Introduction
Material and Methods
Location and Soil Properties
Soil characteristic | Value |
---|---|
Sand (%) | 87.5 |
Silt (%) | 8.2 |
Clay (%) | 4.3 |
pH (in water solution) | 8.2 |
Total N mg kg soil−1 | 18.4 |
P2O5 (mg kg−1) | 7.2 |
K2O (mg kg−1) | 28.3 |
CaCO3 (%) | 3.8 |
Organic matter (%) | 0.48 |
Bulk density (g cm−3) | 1.56 |
Field capacity at −0.03 MPa (g g−1 dry weight) | 0.11 |
Wilting point at −1.5 MPa (g g−1 dry weight) | 0.56 |
Experimental Design and Treatments
Total N supply (kg h−1) | Fertigation schedules | N per growth stage (%) | Fertigation frequency (kg N h −1) | |
---|---|---|---|---|
7 days | 14 days | |||
(N1) 240 | Control | a | – | – |
Equal | Frequently | 20.0 | 40.0 | |
Wise | Initial (12.5) | 7.5 | 15.0 | |
Developmental (25) | 15.0 | 30.0 | ||
Mid (50) | 30.0 | 60.0 | ||
Mature (12.5) | 7.5 | 15.0 | ||
(N2) 360 | Control | a | a | – |
Equal | Frequently | 30.0 | 60.0 | |
Wise | Initial (12.5) | 11.5 | 23.0 | |
Developmental (25) | 23.0 | 46.0 | ||
Mid (50) | 46.0 | 92.0 | ||
Mature (12.5) | 11.5 | 23.0 |
Growth Stages and Crop Water Requirement
Measurements of Crop Parameters
Plant and Soil Analysis
Statistical Analysis
Results
Potato Yield and Yield Components
Source | Df | Tuber yield | Total dry biomass | Tuber number | Tuber weight |
---|---|---|---|---|---|
Replication | 2 | NS | NS | NS | NS |
Nitrogem (N) | 1 | * | * | NS | * |
Fertigation (F) | 4 | * | * | * | * |
N × F | 4 | * | * | * | * |
Error | 16 | – | – | – | – |
CV% | – | 2.61 | 2.60 | 5.53 | 4.10 |
Nitrogen | Control | Fertigation schedules | ||||
---|---|---|---|---|---|---|
Equal1W | Equal2W | Wise1W | Wise2W | Mean | ||
Tuber yield (t ha−1) | ||||||
N1 | 23.14i | 27.88g | 25.29h | 32.47e | 30.34f | 27.82B |
N2 | 28.56g | 37.84c | 35.15d | 42.76a | 40.13b | 36.89A |
Mean | 25.85E | 32.86C | 30.22D | 37.62A | 35.23B | – |
Total dry biomass (t ha−1) | ||||||
N1 | 6.85i | 8.25g | 7.49h | 9.61e | 8.98f | 8.24B |
N2 | 8.45g | 11.20c | 10.40d | 12.66a | 11.88b | 10.92A |
Mean | 7.65E | 9.73C | 8.94D | 11.13A | 10.43B | – |
LAI (90 days) | ||||||
N1 | 1.75 | 2.18 | 1.85 | 2.35 | 2.17 | 2.06 |
N2 | 2.13 | 3.24 | 3.19 | 3.72 | 3.39 | 3.13 |
Mean | 1.94 | 2.71 | 2.52 | 3.04 | 2.78 | – |
Tuber number (plant−1) | ||||||
N1 | 7.24a | 7.54a | 7.58a | 7.98a | 7.90a | 7.24A |
N2 | 7.38a | 7.51a | 7.56a | 7.66a | 7.79a | 7.38A |
Mean | 7.31A | 7.52A | 7.57A | 7.82A | 7.84A | – |
Tuper weight (g plant−1) | ||||||
N 1 | 82i | 90g | 86h | 98e | 93f | 90B |
N 2 | 88g | 112c | 108d | 128a | 119b | 111A |
Mean | 85D | 101C | 97C | 113A | 106B | – |
Nitrogen Uptake, Recovery, and NUE
Nitrogen | Control | Fertigation schedules | ||||
---|---|---|---|---|---|---|
Equal1W | Equal2W | Wise1W | Wise2W | Mean | ||
Total N uptake (kg h−1) | ||||||
N1 | 101 | 133 | 114 | 155 | 139 | 128 |
N2 | 143 | 192 | 169 | 222 | 195 | 184 |
Mean | 122 | 162 | 142 | 189 | 167 | – |
N recovery (%) | ||||||
N1 | 42 | 55 | 48 | 65 | 58 | 53 |
N2 | 40 | 53 | 47 | 62 | 54 | 51 |
Mean | 41 | 54 | 47 | 63 | 56 | – |
NUE (kg yield kg−1 N) | ||||||
N1 | 96 | 116 | 105 | 135 | 126 | 116 |
N2 | 79 | 105 | 98 | 119 | 111 | 102 |
Mean | 88 | 111 | 102 | 127 | 119 | – |