Nitrogeno : Fuentes quimicas y biologicas en la fertilizacion del frijol

A report is presented on N fertilization and fixation in bean crops. The selection of N sources, the time of application and the amount applied guarantees a higher utilization of N by the plant. When the total amount of N required is applied prior to planting, the plant only uses 26 percent of the fertilizer supplied. Nodulation and N-fixation are affected by the supply of an appropriate rhizobium, its specificity with the host, soil pH and temp., nutritional factors, the use of toxic products, cultural factors and the existence of Rhizobium in the soil. Graphics are presented on the levels of N-fixation. (CIAT)