Land application is where farmers apply biosolids to their land. Biosolids are organic materials resulting from the treatment of domestic sewage in a wastewater treatment facility; they do not come from septic tanks, industrial or food processing facilities, or animals.. Biosolids can provide the soil with important macronutrients such as nitrogen, phosphorus, and potassium (N, P, K) like those found in conventional fertilizers. Micronutrients such as zinc, copper, and molybdenum can also be found in biosolids. 

Using recommendations from soil tests, farmers apply nitrogen found in biosolids at a rate needed by the crops they will be planting. Soils low in organic matter can also benefit from the carbon content received by biosolids land application. Furthermore, there is an economic benefit in using biosolids over commercial fertilizer, as biosolids are often supplied at no cost to the farmer.