Biosolids can be used to supply nutrients to crops. The nutrient content and fertilizer replacement value of biosolids and the relationship between biosolids nutrient inputs and crop removal of nutrients are described. Discusses the effects of biosolids processing on nitrogen (N) forms, organic N mineralization rates, and ammonium-N retention and explains how to convert N-availability estimates to application rates. Covers biosolids quality factors (trace element concentrations and pathogen levels), the effects of biosolids applications on soil pH and soil quality, applicable regulations, and questions about biosolids safety and application practices. Includes sources for additional information.