Figures (7)  Tables (2)

    • Figure 1. 

      Potato marketable tuber yield and total tuber yield response to nitrogen fertilizer application rate.

    • Figure 2. 

      Soil nitrate-N concentration response to N-rate in different growth stages. (Feb 18, Mar 11, Apr 18, 2022, that were 23, 44, and 82 d after planting).

    • Figure 3. 

      SPAD value response to N-rate in different growth stages (Mar 7, Mar 21, Apr 4, and Apr 18, that were 40, 54, 68, and 82 d after planting).

    • Figure 4. 

      Petiole sap nitrate-N response to N-rate in different growth stages. (Mar 7, Mar 21, Apr 4 that were 40, 54, 68 d after planting).

    • Figure 5. 

      Relation of petiole sap nitrate concentration to SPAD value.

    • Figure 6. 

      Yield responses to SPAD value at different growth stages.

    • Figure 7. 

      Marketable yield response to petiole sap nitrate-N in 2021 and 2022 trials.

    • pHCECPKMgCaMnFe
      5.25.937.537.575.5475.5826

      Table 1. 

      Soil properties of the trial field. All the essential elements (PPM) listed were extracted with Mehlich-III.

    • N rate
      (kg/ha)      		Marketable yield
      (kg/ha)      		Total yield
      (kg/ha)      		Specific gravity
      (g/cm3)      		Tuber hollow heart
      (%)      		Corky ring spot
      (%)      		Internal heat
      (%)      		Brown center
      (%)
      0 14,061 ± 1,363d18,949 ± 1,204d1.08 ± 0.00a2.50 ± 1.64a0.00 ± 0.00a0.00 ± 0.00a3.75 ± 1.83a
      45 16,586 ± 755d22,302 ± 776d1.08 ± 0.00a1.25 ± 1.25a0.00 ± 0.00a0.00 ± 0.00a1.25 ± 1.25ab
      90 25,957 ± 1,684c31,594 ± 1,569bc1.08 ± 0.00a1.25 ± 1.25a0.00 ± 0.00a1.25 ± 1.25a0.00 ± 0.00b
      13526,521 ± 1,404bc31,168 ± 1,769c1.08 ± 0.00a2.50 ± 2.50a0.00 ± 0.00a0.00 ± 0.00a0.00 ± 0.00b
      18029,841 ± 1,471abc35,773 ± 1,499abc1.09 ± 0.00a2.50 ± 1.64a0.00 ± 0.00a1.25 ± 1.25a0.00 ± 0.00b
      22529,956 ± 1,016abc35,951 ± 1,401abc1.09 ± 0.00a0.00 ± 0.00a0.00 ± 0.00a0.00 ± 0.00a0.00 ± 0.00b
      27031,784 ± 919abc36,934 ± 751abc1.08 ± 0.00a5.00 ± 1.89a1.25 ± 1.25a0.00 ± 0.00a0.00 ± 0.00b
      31532,680 ± 2,171ab38,270 ± 2,440ab1.08 ± 0.00a6.25 ± 3.75a0.00 ± 0.00a0.00 ± 0.00a0.00 ± 0.00b
      36034,181 ± 1,209a39,875 ± 1,336a1.08 ± 0.00a3.75 ± 2.63a0.00 ± 0.00a0.00 ± 0.00a0.00 ± 0.00b
      Data (mean ± SE, n = 4) followed with same letter in the same column were not significant different according to Tukey HSD at 0.05 level.

      Table 2. 

      The tuber yield and quality of potato grown under different nitrogen fertilizer rates.