Agronomic and economic evaluation of the N and P response of bread wheat grown in the moist and humid midhighland vertisols areas of Arsi zone, Ethiopia

Abstract

Field experiment was conducted in 2012 and 2013 in three districts of Arsi zone, Oromia region, Ethiopia to evaluate the response of bread wheat cultivar "Damphe" under highland vertisols to treatments consisting of 20 factorial combinations of five N rates from urea and four P205 rates from triple super phosphate (TSP). The treatments were laid out in RCBD, replicated three times. All data were subjected to analysis of variance using SAS 9.0 Statistical Analysis Software. Treatment effects on the average grain yield (AGY) and average biological yield (ABY) were very highly significant. Number of spikes m-2, number of seeds/spike, and plant height were also significantly or very significantly affected. The main effects of fertilizer N on AGY, ABY, protein and wet gluten contents, and zeleny values of grains were also very highly significant. Leaf absorption of N increased with increased rates up to 92 kg/ha N. The N recovery efficiency (NRE) at 46 and 92 kg N/ha was 20.9% and 29.4% and the agronomic efficiency (AE) was 10.8 and 13.3 kg grain/ kg N applied, respectively. Above the 92 kg/ha N the increase in both NRE and AE declined or fell reaching 31.4 % and 12.6 kg grains/ kg N. Based on farmers capacity to invest and their inherent tendency to gradually adopt higher rates, a base recommendation of 92-46 (N-P 2 O 5 ) kg/ha, which is equivalent to 160 kg/ha Urea + 100 kg/ha DAP is given. This rate was the treatment with highest marginal rate of return (MRR). Additional recommendation consisting of 138-69, and 115-46 (N-P 2 O 5 ) kg/ha, equivalent to 240 kg/ha Urea + 150 kg/ha DAP and 210 kg/ha Urea + 100 kg/ha DAP is given, based on agronomic data, economic analysis, complexity in management history of different farms, and environmental considerations.

Wheat yield gaps across smallholder farming systems in Ethiopia

“…0.27% with 1% increase in N applied (Table 3). Earlier studies also identified N fertilisation as a key determinant of wheat yields in Ethiopia (Habte et al 2014;Tanner et al 1993) but further research should investigate whether increasing N rates is economically viable for smallholders (cf. van Dijk et al 2017).…”

“…Previous research concluded wheat yield gaps in West Arsi, one of the wheat belts in Ethiopia, can be largely attributed to technology yield gaps (Silva et al 2019a). This means that technologies currently used by farmers do not reach agronomic best practices and that considerably more and better use of inputs is needed if wheat yield gaps are to be narrowed (Habte et al 2014;Tanner et al 1993). Competition for labour during sowing, weeding, and harvesting was also observed in this administrative zone, as labour peaks for other cereal and legume crops overlap with labour peaks for wheat.…”

Impact of silicate fertilizer on soil properties and yield of bread wheat in Nitisols of tropical environment

“…Soil acidity and depletion of essential plant nutrients are among the major abiotic stresses that constrained wheat productivity in Ethiopia in general and in the study area in particular [ [11] , [12] , [13] , [14] , [15] , [16] ]. About 43 % of the cultivable land in Ethiopia is affected by soil acidity [ 12 ], of which about 28 % is categorized under strongly acidic (pH < 5.5) (11).…”