Verification of Soil Test Based Phosphorous Calibration Study for Bread Wheat (Triticum Aestivum L.) Production in Horo District, Oromia Regional State, Ethiopia

Abstract

On-farm verification trial of soil test based crop response phosphorous calibration study for bread wheat production was conducted in 2019/20 main cropping season in the Horo District of the Horo Guduru Wollega Zone. The trial was initiated to verify phosphorus critical level and requirement factor for bread wheat production in Horo District. The treatments were the control (without phosphorus fertilizer), farmers practice (blanket recommendation) and soil test based recommended phosphorus fertilizer rate (RR). The trial was conducted on six farmers' field across the district. Plot size was 10m * 10m. Soil data before planting and yield data were collected throughout the trial. Soil reaction pH (H 2 O) of all the sites ranged from 4.73 to 5.42 and available P ranges from 1.4 to 12.6ppm. Soil acidity of the experimental sites were amended with lime. Bread wheat grain and biomass yield (kg/ha) were high and significantly (p< 0.01) affected by different fertilizer rates used as treatments. The highest grain yield (2875 kg/ha) was resulted with soil test based phosphorus fertilizer rate recommendation. Economically optimum N (46 kg/ha), critical level phosphorus (10 ppm) and phosphorus requirement factor (11.03 kg/ha) for bread wheat production in the district were gained and recommended during the calibration study. It was significantly higher than the grain yield gained from the farmers' practice (2119.4 kg/ha) and control/without phosphorus fertilizer (1647.2 kg/ha). Similarly, soil test based phosphorus fertilizer rate recommendation was economically optimum and feasible for bread wheat production in the district.

Pre-extension Demonstration of Soil Test Based NPS Fertilizer Recommendation under Lime Application for Bread Wheat (Triticum aestivum) in Horo Distric at Horo Guduru Wollega Zone, Oromia Region, Ethiopia

“…This could occur as a result of long-term inorganic fertilizer application and persistent cultivation, which are caused by the low pH of the soil in the study area. This result agreed with the finding of Temesgen and Chalchisa [8]. The most extreme and least values of available P were 8.53 and 2.7 ppm, respectively (Table 1).…”

“…Application of Phosphorus in kg/ha = (P critical -P initial)*P requirement factor. Financially ideal N (46 kg/ha), critical level phosphorus (10 ppm) and phosphorus requirement factor (11.03 kg/ha) for bread wheat production within the district were picked up and recommended during the calibration study phosphorous as stated by Temesgen and Chalchisa [8]…”