ABSTRACT
Nutrient mining due to sub-optimal fertilizer use on one hand and unbalanced fertilizer use on the other have favored the emergence of multi-nutrient deficiency in Ethiopian soils. Therefore, the study was conducted on twenty-six farmers' fields in Dugda District of East Shewa Zone of Oromia, during the main cropping seasons of 2018-2020. These studies were conducted to determine the economically optimum rate of nitrogen fertilizer in the first year Phosphorus critical (Pc) and phosphorus requirement factor (Pf) in the second year respectively. The treatments consisted of factorial combinations of three levels of TSP (0, 100, and 200) kg ha-1 with six levels of nitrogen (0, 23, 46, 69 92, and 115) kg ha-1 that gave a total of eighteen treatments. However, in the second two consecutive years, the experiment was conducted to determine phosphorus critical (Pc) and phosphorus requirement factor (Pf), and the treatments consisted of six levels of phosphorus (0, 10, 20, 30, 40, and 50) kg ha-1 combined with a single level of nitrogen (69 kg ha-1) that gave a total of seven treatments. The experiments were laid out in randomized complete block design (RCBD) with two replications and the gross plot size was 4 m x 5 m (20 m2) were used to determine optimum nitrogen in the first year and 4m x 5m (20 m2) and phosphorus critical (Pc) and also harvested from 4m2 plot areas. The analysis of variance indicated that Plant height, spike length, number of seeds per spike, biomass yield, and grain yield were highly significantly (p <0.01) influenced by the main effect of nitrogen fertilizer rates. However except for the number of seed per spike, TSP fertilizer significantly (p<0.05) affect plant height and the number of seed per spike as well as highly significantly (p <0.01) biomass and grain yield of bread wheat. The highest (68.76 cm) plant height, the highest (41.02) seed per spike, the highest (8867 kg ha-1) biomass, and the highest (3293 kg ha-1) grain yield were recorded by 200

ABSTRACT
Soil salinity problem is predominantly severe in developing countries, particularly in arid and semiarid regions, resulting in short-term damage to people's livelihoods and long-term repercussions on the country's food security. It is also a major challenge in Ethiopia and west Hararghe in particular where small-scale irrigated agriculture is practiced. Against this backdrop, this study was conducted to assess irrigation water quality in dry season wheat production in Dhungeta, Hule Mandhera, and Kinteri irrigation sites in west Hararghe Zone, Ethiopia. Based on an in-situ field survey, 9 composite irrigation water samples were collected by mixing several sub-samples. The mean water pH at Dhungeta (7.00), Hule Mandhera (7.94), and Kinteri (7.45) fields were grouped in the normal range for irrigation water. The salinity hazard of irrigation water at Dhungeta was medium (0.67 dSm-1), Hule Mandhera high (1.03 dSm-1) and Kinteri (0.99 dSm-1). The total mean of dissolved salt showed water has no restriction for use at Kinteri (153.6 mg L-1) and Dhungeta (426.67 mg L-1) while slight to moderate restriction of water for use was recorded at Hule Mandhera (708.27 mg L-1). The sodicity (alkalinity) hazard class of irrigation water was S1 (low sodium hazard). The mean of residual sodium carbonate was a marginal hazard at Hule Mandhera and safe at Dhungeta and Kinteri. Based on the permeability index, magnesium hazard water was found to be suitable for irrigation. Kelley’s index, Percentage sodium (Na+ %), and potential salinity specified that Hule Mandhera water is unsuitable whereas Dhungeta and Kinteri water were suitable for irrigation. Irrigation water is grouped as a low restriction (70-85) based on the irrigation water quality index. Generally, there is a prospect to decide that the irrigation water quality of the study sites is suitable for wheat production.

ABSTRACT
Participatory on-farm pre-extension demonstrations of soil test crop responses fertilizer recommendations were carried out for bread wheat production in the Sinana District. The study aimed to evaluate and demonstrate soil test crop responses fertilizer recommendations for bread wheat production and to enhance farmers' understanding and capabilities. The experiment was conducted across seven farmers' fields, with each field allocated 0.25 hectares per treatment. The treatments applied were based on specific recommendations using optimum nitrogen (46 kgha-1), phosphors requirement factor (Pf) (5.24), phosphorus critical level (Pc) (22 ppm) using bread wheat Galan verity 150 kgha-1 as test crop. During the experimental conducted in the Sinana District, two Farmer Research Groups (FRGs) having a total of 15 members were established. The results indicated that the highest grain yield of 60.325 kgha-1 was achieved with soil test-based fertilizer recommendations, while the lowest yield of 44.25 kgha-1 was obtained using traditional farmer practices. Soil test-based fertilizer recommendations significantly enhanced grain yield compared to traditional farmer practices, highlighting the effectiveness of targeted fertilizer application in optimizing crop production. Furthermore, the partial budget analysis demonstrated that soil test-based fertilizer recommendations yielded a net profit of 310,563.66 birr, with a remarkable marginal rate of return of 1190.83%. In contrast, the blanket recommendations used in traditional farmer practices were less profitable. Therefore, the dissemination of soil test-based fertilizer recommendations should be prioritized in the Sinana District and similar soil type and agroecology through scaling up and large-scale production is recommended.