TY  - PRO
AU  - Kihanda,F.M.
AU  - Edmeades,G.O.|Banziger,M.|Mickelson,H.R.|Peña-Valdivia,C.B.
AU  - O'Neill,M.K.
AU  - Palmer,A.F.E.
AU  - Wood,M.
ED  - Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Mexico DF (Mexico)
TI  - Fertilizer nitrogen recovery efficiency in the sub-humid highlands of Central Kenya
SN  - 968-6923-93-4
U1  - 633.153 
PY  - 1997///
CY  - Mexico, DF (Mexico)
PB  - CIMMYT
KW  - Highlands
KW  - Kenya
KW  - Nitrogen content
KW  - Plant production
KW  - Soil types
KW  - Zea mays
KW  - AGROVOC
KW  - Soil fertility
KW  - Nitrogen fertilizers
KW  - CIMMYT
N2  - 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% 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% 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
ER  -