The Effects of Nitrogen Fertilizer on Chemical Compositions in Corn and Sweet Sorghum

This study was carried out to evaluate the effects of four nitrogen treatments (50, 100, 150 and 200 Kg urea / ha) on biomass, crude protein, soluble carbohydrates and crude fiber contents in three fodders (corn, sweet sorghum and sweet sorghum bagasse) at the filed experimental station. The results showed the effects of nitrogen treatments and fodders on the above measurements were significant. Treatment of 200 kg/ha urea had the highest biomass (64.80 t/ha) and protein content (8%) and it had the lowest soluble carbohydrates (12.80 %) and fiber contents (31.90%). Between fodders, corn had higher biomass and protein content (72.80 t/ha, 7.10 %) than sweet sorghum (66.50 t/ha, 5.90 %), respectively. Also both carbohydrate and fiber contents of sweet sorghum was higher than corn. Sweet sorghum bagasse had lower crude protein and carbohydrates content and higher crude fiber than both corn and sweet sorghum. In fodders as the nitrogen fertilizer increased, crude protein present increased while crude fiber present decreased which could increase palatability and digestibility of the both species. Thus, base on the results, it is suggested to apply 200 kg/ha urea for corn and sweet sorghum. Key word: Sweet sorghum Corn Bagasse Nitrogen fertilizer Carbohydrate Protein Fiber INTRODUCTION differences in climatic, soil and genotypic factors across Sorghum [Sorghum bicolor L. (Moench)] can be nitrogen requirement is dependent on the yield classified as sweet, grain and forage types [1]. It is well expectation in a given environment as determined by adapted to sub-tropical and temperate regions of the climate, management and cultivar. Depending on soil world and it is water efficient [2]. Sweet sorghum has nitrogen fertility, farmers apply anywhere between 45 and many good characteristics such as a drought resistance 224 kg Nha in sorghum production [13]. Although [3], water-lodging tolerance, salinity resistance [4, 5] and adequate supply of nitrogen to crops is fundamental to with a high yield of biomass etc [6]. It is often grown in optimize crop yields, mismanagement of nitrogen, areas of low fertility and unpredictable rainfall [7]. Sweet such as excessive nitrogen application, can result in sorghum usually is planted for sugar [8] and ethanol contamination of groundwater [17]. Mengel and Kirkby production [9, 10]. It is a C4 crop with a high biomass [18] mentioned that corn and sorghum yield would have yield and good nitrogen used efficiency [11]. Nitrogen is dropped by 41% and 19%, respectively, without nitrogen essential for plants growth [12] and it is still one of major fertilizer application. Application of nitrogen fertilizer factors limiting crop yield [13]. To achieve economically increase sweet sorghum stem yield [19] and corn fodder viable returns, efficient use of available resources, like [20]. Mahmud et al. [21] reported that application of nitrogen, is necessary to maximize yields in all seasons. nitrogen increased crude protein, fodder and dry matter There is a need to use the minimum amount of nitrogen yield in forage sorghum. They also mentioned that plant required for the maximum growth rate at any time during nutrition may not only affect the forage production but the growing season [14]. The nitrogen requirement for also improve the quality of forage from view point of its crop production has traditionally been determined from protein contents. Also, Mullins et al. [22] reported that, field experimentation involving different rates of nitrogen fertilizer increased forge protein content in corn. application of nitrogen fertilizer [15]. Variable responses Where nitrogen levels are limiting, photosynthesis is to the application of nitrogen fertilizer have been not fully used in the synthesis of organic nitrogen observed in maize and in sorghum [16] owing to compounds and sugars are accumulated [23]. Fiber seasons and locations [15]. Who also mentioned that