ANS:B - Ammonium sulphate

The most suitable fertilizer for paddy (rice) cultivation is Ammonium sulphate. Paddy requires a fertilizer with a high nitrogen content, as nitrogen is crucial for the growth and development of the plant, particularly during the vegetative stage. Ammonium sulfate is an excellent nitrogen fertilizer for paddy cultivation for several reasons:

1. High Nitrogen Content: Ammonium sulfate typically contains around 21% nitrogen, making it a good source of nitrogen for paddy plants.
2. Acidifying Effect: Paddy fields often have alkaline soils, and ammonium sulfate has an acidifying effect when applied, which helps to neutralize alkalinity and create a more suitable pH range for paddy cultivation.
3. Ammonium Form: Ammonium sulfate supplies nitrogen in the ammonium form, which is readily absorbed by paddy plants. Ammonium nitrogen is preferred over nitrate nitrogen in flooded paddy fields because it is less prone to leaching in waterlogged conditions.
4. Sulfur Content: In addition to nitrogen, ammonium sulfate also contains sulfur, which is another essential nutrient for paddy plants. Sulfur deficiency can affect rice yield and quality, so the sulfur content in ammonium sulfate helps to address this requirement.