Q1: Fertiliser value of a nitrogeneous fertiliser is expressed in terms of its __________ content.

ANS:A - N₂

N2 refers to nitrogen gas, which is a diatomic molecule composed of two nitrogen atoms bonded together. In the context of fertilizers, N2 specifically refers to the nitrogen component present in the form of gas. Nitrogen is an essential nutrient for plant growth and development, playing a critical role in various biological processes such as photosynthesis, protein synthesis, and chlorophyll production. However, nitrogen gas (N2) itself is inert and cannot be directly utilized by most plants. Instead, plants rely on nitrogen in the form of compounds such as ammonia (NH3), nitrate (NO3-), and urea (CO(NH2)2). In agricultural practices, nitrogen fertilizers are commonly used to provide plants with an accessible source of nitrogen. These fertilizers contain nitrogen in various forms, such as ammonium nitrate, urea, ammonium sulfate, and others. When applied to the soil, these nitrogen-containing fertilizers undergo processes such as mineralization, nitrification, and ammonification, which convert the nitrogen into forms that plants can uptake and utilize for growth. Therefore, while N2 is abundant in the atmosphere, it must be converted into more accessible forms of nitrogen to be beneficial as a fertilizer for plants.