Fertilizer nitrogen recovery efficiency in the sub-humid highlands of Central Kenya

• Main Authors: Kihanda, F.M, Wood, M, O'Neill, M.K, Palmer, A.F.E
• Format: Conference Proceeding
• Language: English
• Published: Mexico, DF (Mexico) CIMMYT 1997
• Subjects: ABONOS NITROGENADOS; CONTENIDO DE NITROGENO; ENGRAIS AZOTE; FERTILIDAD DEL SUELO; FERTILITE DU SOL; HIGHLANDS; KENIA; KENYA; NITROGEN CONTENT; NITROGEN FERTILIZERS; PLANT PRODUCTION; PRODUCCION VEGETAL; PRODUCTION VEGETALE; REGION D'ALTITUDE; SOIL FERTILITY; SOIL TYPES; TENEUR EN AZOTE; TIPOS DE SUELOS; TYPE DE SOL; ZEA MAYS; ZONA DE MONTANA
• ISBN: 9789686923933; 9686923934

Nitrogen is one of the major soil nutrients limiting maize production in the sub-humid highlands of Central Kenya. Afield experiment was designed to determine fertilizer N recovery by maize, measured by the 15N isotope technique in two major soil types. Fertilizer N recovery in above-ground parts was low, less than 20 Per cent in both soil types. The presence of farmyard manure tended to increase fertilizer N recovery in the acidic andic humic Nitisol but had no effect on fertilizer N recovery in near neutral humic Nitisol. Less than 3 Per cent of N applied in the first season was recovered in the second season. There is evidence of N leaching to the lower soil horizons. In the first 0.5 m of top-soil, there was approximately 25 kg N ha-1 in the acidic andic Nitisols, while between 0.5 and 2.5 m there was an accumulation of more than 450 kg N ha-1. In view of low N recovery and high N leaching, it is important to design strategies for more efficient N utilization by maize and recycling of the large quantities of N accumulated in lower soil horizons. Leaching of N to lower soil horizons may be a greater problem than anticipated by researchers and farmers, or conversely may constitute a large reserve of N.