Certified Crop Advisor Practice Exam 2025 – Complete Study Resource

Irrigation water is typically not a good source of nitrogen because its primary function is to provide moisture for crops rather than nutrients. While some irrigation water may inadvertently contain small amounts of nitrogen due to runoff or certain types of water sources, it is not a reliable or significant source compared to other options listed.

Livestock manure, composted plant material, and ammonium nitrate are all recognized for their nitrogen content. Livestock manure contains not only nitrogen but also other essential nutrients, making it a beneficial addition to soil. Composted plant material may be rich in nitrogen, depending on the types of materials composted and the process used. Ammonium nitrate is a concentrated source of nitrogen frequently used in fertilizers, making it a key source for promoting crop growth. Given this understanding, irrigation water stands out as the least effective option for nitrogen supply.