1.1 Introduction
Nitrogen is an essential element required for successful plant growth. Although inorganic nitrogen compounds account for less than 5% of the total nitrogen in soil (Brady et al., 2008), they are the main form of the element absorbed by most plants. Inorganic and organic fertilizers are applied to maintain the nutritional condition of different cropping systems. According to Mowbot (2021), fertilizers provide plants with the macronutrients they need that might be in short supply in soil. Organic and inorganic fertilizers deliver these nutrients in different ways. Organic fertilizers are natural, in that the nutrients they possess are strictly comprised of plant- or animal-based materials. Either by products or end products of natural processes, Cow manure, decaying leaves, and food compost are all forms of organic fertilizer (Mowbot, 2021).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Limitation of the study and Definition of terms.
1.2 Background of Study
Over the years, researchers discovered that Nitrogen (N) occupies a conspicuous place in plant metabolism system. All vital processes in plants are associated with protein, of which nitrogen is an essential constituent. Consequently to get more crop production, nitrogen application is indispensable and unavoidable. Nitrogen plays a key role in agriculture by increasing of crop yield (Massignam et al., 2009).
Since the previous fifty years, the yield of various crops increased globally due to maximum use of N along with good management practices (Smil, 2001). All plants including cereals; oilseeds, fiber, and sugar producing and horticultural require a balanced amount of nitrogen for vigorous growth and developmental process. Judicious use of N ensures greatest harvest with better quality. Nitrogen is showing a fundamental role in enhancing the productivity of four major crops of Pakistan like, wheat, rice, sugarcane and cotton.
Proper rate of N is essential for improvement of horticultural crops. In this sector, the major crops are citrus, mango, onion and potato in the country. However, vegetables including chilies, tomato, turnip, okra, carrot, cauliflower, peas, tinda gourd, garlic, radish, cucumber etc are also cultivated at a wider range. From the floricultural point of view, the flowers like, marigold, calendula officinale, bougainvillea and rose are important crops. Nitrogen takes good place for enhancement of yield and quality of mango fruit. Application of N fertilizer to mango tree markedly increased the number of fruit tree-1, pulp content as well as fruit quality (Satapathy et al., 2002). The increased fruit yield due to frequent fertilizer application (Sharma et al., 2000). Where as in the citrus, the recommended rate of N for younger plants are commonly depends upon leaf N analysis or N removal in harvested fruit.
Organic fertilizers release nutrients as they break down, improving the soil and its ability to hold water and nutrients. Given time, they make your soil and plants healthier and hardier. Organic fertilizers carry little risk of a toxic overdose of chemicals, but they require a breakdown of microorganisms to release nutrients, limiting their seasonal effectiveness and potentially increasing the amount of time they take to feed your plants (Mowbot, 2021).
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Effects of Nitrogen Fertilizer on Plant Growth.
1.3 Statement of Problems
Investigation revealed that Nitrogen is not an element which is useful for a specific crop or providing limited results for a particular crop. It is great food for every living plant. Nitrogen requirement of horticultural crops is valuable, but its role some time becomes hidden specially in ornamental and large fruit tree crops, mainly due to lack of knowledge and awareness in Nigeria.
A decline in soil fertility leads to a number of consequences. These include a marked decline in crop productivity and food insecurity as the main consequence. The other consequences include less fodder for cattle, less fuel wood for cooking, and less crop residues and cattle manure to recycle nutrients. These effects often increase runoff and erosion losses because there is less plant cover to protect the soil (liu et al., 2018).
1.4 Aim and Objectives of Study
The aim of the study is to identify the Effects of Nitrogen Fertilizer on Plant Growth. In achieving this aim, the following specific objectives were laid out as follows:
- To assess the basic properties of soil and fertilizers in the study area;
- To investigate the effects of Nitrogen fertilizer on soil properties; and
- To identify the effects of nitrogen and nitrate concentrations on plant growth.
1.5 Research Questions
The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:
- What are the basic properties of soil and fertilizers in the study area?
- What are the effects of Nitrogen fertilizer on soil properties?
- What are the effects of nitrogen and nitrate concentrations on plant growth?
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