Evapotranspirasi Dan Kebutuhan Air

No UnitBulan

Jan Feb Mar Apr Mei

DATA INPUT

1 Suhu Udara t C 26.720 26.520 27.150 27.750 28.180

2 h % 83.200 84.300 82.100 79.000 76.400

3 μ2 m/dt 0.860 0.990 0.860 0.840 1.000

4 Ql % 47.600 48.600 61.700 68.000 70.600

5 Lintang °LS 7.000 7.000 7.000 7.000 7.000

6 Albedo 0.250 0.250 0.250 0.250 0.250

7 % 40.874 41.660 51.956 56.908 58.952

PERHITUNGAN

8 f(Tai) x 10-2 9.170 9.140 9.210 9.290 9.330

9 ΔL-1 x 102 2.660 2.630 2.710 2.800 2.870

10 PzWa] sa mmHg 26.320 26.300 26.900 27.850 28.490

11 γ + Δ 2.040 2.020 2.070 2.110 2.150

12 = (2) x (10) PzWa mmHg 21.898 22.171 22.085 22.002 21.766

13 f(Tdp) 0.128 0.126 0.127 0.127 0.130

14 (10) - (12) mmHg 4.422 4.129 4.815 5.848 6.724

15 γ x f(μ2) 0.163 0.169 0.163 0.163 0.178

16 = (14) x (15) γ x Eq 0.721 0.698 0.785 0.953 1.197

17 oaHsh x 10-2 9.120 9.160 8.900 8.320 7.640

18 oash x f(r) 0.376 0.379 0.419 0.438 0.446

19 = (17) x (18) 3.426 3.475 3.727 3.644 3.408

20 m = 8 (1-r) 5.422 5.332 4.425 4.003 3.830

21 =1.00-{(20)/10} 0.794 0.797 0.836 0.856 0.866

22 0.107 0.105 0.104 0.098 0.093

23 (19) - (22) 3.319 3.370 3.623 3.546 3.316

24 = (9) x (23) Δ Hshne 8.829 8.863 9.819 9.929 9.516

25 = (16) x (24) γEq x ΔH 6.364 6.184 7.706 9.465 11.388

26 (25 )/ (11) Eto mm/ hari 3.120 3.062 3.723 4.486 5.297

Kelembaban Relatif

Kecepatan Angin

Penyinaran Matahari

m

Transfer ke 12 jam

0,786 Q1+3,46

Tabel Penman 2 dan (1)





PzWa] sa - PzWa


TabelPenman 5 dan (5)

Tabel Penman 6 dan (7) dan (5)

(8) x {1.00 - (7)}

fm = 1 - (m/10)

= (8) x (13) x (21)

27 Jumlah Hari hari 31 28 31 30 31

28 Eto mm/ bln 96.705 85.726 115.411 134.576 164.204

KEBUTUHAN TANAMAN PADI

EVAPOTRANSPIRASI (Eto) 7.845 5.610

Evaporasi (Eo) = 1,1x Eto 8.629 6.171

PERKOLASI (P) 1.000 1.000

Eo+P 9.629 7.171

1.699 3.136

1 0.18 0.306 0.564

2 0.53 0.900 1.662

3 0.55 0.934 1.725

4 0.4 0.680 1.254

5 0.4 0.680 1.254

6 0.4 0.680 1.254

7 0.4 0.680 1.254

8 0.2 0.340 0.627

1 1.2 10.355 7.405

2 1.27 10.959 7.837

3 1.33 11.477 8.207

4 1.3 11.218 8.022

5 1.15 9.924 7.097

6 0 0.000 0.000

PENGOLAHAN TANAH KEBUTUHAN AIR 250 mm selama 30 hari, M = E0+P

15 -0.564

1.8 1.822

15 15.414

15 14.742

1.8 1.769

Evapotranspirasi

Unit OKT NOV

mm/hari

mm/hari

mm/hari

mm/hari

Rh 20% Kering (mm/hr) = R80 basah

FAKTOR HUJAN dengan

2 golongan (FH) tiap 2

mingguan

HUJAN EFEKTIF Re=

HUJAN*FH

KOEFISIEN

TANAMAN PADI

(Kc) (Tabel )

Evapo transpirasi Etc = Eo x Kc

2 Minggu I

Lp (tabel Zylstra IR)

mm/hari

Lp - Re1 mm/hari

(Lp – Re1) x 0.116

lt/dtk

2 Minggu II Lp mm/hari

Lp - Re2 mm/hari

(Lp – Re2)*0.120 lt/dtk

PERTUMBUHAN

Bulan

Jun Jul Agst Sep Okt Nov Des

DATA INPUT

27.680 27.310 27.300 27.690 28.420 28.060 27.140

75.200 71.100 71.500 71.100 74.200 78.100 82.200

1.180 1.090 1.230 1.140 1.110 1.070 0.750

75.200 84.200 85.200 88.100 82.600 65.700 52.500

7.000 7.000 7.000 7.000 7.000 7.000 7.000

0.250 0.250 0.250 0.250 0.250 0.250 0.250

62.567 69.641 70.427 72.707 68.384 55.100 44.725

PERHITUNGAN

9.270 9.240 9.240 9.270 9.370 9.320 9.210

2.790 2.740 2.740 2.790 2.900 2.860 2.710

27.690 27.210 27.210 27.690 29.000 28.320 26.900

2.100 2.080 2.080 2.100 2.180 2.140 2.070

20.823 19.346 19.455 19.688 21.518 22.118 22.112

0.140 0.155 0.154 0.152 0.132 0.126 0.126

6.867 7.864 7.755 8.002 7.482 6.202 4.788

0.187 0.178 0.197 0.187 0.187 0.178 0.161

1.284 1.400 1.528 1.496 1.399 1.104 0.771

7.250 7.370 7.950 8.590 8.990 9.080 9.060

0.462 0.489 0.489 0.501 0.481 0.431 0.392

3.347 3.604 3.888 4.301 4.326 3.909 3.547

3.470 2.805 2.733 2.530 2.962 4.185 5.091

0.875 0.897 0.900 0.909 0.898 0.852 0.811

0.094 0.106 0.113 0.121 0.111 0.107 0.105

3.253 3.498 3.774 4.180 4.215 3.802 3.442

9.077 9.586 10.342 11.662 12.223 10.875 9.327

11.656 13.417 15.799 17.452 17.101 12.005 7.191

5.550 6.451 7.596 8.310 7.845 5.610 3.474

30 31 31 30 31 30 31

166.509 199.969 235.472 249.312 243.186 168.298 107.684

3.474 3.120 3.062 3.723 4.486 5.297 5.550 6.451 7.596 8.310

3.821 3.431 3.368 4.095 4.934 5.827 6.105 7.096 8.355 9.141

1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000

4.821 4.431 4.368 5.095 5.934 6.827 7.105 8.096 9.355 10.141

6.739 5.939 3.701 4.445 4.157 1.756 1.180 0.000 0.359 0.682

1.213 1.069 0.666 0.800 0.748 0.316 0.212 0.000 0.065 0.123

3.572 3.148 1.962 2.356 2.203 0.931 0.625 0.000 0.190 0.361

3.706 3.266 2.036 2.445 2.286 0.966 0.649 0.000 0.197 0.375

2.696 2.376 1.480 1.778 1.663 0.702 0.472 0.000 0.144 0.273

2.696 2.376 1.480 1.778 1.663 0.702 0.472 0.000 0.144 0.273

2.696 2.376 1.480 1.778 1.663 0.702 0.472 0.000 0.144 0.273

2.696 2.376 1.480 1.778 1.663 0.702 0.472 0.000 0.144 0.273

1.348 1.188 0.740 0.889 0.831 0.351 0.236 0.000 0.072 0.136

4.585 4.118 4.041 4.914 5.921 6.992 7.326 8.515 10.027 10.970

4.853 4.358 4.277 5.201 6.267 7.400 7.754 9.011 10.611 11.610

5.082 4.564 4.479 5.447 6.563 7.749 8.120 9.437 11.113 12.158

4.967 4.461 4.378 5.324 6.415 7.575 7.937 9.224 10.862 11.884

4.394 3.946 3.873 4.710 5.675 6.701 7.021 8.160 9.609 10.513

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

PENGOLAHAN TANAH KEBUTUHAN AIR 250 mm selama 30 hari, M = E0+P

16.315 16.789 14.842 17.089 17.395 18.159 17.902 16.765 15.189 14.796

1.958 2.015 1.781 2.051 2.087 2.179 2.148 2.012 1.823 1.775

16.745 17.648 15.806 17.948 17.845 18.159 17.932 16.765 15.189 14.796

15.479 15.118 12.967 15.418 16.52 18.159 17.844 16.765 15.189 14.796

1.858 1.814 1.556 1.85 1.982 2.179 2.141 2.012 1.823 1.775

DES JAN FEB MAR APR MEI JUN JUL AGT SEP

JAN PEB MAR APR MEI JUN JUL

3.148 3.033 3.721 4.486 5.1 5.542 6.451

Eo 3.4628 3.3363 4.0931 4.9346 5.61 6.0962 7.0961

M = Eo + P 4.4628 4.3363 5.0931 5.9346 6.61 7.0962 8.0961

k = MT / S 0.535536 0.520356 0.611172 0.712152 0.7932 0.851544 0.971532

1.7083637 1.6826266 1.8425896 2.0383731 2.2104586 2.3432621 2.6419889

10.762954 10.688675 11.137679 11.649887 12.07074 12.379011 13.026767

Eto (dari Penman)

ek

AGU SEP OKT NOV DES Keterangan

7.596 52.241 49.668 5.603 3.46(mm/hari)

8.3556 8.310 7.845 6.1633 3.806 Eo 1,10 Eto

9.3556 9.3103851 8.8447188 7.1633 4.806 P 1,00 mm/hari

1.122672 1.1172462 1.0613663 0.859596 0.57672 T 30,00 hari

3.0730544 3.0564259 2.8903172 2.3622062 1.7801898 S 250,00 mm

13.868554 13.837845 13.523679 12.421902 10.966039 mm/hari

B U L A N JAN PEB

( A ) ( B )

1 Eto (evapotranspirasi Penman) ( mm / hari ) 3.120 3.062

2 Eo = 1,1 x Eto ( mm / hari ) 3.431 3.368

3 Re terkoreksi ( Ret ) ( mm / hari ) 4.335 2.702

4 1 0.5 EVAPOTRAN- 1.716 1.684

5 Koefisien 2 0.75 SPIRASI 2.574 2.526

6 Tanaman 3 1 TANAMAN 3.431 3.368

7 ( Kc ). 4 1 Etc = 3.431 3.368

8 5 0.82 Eo X Kc 2.814 2.762

9 6 0.45 1.544 1.516

10 PENGOLAHAN TANAH IR 6.026 5.981

11 50 mm IR-Ret A 1.691 3.279

12 SELAMA 15 HARI A x 0.116 B 0.196 0.380

B x 1.25 C 0.245 0.476

C x 1.15 D 0.282 0.547

D x 1.10 E 0.310 0.602

P E R T U M B U H A N

13 KEBUTUHAN AIR A -2.620 -1.018

2 MINGGU KE 1 A x 0.116 B -0.304 -0.118

B x 1.25 C -0.380 -0.148

C x 1.15 D -0.437 -0.170

D x 1.10 E -0.481 -0.187


2 MINGGU KE 2 A x 0.116 B -0.204 -0.020

B x 1.25 C -0.255 -0.026

C x 1.15 D -0.294 -0.029

D x 1.10 E -0.323 -0.032

15 KEBUTUHAN AIR A -0.904 0.666

2 MINGGU KE 3 A x 0.116 B -0.105 0.077

B x 1.25 C -0.131 0.097

C x 1.15 D -0.151 0.111

D x 1.10 E -0.166 0.122


2 MINGGU KE 4 A x 0.116 B -0.105 0.077

B x 1.25 C -0.131 0.097

C x 1.15 D -0.151 0.111

NO

Etc1-Ret

Etc2-Ret

Etc3-Ret

Etc4-Ret

D x 1.10 E -0.166 0.122


2 MINGGU KE 5 A x 0.116 B -0.177 0.007

B x 1.25 C -0.221 0.009

C x 1.15 D -0.254 0.010

D x 1.10 E -0.279 0.011


2 MINGGU KE 6 A x 0.116 B -0.324 -0.138

B x 1.25 C -0.405 -0.172

C x 1.15 D -0.465 -0.198

D x 1.10 E -0.512 -0.218

49.668 5.603 3.46

31 30 31

1539.708 168.09 107.26

mm/hr 1.699 3.136 6.739

52.669 94.08 208.909

0.73 0.73 0.73

38.44837 68.6784 152.50357

1 1 1

50.668 6.603 4.46

1.24027 2.28928 4.91947

1 0.5 24.834 2.8015 1.73

2 0.59 29.30412 3.30577 2.0414

3 0.96 47.68128 5.37888 3.3216

4 1.05 52.1514 5.88315 3.633

5 1.02 50.66136 5.71506 3.5292

6 0.95 3.764 3.594 3.048

Etc5-Ret

Etc6-Ret

Kebutuhan Air Palawija OKT NOV DES

EVAPOTRANSPIRASI (Eto) mm/hari

Jumlah hari hari

Et Crop Bulanan Eto x (30 atau 31) mm/bulan

Hujan 20 % kering R80 basah

Hujan Efektif bulanan. HEB R80 x (30 atau 31) mm/bulan

Faktor Tampungan S (Tabel A2.7)

Hujan Eff. Bulanan Terkoreksi (HEBT) HEB x S

Perkolasi P mm/hari

M = Eo +p Eto + P mm/hari

Re terkoreksi HEB terkoreksi / (30 atau 31) mm/hari

KOEFISIEN TANAMAN Palawija (Kc)

Jagung (Tabel)

Evapotranspirasi : Etc = Eto

Kc

PENGOLAHAN TANAH

3.33 3.33 3.33

2.08973 1.04072 -1.58947

0.24240868 0.12072352 -0.18437852

Kebutuhan Air 50 mm selama 15 hari Lp mm/hari

Lp – Re mm/hari

(Lp - Re) x 0.116 lt/dtk

PERTUMBUHAN

MAR APR MEI JUN JUL AGU SEP OKT

( C ) ( D ) ( E ) ( F ) ( G ) ( H ) ( I ) ( J )

3.723 4.486 5.297 5.550 6.451 7.596 8.310 7.845

4.095 4.934 5.827 6.105 7.096 8.355 9.141 8.629

3.245 3.035 1.282 0.861 -0.025 0.262 0.498 1.240

2.048 2.467 2.913 3.053 3.548 4.178 4.571 4.315

3.071 3.701 4.370 4.579 5.322 6.267 6.856 6.472

4.095 4.934 5.827 6.105 7.096 8.355 9.141 8.629

4.095 4.934 5.827 6.105 7.096 8.355 9.141 8.629

3.358 4.046 4.778 5.006 5.818 6.851 7.496 7.076

1.843 2.221 2.622 2.747 3.193 3.760 4.114 3.883

6.506 7.138 7.838 8.062 8.878 9.957 10.650 10.197

3.261 4.103 6.556 7.200 8.903 9.695 10.152 8.956

0.378 0.476 0.760 0.835 1.033 1.125 1.178 1.039

0.473 0.595 0.951 1.044 1.291 1.406 1.472 1.299

0.544 0.684 1.093 1.201 1.485 1.617 1.693 1.493

0.598 0.753 1.202 1.321 1.633 1.778 1.862 1.643

-1.197 -0.567 1.631 2.191 3.573 3.916 4.073 3.074

-0.139 -0.066 0.189 0.254 0.414 0.454 0.472 0.357

-0.174 -0.082 0.237 0.318 0.518 0.568 0.591 0.446

-0.200 -0.095 0.272 0.365 0.596 0.653 0.679 0.513

-0.220 -0.104 0.299 0.402 0.655 0.718 0.747 0.564

-0.173 0.666 3.088 3.718 5.347 6.005 6.358 5.232

-0.020 0.077 0.358 0.431 0.620 0.697 0.738 0.607

-0.025 0.097 0.448 0.539 0.775 0.871 0.922 0.759

-0.029 0.111 0.515 0.620 0.892 1.001 1.060 0.872

-0.032 0.122 0.566 0.682 0.981 1.101 1.166 0.960

0.850 1.900 4.545 5.244 7.120 8.093 8.644 7.389

0.099 0.220 0.527 0.608 0.826 0.939 1.003 0.857

0.123 0.275 0.659 0.760 1.032 1.174 1.253 1.071

0.142 0.317 0.758 0.874 1.187 1.350 1.441 1.232

0.156 0.348 0.834 0.962 1.306 1.485 1.585 1.355

0.850 1.900 4.545 5.244 7.120 8.093 8.644 7.389

0.099 0.220 0.527 0.608 0.826 0.939 1.003 0.857

0.123 0.275 0.659 0.760 1.032 1.174 1.253 1.071

0.142 0.317 0.758 0.874 1.187 1.350 1.441 1.232

0.156 0.348 0.834 0.962 1.306 1.485 1.585 1.355

0.113 1.012 3.496 4.145 5.843 6.589 6.998 5.836

0.013 0.117 0.406 0.481 0.678 0.764 0.812 0.677

0.016 0.147 0.507 0.601 0.847 0.955 1.015 0.846

0.019 0.169 0.583 0.691 0.974 1.099 1.167 0.973

0.021 0.186 0.641 0.760 1.072 1.209 1.284 1.070

-1.402 -0.814 1.340 1.886 3.218 3.498 3.616 2.643

-0.163 -0.094 0.155 0.219 0.373 0.406 0.419 0.307

-0.203 -0.118 0.194 0.273 0.467 0.507 0.524 0.383

-0.234 -0.136 0.223 0.314 0.537 0.583 0.603 0.441

-0.257 -0.149 0.246 0.346 0.590 0.642 0.663 0.485

3.148 3.033 3.721 4.486 5.1 5.542 6.451 7.596

31 28 31 30 31 30 31 31

97.588 84.924 115.351 134.58 158.1 166.26 199.981 235.476

5.939 3.701 4.445 4.157 1.756 1.180 -0.034 0.359

184.109 103.628 137.795 124.71 54.436 35.4 -1.054 11.129

0.73 0.73 0.73 0.73 0.73 0.73 0.73 0.73

134.39957 75.64844 100.59035 91.0383 39.73828 25.842 -0.76942 8.12417

1 1 1 1 1 1 1 1

4.148 4.033 4.721 5.486 6.1 6.542 7.451 8.596

4.33547 2.70173 3.24485 3.03461 1.28188 0.8614 -0.02482 0.26207

1.574 1.5165 1.8605 2.243 2.55 2.771 3.2255 3.798

1.85732 1.78947 2.19539 2.64674 3.009 3.26978 3.80609 4.48164

3.02208 2.91168 3.57216 4.30656 4.896 5.32032 6.19296 7.29216

3.3054 3.18465 3.90705 4.7103 5.355 5.8191 6.77355 7.9758

3.21096 3.09366 3.79542 4.57572 5.202 5.65284 6.58002 7.74792

2.677 3.433 2.553 2.596 2.467 2.56 3.039 3.687

JAN FEB MAR APR MEI JUN JUL AGT

3.33 3.33 3.33 3.33 3.33 3.33 3.33 3.33

-1.00547 0.62827 0.08515 0.29539 2.04812 2.4686 3.35482 3.06793

-0.1166345 0.07287932 0.0098774 0.03426524 0.23758192 0.2863576 0.38915912 0.35587988

NOV DES

( K ) ( L ) JAN PEB MAR APR

5.610 3.474 3.120 3.062 3.723 4.486

6.171 3.821 Eo 3.4314548101 3.3677905 4.0952383 4.9344513

2.289 4.919 M = Eo + P 4.4314548101 4.3677905 5.0952383 5.9344513

k = MT / S 1.329436443 1.3103372 1.5285715 1.7803354

3.085 1.911 3.7789131545 3.7074235 4.6115844 5.9318455

4.628 2.8666.0261267425 5.9810551 6.5060424 7.1377435

6.171 3.821

6.171 3.821

5.060 3.133

2.777 1.719

8.115 6.306

5.826 1.386

0.676 0.161

0.845 0.201

0.971 0.231

1.069 0.254

0.796 -3.009

0.092 -0.349

0.115 -0.436

0.133 -0.502

0.146 -0.552

2.339 -2.054

0.271 -0.238

0.339 -0.298

0.390 -0.342

0.429 -0.377

3.882 -1.098

0.450 -0.127

0.563 -0.159

0.647 -0.183

0.712 -0.201

3.882 -1.098

0.450 -0.127

0.563 -0.159

0.647 -0.183

Eto (dari Penman)

ek

1

x

k

k

e

eMIR

0.712 -0.201

2.771 -1.786

0.321 -0.207

0.402 -0.259

0.462 -0.298

0.508 -0.328

0.488 -3.200

0.057 -0.371

0.071 -0.464

0.081 -0.534

0.089 -0.587

52.241

30

1567.23

0.682

20.46

0.73

14.9358

1

53.241

0.49786

26.1205

30.82219

50.15136

54.85305

53.28582

3.848

SEP

3.33

2.83214

0.32852824

MEI JUN JUL AGU SEP OKT NOV DES Keterangan

5.297 5.550 6.451 7.596 8.310 7.845 5.610 3.474 (mm/hari)

5.8265925 6.1053309 7.0956615 8.3554588 9.1414236 8.6291907 6.1709216 3.8210438 Eo 1,10

6.8265925 7.1053309 8.0956615 9.3554588 10.141424 9.6291907 7.1709216 4.8210438 P 1,00

2.0479777 2.1315993 2.4286985 2.8066377 3.0424271 2.8887572 2.1512765 1.4463132 T 15,00

7.7522083 8.4283352 11.344108 16.554164 20.956044 17.970962 8.5958239 4.247426 S 50,00

7.8376088 8.0618482 8.8782966 9.956935 10.649612 10.196583 8.1149827 6.3056177 mm/hari

Keterangan

(mm/hari)

Eto

mm/hari

hari

mm

mm/hari

PERHITUNGAN KEBUTUHAN AIR IRIGASI

TANAMAN PADI (120 HARI) OKT NOV DES JAN

EVAPORASI (Eo) 7.845 5.610 3.474 3.120

PERKOLASI (P) 1.000 1.000 1.000 1.000

Eo + P 8.845 6.610 4.474 4.120

Rh=Hujan ( 1 in 5 dry ) = Xt / jmlh hari 1.699 3.136 6.739 5.939

1 0.18 0.306 0.564 1.213 1.0692 0.53 0.900 1.662 3.572 3.148

3 0.55 0.934 1.725 3.706 3.266

4 0.4 0.680 1.254 2.696 2.3765 0.4 0.680 1.254 2.696 2.3766 0.4 0.680 1.254 2.696 2.3767 0.4 0.680 1.254 2.696 2.376

8 0.2 0.340 0.627 1.348 1.1881 1.1 8.629 6.171 3.821 3.4312 1.1 8.629 6.171 3.821 3.4313 1.05 8.237 5.890 3.647 3.2754 1.05 8.237 5.890 3.647 3.2755 0.95 7.452 5.329 3.300 2.9646 0 0.000 0.000 0.000 0.000

LP1 ( tabel 1a) 14.055 12.427 10.975 10.745LP1 - Re1 = A = Ir 13.749 11.862 9.762 9.675A x 0,116 = B 1.595 1.376 1.132 1.122B x 1,25 = C 1.994 1.720 1.415 1.403C x 1,15 = D 2.293 1.978 1.628 1.613D x 1,10 = E 2.522 2.176 1.791 1.775LP2 ( tabel 1a) 14.055 12.427 10.975 10.745LP1 - Re2 = A = Ir 13.155 10.765 7.403 7.597A x 0,116 = B 1.526 1.249 0.859 0.881B x 1,25 = C 1.907 1.561 1.073 1.102C x 1,15 = D 2.194 1.795 1.235 1.267D x 1,10 = E 2.413 1.975 1.358 1.393Et1 + P + W - Re3 = A = Ir 12.025 8.776 4.445 4.495A x 0,116 = B 1.395 1.018 0.516 0.521B x 1,25 = C 1.744 1.273 0.644 0.652C x 1,15 = D 2.005 1.463 0.741 0.750D x 1,10 = E 2.206 1.610 0.815 0.824Et2 + P + W - Re4 = A = Ir 12.280 9.247 5.455 5.386A x 0,116 = B 1.424 1.073 0.633 0.625B x 1,25 = C 1.781 1.341 0.791 0.781C x 1,15 = D 2.048 1.542 0.910 0.898D x 1,10 = E 2.252 1.696 1.001 0.988

Factor Hujan dengan 2

golongan (FH) tiap 2 mingguan

Effective Rainfall Re = hujan x FH

Koefesien Tanaman (Kt)

Evapotranspirasi Et = Eo x kt

Re kel.1 Pengolahan tanah untuk tanaman padi

kejenuhan 200 mm minggu I

Re kel.1 Pengolahan tanah untuk tanaman padi

kejenuhan 200 mm minggu I

Pertumbuhan ke-2 Minggu I, Re ke-3, ET ke-1. w =

3.3333

Pertumbuhan ke-2 Minggu II, Re ke-4, ET ke-2. w =

3.3333

TANAMAN PADI (120 HARI) OKT NOV DES JANEt3 + P + W - Re5 = A = Ir 11.887 8.966 5.282 5.230A x 0,116 = B 1.379 1.040 0.613 0.607B x 1,25 = C 1.724 1.300 0.766 0.758C x 1,15 = D 1.982 1.495 0.881 0.872D x 1,10 = E 2.180 1.645 0.969 0.959Et4 + P + W - Re6 = A = Ir 11.887 8.966 5.282 5.230A x 0,116 = B 1.379 1.040 0.613 0.607B x 1,25 = C 1.724 1.300 0.766 0.758C x 1,15 = D 1.982 1.495 0.881 0.872D x 1,10 = E 2.180 1.645 0.969 0.959Et5 + P - Re7 = A = Ir 7.773 5.075 1.604 1.588A x 0,116 = B 0.902 0.589 0.186 0.184B x 1,25 = C 1.127 0.736 0.233 0.230C x 1,15 = D 1.296 0.846 0.268 0.265D x 1,10 = E 1.426 0.931 0.294 0.291Et6 + P - Re8 = A = Ir 0.660 0.373 -0.348 -0.188A x 0,116 = B 0.077 0.043 -0.040 -0.022B x 1,25 = C 0.096 0.054 -0.050 -0.027C x 1,15 = D 0.110 0.062 -0.058 -0.031D x 1,10 = E 0.121 0.068 -0.064 -0.034

Keterangan :0,116 : Angka konversi (mm/hari)1,25 : Kehilangan di saluran petak tersier 25 %1,15 : Kehilangan di saluran petak sekunder 15 %1,10 : Kehilangan di bendung, bangunan bagi (saluran primer) 10 %C : Kehilangan air di saluran TersierD : Kehilangan air di saluran SekunderE : Kehilangan air di saluran Primer

Pertumbuhan ke-2 Minggu III, Re ke-5, ET ke-3. w =

3.3333

Pertumbuhan ke-2 Minggu IV, Re ke-6, ET ke-4. w =

3.3333

Pertumbuhan ke-2 Minggu V, Re ke-7, ET ke-5. w =

3.3333

Pertumbuhan ke-2 Minggu VI, Re ke-8, ET ke-6. w =

3.3333

PERHITUNGAN KEBUTUHAN AIR IRIGASI

FEB MAR APR MEI JUNI JULI AGT SEP KETERANGAN

3.062 3.723 4.486 5.297 5.550 6.451 7.596 8.310

1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000

4.062 4.723 5.486 6.297 6.550 7.451 8.596 9.310

3.701 4.445 4.157 1.756 1.180 0.000 0.359 0.682

0.666 0.800 0.748 0.316 0.212 0.000 0.065 0.1231.962 2.356 2.203 0.931 0.625 0.000 0.190 0.361

2.036 2.445 2.286 0.966 0.649 0.000 0.197 0.375

1.480 1.778 1.663 0.702 0.472 0.000 0.144 0.2731.480 1.778 1.663 0.702 0.472 0.000 0.144 0.2731.480 1.778 1.663 0.702 0.472 0.000 0.144 0.2731.480 1.778 1.663 0.702 0.472 0.000 0.144 0.273

0.740 0.889 0.831 0.351 0.236 0.000 0.072 0.1363.368 4.095 4.934 5.827 6.105 7.096 8.355 9.1413.368 4.095 4.934 5.827 6.105 7.096 8.355 9.1413.215 3.909 4.710 5.562 5.828 6.773 7.976 8.7263.215 3.909 4.710 5.562 5.828 6.773 7.976 8.7262.909 3.537 4.262 5.032 5.273 6.128 7.216 7.895

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.00010.707 11.139 11.650 12.208 12.385 13.026 13.868 14.40810.041 10.339 10.902 11.891 12.172 13.026 13.804 14.2851.165 1.199 1.265 1.379 1.412 1.511 1.601 1.6571.456 1.499 1.581 1.724 1.765 1.889 2.002 2.0711.674 1.724 1.818 1.983 2.030 2.172 2.302 2.382

1.842 1.896 2.000 2.181 2.233 2.389 2.532 2.62010.707 11.139 11.650 12.208 12.385 13.026 13.868 14.4088.746 8.783 9.447 11.277 11.759 13.026 13.678 14.0471.014 1.019 1.096 1.308 1.364 1.511 1.587 1.6291.268 1.274 1.370 1.635 1.705 1.889 1.983 2.0371.458 1.465 1.575 1.880 1.961 2.172 2.281 2.342

1.604 1.611 1.733 2.068 2.157 2.389 2.509 2.5765.662 5.980 6.978 9.191 9.786 11.426 12.488 13.0960.657 0.694 0.809 1.066 1.135 1.325 1.449 1.5190.821 0.867 1.012 1.333 1.419 1.657 1.811 1.8990.944 0.997 1.164 1.533 1.632 1.905 2.082 2.184

1.039 1.097 1.280 1.686 1.795 2.096 2.291 2.4026.217 6.647 7.602 9.454 9.963 11.426 12.542 13.1990.721 0.771 0.882 1.097 1.156 1.325 1.455 1.5310.902 0.964 1.102 1.371 1.445 1.657 1.819 1.9141.037 1.108 1.268 1.576 1.661 1.905 2.091 2.201

1.140 1.219 1.394 1.734 1.828 2.096 2.300 2.421

Hasil Perhitungan (mm/hari)

Effective Rainfall Factors Tabel 1.b.

(mm/hari)

Crop Coeficients for Rice (FAO) varietas unggul

Tabel 1.c. (mm/hari)

Tabel Zylstra Berdasarkan Eo+P

(mm/hari)

w = 3,33 mm/hari kebutuhan air untuk

penggantian air genangan pada saat

pemupukan

FEB MAR APR MEI JUNI JULI AGT SEP KETERANGAN6.064 6.461 7.377 9.189 9.686 11.103 12.162 12.7830.703 0.749 0.856 1.066 1.124 1.288 1.411 1.4830.879 0.937 1.070 1.332 1.404 1.610 1.763 1.8541.011 1.077 1.230 1.532 1.615 1.851 2.028 2.132

1.112 1.185 1.353 1.686 1.777 2.037 2.231 2.3456.064 6.461 7.377 9.189 9.686 11.103 12.162 12.7830.703 0.749 0.856 1.066 1.124 1.288 1.411 1.4830.879 0.937 1.070 1.332 1.404 1.610 1.763 1.8541.011 1.077 1.230 1.532 1.615 1.851 2.028 2.132

1.112 1.185 1.353 1.686 1.777 2.037 2.231 2.3452.428 2.759 3.599 5.330 5.801 7.128 8.072 8.6220.282 0.320 0.417 0.618 0.673 0.827 0.936 1.0000.352 0.400 0.522 0.773 0.841 1.034 1.171 1.2500.405 0.460 0.600 0.889 0.967 1.189 1.346 1.438

0.445 0.506 0.660 0.978 1.064 1.307 1.481 1.5820.260 0.111 0.169 0.649 0.764 1.000 0.928 0.8640.030 0.013 0.020 0.075 0.089 0.116 0.108 0.1000.038 0.016 0.024 0.094 0.111 0.145 0.135 0.1250.043 0.019 0.028 0.108 0.127 0.167 0.155 0.144

0.048 0.020 0.031 0.119 0.140 0.183 0.170 0.158

A = mm/hari B = lt/dt C = lt/dt D = lt/dt E = lt/dt

JAN PEB MAR APR MEI JUN JUL AGU

3.1195044 3.0616278 3.7229439 4.4858648 5.2969023 5.5503008 6.4506014 7.5958717

Eo 3.4314548 3.3677905 4.0952383 4.9344513 5.8265925 6.1053309 7.0956615 8.3554588

4.4314548 4.3677905 5.0952383 5.9344513 6.8265925 7.1053309 8.0956615 9.3554588

0.5317746 0.5241349 0.6114286 0.7121342 0.8191911 0.8526397 0.9714794 1.1226551

1.7019499 1.688997 1.8430625 2.0383367 2.268664 2.345831 2.6418499 3.0730024

IR 10.744519 10.707137 11.138964 11.649795 12.207523 12.384843 13.026479 13.868458

Eto (dari Penman)

M = Eo + P k = MT / S

ek

SEP OKT NOV DES Keterangan

8.3103851 7.8447188359 5.6099287685 3.473676226(mm/hari)

9.1414236 8.6291907194 6.1709216453 3.8210438486 Eo 1,10 Eto

10.141424 9.6291907194 7.1709216453 4.8210438486 P 1,00 mm/hari

1.2169708 1.1555028863 0.8605105974 0.5785252618 T 30,00 hari

3.3769429 3.1756199919 2.3643676256 1.7834064329 S 250,00 mm

14.408006 14.055143209 12.426779019 10.974993632 mm/hari

TABEL KEBUTUHAN AIR IRIGASI

ANGKA KEBUTUHAN OKT NOV DES JAN

GOLONGAN I OKTOBER DUA MINGGU TERAKHIR

BERO Pola Tanam Padi ILP 1 LP 2 1 2 3 4

Saluran Tersier ( C ) 1.993652 1.560881 1.272538 0.791039 0.765855 0.758333Saluran Sekunder ( D ) 2.2927 1.795014 1.463418 0.909695 0.880733 0.872082

Saluran Primer ( E ) 2.52197 1.974515 1.60976 1.000665 0.968807 0.959291

GOLONGAN II NOVEMBER DUA MINGGU PERTAMA

BERO Pola Tanam Padi I6 LP 1 LP 2 1 2 3

Saluran Tersier ( C ) 0.383216 1.720033 1.560881 0.644466 0.791039 0.758333Saluran Sekunder ( D ) 0.440698 1.978038 1.795014 0.741136 0.909695 0.872082

Saluran Primer ( E ) 0.484768 2.175842 1.974515 0.81525 1.000665 0.959291

ANGKA KEBUTUHAN RATA - RATA

RATA - RATA ( C ) 0.191608 0.996826 1.640457 1.416709 0.717753 0.778447 0.758333RATA - RATA ( D ) 0.220349 1.14635 1.886526 1.629216 0.825416 0.895214 0.872082

RATA - RATA ( E ) 0.242384 1.260985 2.075179 1.792138 0.907957 0.984736 0.959291

KeteranganC : Kehilangan air di saluran TersierD : Kehilangan air di saluran SekunderE : Kehilangan air di saluran Primer

Pola Tanam : Padi - Padi - BeroGolongan I : Saluran induk KananGolongan II : Saluran induk Kiri


JAN FEB MAR APR MEI JUN


Pola Tanam Padi I Pola Tanam Padi II5 6 LP 1 LP 2 1 2 3 4 5 6

0.23025 0.037671 1.455939 1.273551 0.867171 1.102239 1.069717 1.332455 0.7728 0.110780.264787 0.043322 1.67433 1.464584 0.997246 1.267575 1.230174 1.532324 0.88872 0.127397

0.291266 0.047654 1.841762 1.611043 1.096971 1.394333 1.353192 1.685556 0.977592 0.140137


Pola Tanam Padi I Pola Tanam Padi II4 5 6 LP 1 LP 2 1 2 3 4 5

0.758333 0.352081 0.037671 1.499135 1.273551 1.011825 1.102239 1.332455 1.332455 0.8411140.872082 0.404893 0.043322 1.724006 1.464584 1.163598 1.267575 1.532324 1.532324 0.967281

0.959291 0.445383 0.047654 1.896406 1.611043 1.279958 1.394333 1.685556 1.685556 1.064009

ANGKA KEBUTUHAN RATA - RATA

0.494291 0.194876 0.746805 1.386343 1.070361 1.057032 1.085978 1.332455 1.052628 0.4759470.568435 0.224108 0.858826 1.594295 1.230915 1.215587 1.248875 1.532324 1.210522 0.547339

0.625278 0.246518 0.944708 1.753724 1.354007 1.337146 1.373762 1.685556 1.331574 0.602073

`


JUN JUL AGT SEP KETERANGAN


Pola Tanam PalawijaLP 1 2 3 4 5 6

1.044065 0.518034 0.775252 1.173541 1.173541 1.014726 0.5242881.200675 0.59574 0.89154 1.349573 1.349573 1.166934 0.602931

1.320742 0.655313 0.980694 1.48453 1.48453 1.283628 0.663225


Pola Tanam Padi II Pola Tanam Palawija6 LP 1 2 3 4 5

0.11078 1.290952 0.518034 0.870656 1.173541 1.253317 1.0147260.127397 1.484595 0.59574 1.001254 1.349573 1.441314 1.166934

0.140137 1.633054 0.655313 1.10138 1.48453 1.585446 1.283628

ANGKA KEBUTUHAN RATA - RATA MAKS.

0.577422 0.904493 0.646643 1.022099 1.173541 1.134021 0.769507 C = 1,64 lt/dt/ha0.664036 1.040167 0.74364 1.175413 1.349573 1.304124 0.884933 D = 1,89 lt/dt/ha

0.730439 1.144184 0.818004 1.292955 1.48453 1.434537 0.973426 E = 2,075 lt/dt/ha

Golongan I Dua Minggu Terakhir Bulan Oktober LP = 30 hari Pertumbuhan 120 hariGolongan II Dua Minggu Pertama Bulan November LP = 30 hari Pertumbuhan 120 hari

Evapotranspirasi Dan Kebutuhan Air

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