proportion which have resulted in lower production than the potential demonstrated yield and thus low fertilizer use efficiency (Ahmad, 2000). Under such condition integrated use of mineral and organic N sources can play an important role to sustain soil fertility and crop productivity (Lampe, 2000; Shahban, 2006; Busra et al., 2005; Channabasanagowda et al., 2008). In Pakistan farm yard manure is the most important organic manure. It is estimated that about 1.5 million tones of nutrients are available from farmyard manure (Bari, 2003). The latest estimates showed a population of about 290 million of poultry birds. The droppings of poultry birds are rich in nutrients and if poultry birds droppings are properly collected can contribute about 101 thousand tones of nitrogen, 58 thousand tones of P 2 0 5 , and 26 thousand tones of K 2 0 (Bari, 2003). Pakistan sugar industry is producing about 1.2 million tones of filter cake every year and its solid precipitates collected in vacuum and press filters after carbonation and clarification processes (Nadia & Khwaja, 2006). It has