31/01/2024
លំហាត់
រកតម្រូវការទឹកសម្រាប់ដំណាំប៉េងប៉ោះ
តើមាន ETo= (មករាមាន 0.4, គុម្ភៈមាន 5, មិនាមាន 5.8, មេសាមាន 6.3, ឧសភាមាន 6.8, មិថុនាមាន 7.1) និង Kc, initial stage = 0.45
Kc, crop development stage =0.75
Kc, mid season stage = 1.15
Kc, late season stage = 0.8
ចាប់ផ្តើមដាំថ្ងៃទី ១ ខែគុម្ភៈ ឆ្នាំ២០២៤ ដែលមានអាយុកាលដាំ 150 ថ្ងៃ។
ដំណោះស្រាយ
Planting date 1 Feb
Initial stage, 35 days 1 Feb-5 Mar
Crop development stage, 40 days 6 Mar-15 Apr
Mid season stage, 50 days 16 Apr-5 Jun
Late season stage, 25 days 6 Jun-30 Jun
Last day of the harvest 30 Jun
រក Kc
February: Kc Feb = 0.45
March: 5 days: Kc = 0.45
25 days: Kc = 0.75
NOTE: The Kc values are rounded to the nearest 0.05 or 0.00.
Thus Kc, March = 0.70
April: 15 days: Kc = 0.75
15 days: Kc = 1.15
Thus Kc, April =0.95
May: Kc, May = 1.15
June: 5 days: Kc = 1.15
: 25 days: Kc = 0.80
Thus Kc, June =0.85
ET crop = ETo × Kc (mm/day)
February: ET crop = 5.0 × 0.45 = 2.3 mm/day
March: ET crop = 5.8 × 0.70 = 4.1 mm/day
April: ET crop = 6.3 × 0.95 = 6.0 mm/day
May: ET crop = 6.8 × 1.15 = 7.8 mm/day
June: ET crop = 7.1 × 0.85 = 6.0 mm/day
រកតម្រូវការទឺកប្រចាំខែ
February ET crop = 30 × 2.3 = 69 mm/month
March ET crop = 30 × 4.1 = 123 mm/month
April ET crop = 30 × 6.0 = 180 mm/month
May ET crop = 30 × 7.8 = 234 mm/month
June ET crop = 30 × 6.0 = 180 mm/month
ប្រភពៈ
3.1 INFLUENCE OF CLIMATE ON CROP WATER NEEDS (ETo) 3.2 INFLUENCE OF CROP TYPE ON CROP WATER NEEDS (Kc) 3.3 CALCULATION OF THE CROP WATER NEED
