Figures (1)  Tables (4)

    • Figure 1.  Map of the study site.

    • Treatment (P2O5 + K2O)Input costsApplication cost Labor cost (ETB)Total variable cost
      TSPKCl
      0:00.000.000.000.00
      0:1000.001,100.00400.001,500.00
      0:2000.002,200.00400.002,600.00
      0:3000.003,300.00400.003,700.00
      34.5:0422.6250.00200.00622.20
      34.5:100422.6251,100.00400.001,922.60
      34.5:200422.6252,200.00400.003,022.62
      34.5:300422.6253,300.00400.004,122.62
      69:0845.250.00200.001,045.2
      69:100845.251,100.00400.002,345.2
      69:200845.252,200.00400.003,445.2
      69:300845.253,300.00400.004,545.2
      TSP (Triple Super Phosphate), KCl (Potassium Chloride), ETB (Ethiopian Birr).

      Table 1.  Fertilizer input costs, application costs, and total variable costs.

    • Treatment (P2O5 + K2O)AY (t/ha)ADY (t/ha)FP/Q (00 ETB)GFPTVC (ETB/ha)NB (ETB/ha)
      0:021.1919.07550.00104,885.000.00104,885.00
      0:10022.4920.24550.00111,320.001,500.00109,820.00
      0:20024.9622.46550.00123,530.002,600.00120,930.00
      0:30022.0419.84550.00109,120.003,700.00105,420.00
      34.5:020.4718.42550.00101,310.00622.2100,687.40
      34.5:10038.5734.71550.00190,905.001,922.6188,982.40
      34.5:20048.3243.49550.00239,195.003,022.6236,172.40
      34.5:30039.9235.93550.00197,615.004,122.6193,492.40
      69:025.7023.13550.00127,215.001,045.2126,169.8
      69:10033.8930.50550.00167,750.002,345.2165,404.8
      69:20042.3738.13550.00209,715.003,445.2206,269.8
      69:30038.1234.31550.00188,705.004,545.2184,159.8
      All abbreviations are mentioned above (Parameters of Collected Data).

      Table 2.  P and K fertilizers applications on potato production: a net benefit estimate.

    • Treatment
      (P2O5 + K2O)      		TVC (ETB/ha)NB (ETB/ha)B: C ratio
      0:00104,885.00
      34.5:0622.2100,687.40D161.82
      69:01,045.2126,169.8120.71
      0:1001,500.00109,820.00D73.21
      34.5:1001,922.6188,982.4098.29
      69:1002,345.2165,404.8D70.52
      0:2002,600.00120,930.00D45.51
      34.5:2003,022.6236,172.4078.13
      69:2003,445.2206,269.8D59.87
      0:3003,700.00105,420.00D28.49
      34.5:3004,122.6193,492.40D46.93
      69:3004,545.2184,159.8D40.51
      TVC: total variable cost, NB: net benefit, B: C ratio: benefit-cost ratio, D: dominated treatments.

      Table 3.  Dominance analysis of the effect of phosphorus and potassium fertilizer rates on potato tuber yield.

    • TreatmentTVC (ETB/ha)MC (ETB/ha)NB (ETB/ha)MB (ETB/ha)MRR (%)
      0:00104,885
      69:01,045.21,045.20126,169.821,284.82,036.4
      34.5:1001,922.6877.40188,982.4062,812.67,178.9
      34.5:2003,022.61,100.00236,172.4047,190.004,290.0
      NB (Net benefit), MB (marginal benefit), and MRR (marginal rate of return), TVC (total variable cost), and MC (marginal cost).

      Table 4.  Different fertilization rates of phosphorus and potassium affect the potato's marginal return rate (MRR).