A method for engineering a transgenic plant that replicates the nitrogen fixation mechanism of photosynthetic bacteria, such as cyanobacteria, or that of other bacteria, by targeting to or expressing in plant plastids bacterial nif (nitrogen fixation) genes is provided. A method for reducing the overall concentration of nitrogen in soil is provided using a plant that replicates the nitrogen fixation mechanism of photosynthetic bacteria. Progeny of a plant that replicates the nitrogen fixation mechanism of photosynthetic bacteria is also provided.MÉTODO PARA DISMINUIR LA CANTIDAD DE NITRÓGENO EN EL SUELO, BASADO EN EL CULTIVO DE ESPECIES VEGETALES QUE EXPRESAN LOS GENES nifHDK CODIFICANTES PARA UNA NITROGENASA PROCARIÓTICA, Y PRODUCTOS COMERCIALES DERIVADOS DE LAS MISMAS.