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ESTIMATION OF CROP WATER REQUIRMENT OFDIFFERENT CROPS GROWN IN KUMLUR. By, NISHIT AMAN BTE-06-022. GREEN GRAM. Season – Rabi ( Starting Nov) Kharif ( Starting March) Temperature – 30- 35 degree Celsius Soil Type - Loamy soil.
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ESTIMATION OF CROP WATER REQUIRMENT OFDIFFERENT CROPS GROWN IN KUMLUR By, NISHIT AMAN BTE-06-022
GREEN GRAM • Season – Rabi ( Starting Nov) Kharif ( Starting March) • Temperature – 30- 35 degree Celsius • Soil Type - Loamy soil
HOW TO CALCULATE CWR? • Calculate reference Evapotranspiration • Find out crop coefficient of the green gram during different stages of growth. • Multiply both to get actual evapotranspiration.
DATA COLLECTED FOR CALCULATION • Date of sowing – 1st march • Date of harvest – 8th June • Altitude of Kumulur – 78 m • Latitude of Kumulur - 10°8’ • Relative humidity – 80% • Mean Max. temperature during March, April May and June are 32.4°C,36.3°C 38.0°C and37°C • Mean Min. temperature during March, April May and June are 22.4°C, 24.7°C, 26.6°C, and 26.1°C
ESTIMATION OF ET0 • Modified Penman method • Mean max. temperature for four month is 35.57°C. • Mean min. temperature for the four month is 24.95°C. • Mean air temperature will be 30.26 • Mean sunshine Hour (n) 3.43 • Maximum Possible Sunshine hour 12.3 • n/N will be 0.28
Cont.. • Extra-terrestrial radiation(Ra) in mm/day 12.74 (from the table). • Wind speed = 6km/hr or 144km/day
AERODYNAMICS TERM • ea = 42.41 mbr ( From the table) • ed = RH/100 × ea = .0.80 ×42.41 = 33.92mbr • ea – ed = (42.41 - 33.92) mbr = 8.49mbr • f(u) = 0.66 • ( 1- W) = 0.2184 ( from the table)
RADIATION TERM • Rns = Ra× 0.292 = 12.74 ×0.292 = 3.72 • Rnl = f(t) × f(e) × f(n/N) = 16.75 ×0.1 ×0.354 = 0.59 • Rn = Rns – Rnl = 3.72 - 0.59 = 3.13
Cont… • W = 0.781 • ET0 (Unadjusted) = W Rn + (1-W).f(u)(ea - ed ) = (0.781 × 3.13) + 0.2184 ×0.66 ×8.49 = 3.66mm/day • ET0 = c × ET0 = 1.09 × 3.66 = 3.99 mm/day
DETERMINATION OF CROP COFFICIENT • Initial Stage - 20days • Development stage – 30 days • Middle stage – 30 days • Late stage – 20days
Initial Stage • From 1st march to 20 march • Kc = 0.5 • ET0 = 3.99mm/day • ET = Kc ×ET0 = 0.5 × 3.99 = 1.995mm/day = 39.9mm/stage
Development stage • From21st march to 20th April • Kc = 1.05 • ET0 = 3.99mm/day • ET = Kc ×ET0 = 1.05 × 3.99 = 4.1895 mm/day = 125.685 mm/Stage
Middle stage • From20st April to 19th May • Kc = 1.02 • ET0 = 3.99mm/day • ET = Kc ×ET0 = 1.02 × 3.99 = 4.151 mm/day = 124.53 mm/Stage
LATE STAGE • From20st MAY to 10th May • Kc = 0.9 • ET0 = 3.99mm/day • ET = Kc ×ET0 = 0.9 × 3.99 = 3.591 mm/day = 71.82 mm/Stage
Cont… • Total water requirement from day of sowing to day of harvesting will be summation of all. • 39.9mm+125.685 mm +124.53 mm + 71.82 mm = 361.935mm
Result • Total water requirement of the green gram as calculated by Modified penmen method is 361.93mm.