Figures (6)  Tables (7)
    • Figure 1. 

      Design diagram of the greenhouse cucumber plot. The green circles show the cucumber plants; the black circles show the soil sampling sites. The units of numbers in the figure are centimeters (cm).

    • Figure 2. 

      The groundwater level during the experiments of 2018 AW, 2019 SS and 2019 AW.

    • Figure 3. 

      The comparison between simulated and measured values of SWC in the 0–10 cm 10–20 cm and 20–30 cm soil layers. The red lines show the simulating value of the HG model (HG); the blue lines show the simulating values of the original model (O); the green dots show the measured values.

    • Figure 4. 

      The comparison between simulated and measured values of SNC in the 0–10 cm 10–20 cm and 20–30 cm soil layers. The red lines show the simulating value of the HG model (HG); the blue lines show the simulating values of the original model (O); the green dots show the measured values.

    • Figure 5. 

      Comparison between simulated and measured values of plant dry weight of two crops. The dates were collected from (a) 2018 AW, (b) 2019 SS, (c) 2019 AW treatment under N2-N4 treatments. The blue circles indicated the N1 treatments; the blue rhombus indicated the N2 treatments; the red square indicated the N3 treatments; the green triangle indicated the N4 treatments. The black line indicated the linear regression equation. The dotted lines show the 1:1 line.

    • Figure 6. 

      Comparison of simulated and measured values of cucumber yield in four N treatments.

    • DateAmount (mm)Mode
      2018AW2018/09/1241.57Drip
      2018/09/1521.39Drip
      2018/09/2027.68Drip
      2018/10/1034.14Drip
      2018/10/1832.29Drip
      2018/10/2226.60Drip
      2018/10/3035.28Drip
      2018/11/0526.82Drip
      2018/11/1542.70Drip
      2018/11/2229.26Drip
      2019 SS2019/03/2449.24Drip
      2019/03/2723.26Drip
      2019/04/1238.24Drip
      2019/04/2547.35Drip
      2019/05/0544.86Drip
      2019/05/1139.17Drip
      2019/05/1658.62Drip
      2019/05/2160.16Drip
      2019/05/3055.27Drip
      2019/06/0546.52Drip
      2019/06/1141.83Drip
      2019/06/1630.02Drip
      2019 AW2019/08/2737.67Drip
      2019/08/3020.48Drip
      2019/09/0528.25Drip
      2019/09/2433.66Drip
      2019/10/0232.58Drip
      2019/10/0721.97Drip
      2019/10/1732.68Drip
      2019/10/2527.4Drip
      2019/10/3031.16Drip
      2019/11/0430.87Drip

      Table 1. 

      Specific irrigation management used in the experiments.

    • DateN1N2N3N4
      2018 AW (kg hm−2)09/1214.217.519.821.5
      09/157.39.010.211.1
      09/209.411.613.214.3
      10/1028.445.463.281.4
      10/1827.744.662.380.5
      10/229.111.212.713.8
      10/3020.430.440.350.2
      11/0529.346.564.582.8
      11/1531.349.067.385.9
      11/2218.327.837.447.0
      2019 SS (kg hm−2)03/2411.113.916.117.3
      03/275.36.67.68.2
      04/1225.241.760.177.7
      04/2527.244.363.080.9
      05/0510.212.714.615.8
      05/118.911.112.813.8
      05/1629.847.566.784.8
      05/2113.617.019.621.2
      05/3020.831.141.851.6
      06/0510.513.115.216.4
      06/1126.042.761.278.9
      06/1615.123.928.642.7
      2019 AW (kg hm−2)08/2713.315.317.021.3
      08/307.28.39.311.6
      09/059.911.512.815.9
      09/2433.050.269.787.0
      10/0232.649.869.286.3
      10/077.78.99.912.4
      10/1732.749.869.286.4
      10/2520.229.439.649.4
      10/3032.249.268.585.5
      11/0421.530.839.749.5

      Table 2. 

      Applied N fertiliser for greenhouse cucumber in the experiments.

    • Soil layer (cm)Bulk density (g·cm−3)Sand (%)Clay (%)pHFC (cm3·cm−3)θs (cm3·cm−3)
      0−101.351.5034.26.700.300.46
      10−201.409.1644.87.050.270.39
      20−301.4111.0737.47.160.290.36
      FC: Field water holding capacity; θs: Saturated water content.

      Table 3. 

      Soil physical and chemical properties for the soil profile at the experimental site.

    • ParametersDescriptionDefault
      value
      Optimized value
      PNINFCrop specific parameters of critical N1.351.20
      B0curve equation33
      RLUXCoefficient for luxury N consumption1.21.2
      TBBase temperature (°C)712
      DdlagLag period before growth begins (°C days)100100
      KrzVertical root penetration rate (m d–1 °C –1 )0.0010.001
      K_iniCrop coefficient in initial stage0.800.50
      K_midCrop coefficient in middle stage1.100.80
      K_endCrop coefficient in end stage1.101.10
      H_maxMaximum crop height (m)0.22.1
      L_iniLength of the initial growth period (d)2020
      L_devLengthof the development period (d)3030
      L_midLength of the middle period (d)7070
      L_latLength of the late growth period (d)1515
      HIHarvest index0.500.55

      Table 4. 

      Parameters used in the HG EU-Rotate_N model.

    • TreatmentSoil layer (cm)RMSENSEd
      Original modelHG modelOriginal modelHG modelOriginal modelHG model
      N10−100.0460.0430.7080.7450.9380.945
      10−200.0570.042−0.0010.4360.8070.876
      20−300.0620.050−0.0140.3440.8240.853
      N20−100.0420.0370.8050.8470.9540.964
      10−200.0610.042−0.2780.3840.7320.840
      20−300.0600.046−0.0420.3840.8350.866
      N30−100.0450.0380.7540.8310.9420.958
      10−200.0420.036−0.0060.2740.7860.834
      20−300.0460.039−0.0140.2570.8220.854
      N40−100.0420.0340.7860.8590.9520.967
      10−200.0480.039−0.0670.3180.7450.818
      20−300.0430.036−0.0220.2780.8290.860

      Table 5. 

      Model evaluation index of SWC.

    • TreatmentSoil layer (cm)RMSENSEd
      Original modelHG modelOriginal modelHG modelOriginal modelHG model
      N10−1021.09816.5370.6660.7950.9190.956
      10−2030.05928.5520.3690.4310.8590.865
      20−3026.17323.5160.5350.6250.8960.915
      N20−1025.12625.1260.5250.5250.9020.902
      10−2027.56322.5410.2820.5200.8710.902
      20−3022.87219.6070.4860.6230.8860.916
      N30−1027.90327.9030.6310.6310.9140.914
      10−2026.18721.9160.4950.6460.9160.929
      20−3024.77519.5580.5400.7130.8740.924
      N40−1027.87535.3320.7580.6310.9450.905
      10−2024.19824.1980.7050.7050.9380.938
      20−3027.05820.8260.4740.6880.8540.916

      Table 6. 

      Model evaluation index of SNC in greenhouse cucumber.

    • TreatmentRMSENSEd
      2018 AW4.1560.7690.687
      2019 SS2.0940.9670.992
      2019 AW3.2480.7760.957

      Table 7. 

      Model evaluation for the greenhouse cucumber yield.