ANS:B - calcium ammonium nitrate.

Calcium ammonium nitrate (CAN) is a type of nitrogen fertilizer that contains both calcium and ammonium nitrate. It is a widely used fertilizer in agriculture for providing essential nutrients to crops. CAN is typically granular in form and can be applied to soil directly. Here's a breakdown of calcium ammonium nitrate:

1. Composition: CAN consists of calcium nitrate (Ca(NO3)2) and ammonium nitrate (NH4NO3). These compounds provide essential nutrients to plants:
   • Calcium Nitrate: Provides calcium (Ca2+) and nitrate (NO3-) ions. Calcium is essential for cell wall structure, enzyme activation, and overall plant growth. Nitrate serves as a readily available form of nitrogen (N) for plants.
   • Ammonium Nitrate: Provides ammonium (NH4+) and nitrate (NO3-) ions. Ammonium is another form of nitrogen that plants can uptake and utilize.
2. Nutrient Content: CAN typically contains around 25-28% nitrogen by weight. It also provides a source of calcium, which contributes to overall plant health and development.
3. Benefits:
   • Balanced Nutrition: CAN provides both calcium and nitrogen, addressing the nutritional needs of crops for optimal growth and development.
   • Quick Nutrient Availability: Being highly soluble, CAN dissolves rapidly in soil moisture, making essential nutrients available to plants soon after application.
   • Reduced Nitrogen Loss: The combination of ammonium and nitrate nitrogen in CAN helps minimize nitrogen loss through leaching and volatilization, improving nutrient use efficiency and reducing environmental impact.
4. Application: CAN is commonly used as a top-dressing fertilizer for crops during the growing season. It can be broadcast over the soil surface or applied through irrigation systems. CAN is suitable for a wide range of crops and soil types.