Abstract:
Soil acidity is one of the soil chemical degradation problems affecting soil productivity in
the Ethiopian highlands. So, amendment of these soils is of paramount importance to
enhance their productivity. This study was conducted during the 2017 cropping season to
determine the effects of lime and phosphorus levels on selected soil properties and bread
wheat yield on acidic soils of Pawe Agricultural Research Center Banja sub-station in Awi
Zone of Amhara National Regional State. The experiment was laid out in randomized
complete block design with three replications. Four levels of lime (0, 3, 4.5 and 6 t ha-1)
and four levels of phosphorus (0, 10, 20, and 30 kg ha-1) were combined in a complete
factorial arrangement. Lime requirement of the soil was calculated based on its
exchangeable acidity. Soil samples were analyzed for Texture, BD, pH, total N, available
P, OC, CEC, exchangeable Al and acidity, exchangeable base (Ca, Mg, K and Na). The
grain and straw samples were also analyzed for concentration phosphorus. Wheat grain
yield, thousand seed weight, biomass yield, number of tillers, plant height, spike length and
number of seeds per plant were collected at recommended time. Then data were managed
properly using the Excel computer software and subjected to the analysis of variance using
the SAS software. Results of soil analysis after one month of liming showed that lime
application significantly (p<0.05) increased soil pH (4.8 to 5.35), available P (12.15 to
15.42), CEC (33.71 to 35.28) and markedly reduced exchangeable acidity (3.08 to 0.44)
and exchangeable Aluminum (2.62 to 0.27). A soil analysis results after harvesting of the
crop indicated that, soil pH values (4.8 to 5.43) were sharply increased by increasing lime
application rates whereas exchangeable acidity(3.59 to 0.40) and exchangeable Al3+ (2.95
to 0.27) highly decreased as the level of applied lime rates increased. However, mean of
plant height, number of tillers per plant, spikes length, numbers of seed per plant, biomass
yield and thousand seeds weight were progressively increased with incremental levels of
lime application. Grain yield recorded from the application of 4.5 and 6 t ha-1 lime
resulted in 84.7 and 96.6 % increment to the control and 11.7 and 18.9% increment to the
3t ha-1 lime. The main effect of P rate had significant (p<0.05) increase on plant height,
biomass yield and thousand seeds weight and grain yield. Additions of 30 kg P ha-1 have
also increased grain yield by about 12.9 % as compared to control (without P additions).
Grain and straw P uptake was increased due to application of lime and P rates which were
mainly associated with increased wheat yields. Moreover, the results showed significant
improvement of wheat yield, plant P uptake and soil chemical properties (soil pH,
available P, CEC and exchangeable acidity and Al3+) due to the main effects of lime and
phosphorus. The optimum economic return (44,703.93ETB ha-1) was recorded from the
combination of 4.5 t ha-1 lime and 30 kg ha-1 P.