Feedlot Waste Compost in a Soil System- Lettuce Cultivation

The soil-crop systems of the peri-urban area allow the recovery of chemical elements from the manure generated in intensive livestock production, reducing the risk of contamination of groundwater. This study evaluated the effect of the application of different doses of feedlot waste compost on the lettuce crop ( Lactuca sativa L.) and on the chemical, physicochemical, and biological properties of the soil. In two consecutive years, greenhouse experiments were carried out applying doses equivalent to 128 and 500 kg ha(-1) of nitrogen, determining fresh weight and apparent efficiency of nitrogen recovery in the crop, and in the soil, nitrate content, organic matter, activity overall biological, electrical conductivity, and pH. The yield of the lettuce crop increased between 29 and 55%, with apparent N recovery efficiencies of less than 5%. In the soil, the effects were mainly manifested in the first centimeters, with increases in the contents of organic matter, global biological activity, and electrical conductivity. On the other hand, there were no significant changes in the pH or nitrate content at depths greater than those reached by the roots of the crop.