The Eleventh Regional Wheat Workshop For Eastern ... - Cimmyt

-AGRONOMIC AND ECONOMIC EVALUATION
OF THE ON-FARM NAND P RESPONSE OF BREAD WHEAT
GROWN ON TWO CONTRASTING SOIL TYPES IN CENTRAL ETHIOPIA
Amsal Tarekegne 1 , D.G. Tanner2; Taye Tessema 3 and Chanyallew Mandefro 1
1Holetta Research Center (EARO), P.O. Box 2003, Addis Ababa, Ethiopia
2CIMMYT/CIDA Eastern Africa Cereals Program, P.O. Box 5689, Addis Ababa, Ethiopia
3Ambo Research Center (EARO), P.O. Box 2003, Addis Ababa, Ethiopia
ABSTRACT
Nutrient deficiency is one of the major constraints to wheat (Triticum spp.)
production in Ethiopia. A multi-location on-farm Nand P fertilizer trial was
conducted during the 1995 and 1996 cropping seasons in a poorly drained
Vertisol zone, using an improved drainage technique, and in a highlyweathered
reddish-brown Nitisol zone in the central highland of Ethiopia. The
objectives were to determine yield and yield component response of a
recently-released, high-yielding bread wheat (T aestivum) cultivar to applied
nitrogen (N) and phosphorus (P) rates, and to generate zone-specific,
economically-optimal Nand P recommendations for wheat production in
central Ethiopia. The results from the combined analyses for each zone
indicated a highly significant yield response to fertilizer application. Wheat
grain yield responded significantly to both Nand P in each soil zone, although
the response to N was more pronounced. N by P interaction was nonsignificant
for virtually all crop parameters studied in both zones. Optimum N
and P20S nutrient rates were established for each zone using discrete and
continuous economic analyses under three cost/price scenarios. Optimum
nutrient rates were presented in a user-friendly tabular format for ease of
interpretation by extension staff and policy-makers. Such a tabular format
provides a dynamic template for extension staff to' use when determining rates
of Nand P20S to recommend, facilitates interpolation of cost/price levels, and
can provide insights for policy-makers when estimating the potential impact of
policy interventions affecting grain and nutrient price levels.
INTRODUCTION
Wheat is a principal traditional cereal crop in the highlands of Ethiopia and is produced
exclusively under rainfed conditions at altitudes ranging from 1500 to 3000 m a.s.l. (Hailu,
1991). The central highland of Ethiopia is historically an important wheat-growing region. In
this region, wheat ranks second in total area coverage, production and market demand after
tef (Eragrostis te!) (CSA, 1997a), and is produced across a range of soil conditions,
particularly on well-drained highly-weathered reddish-brown soils (Nitisols) and poorlydrained
heavy dark clay soils (Vertisols) (Asnakew et al., 1991; Hailu, 1991). Of the total
current wheat production in the country, 33% comes from the central highland region (CSA,
1997a).
239