Economics of irrigation
The economics of crop production with different irrigation sources was worked out to compare
the economic feasibility of irrigation investment with existing and improved technologies.
Different irrigation technologies, input and output prices and break-even yields could be
important to justify the future of irrigation technology transfer and uptake.
Tanzania
The cost of irrigation per hectare varies from system to system. In the case of the traditional
gravity system the annual (fixed) cost per hectare was US$ 16 compared to US$ 43/ha in the
case of the improved gravity system (Table 1).
Total cost of irrigation per hectare was US$ 26 for maize, US$ 27 for beans and US$ 38 for
paddy under traditional gravity system and was US$ 53, US$ 55 and US$ 69 respectively under
improved gravity systems (Table 1).
In the case of the manually operated treadle pump the annual cost per hectare was US$ 49
compared with US$ 212 for diesel and US$ 152 for electric powered pumps (Table 2).
Total cost of irrigation per hectare with 100 percent crop intensity was US$ 126 with the
treadle pump, US$ 306 with a diesel pump and US$ 190 with an electric pump for maize. The
costs were US$ 268, US$ 306 and US$ 229 for beans with the treadle, diesel and electric
pumps respectively (Table 2).
In the case of paddy, the costs were US$ 227, US$ 436 and US$ 305 respectively with the
treadle, diesel and electric pumps. Since farmers normally go for two crops (i.e., at least 150%
crop intensity), the profitability will be even higher.
Irrigated yields are almost two times higher than the rainfed yields. The average yield of
irrigated maize and paddy are about 2.5 t/ha and 3.5 t/ha respectively (Table 3).
Gross margin analyses indicate that beans are comparatively more profitable than maize and
paddy. Irrigated crops yield almost four times higher gross margins than rainfed crops.
However, paddy is remunerative in view of the higher crop value. Given the food security goals,
irrigated maize is still a profitable option (Table 3).
Break-even crop yields indicate the safety margin in irrigated agriculture as average yields are
almost 1.5 times higher than the break-even yields. Even with price or yield fluctuations farmers
are able to manage that level of crop production.
TABLE 1 Cost of irrigation under gravity irrigation types (diversion schemes) in Tanzania
Costs Traditional gravity Improved gravity
Capital cost ($) 4145 16582
Average coverage (ha) 51 65
Life period (yrs) 10 15
Irrigation cost ($/ha):
a. annual capital cost ($/ha) 16.28 43.67
b. maintenance cost ($/ha) (3% of capital cost) 0.50 1.30
c. labour cost ($/ha): wet season
1. maize 9.10 8.18
2. beans 10.00 10.00
3. paddy 20.90 24.54
d. Total irrigation cost ($/ha)
1. maize 25.88 53.15
2. beans 26.78 54.97
3. paddy 37.68 69.51
TABLE 2 Cost of irrigation under different pumping technologies in Tanzania
Mechanical power
Items Manual power Treadle pump
Diesel Electric
Capital cost ($) 100 1025 736
Average coverage (ha) 0.4 2 2
Life period (Yrs) 5 10 10
Irrigation cost ($/ha):
a. annual capital cost ($/ha): 49.11 212.17 152.35
b. maintenance cost 5 21 15
(10% of capital cost)
c. labour cost ($/ha):
1. maize 72.18 22.7 22.7
2. beans 88.18 22.82 22.82
3. paddy 173.18 246.45 244.54
d. energy cost ($/ha):
1. maize - 50.18 39.27
2. beans - 50.18 39.27
3. paddy - 156.36 92.82
e. Total irrigation cost ($/ha/year):
1. maize 126.29 306.07 190.07
2. beans 268.58 306.07 229.44
3. paddy 227.29 435.98 304.71
TABLE 3 Economics of crop production in Tanzania
Total Total Break-even Gross Gross
Yield Price
Crap cost (US revenue yield margin margin/plot
(kg/ha) (US$/ha)
$) (US$/ha) (Kg/ha) <US$/ha) (US$)
Maize
109.2 1100 0.15 165 728 55.8 1395
(rainfed)
Maize
177.8 2550 0.15 382.5 1185 204.7 51.2
(irrigated)
Beans
140.5 400 0.64 256 220 115.5 28.9
(rainfed)
Beans
214.3 980 0.64 627.2 335 412.9 103.2
(irrigated)
Paddy
286.9 3550 0.15 532.5 1912 245.6 61.4
(irrigated)
TABLE 4 Investment cost of different pumping technologies in Malawi
Human power R & W Mechanical power Treadle With sprinkler
Items
pump pump Diesel Electric
Capital cost ($) 60 100 1040 750
Average coverage (ha) 0.25 0.4 2.0 2.0
Life period (Yrs) 5 5 10 10
Irrigation cost ($/year):
a. annual capital cost ($) 32 53 240 173
b. annual sprinkler cost - - 904 904
($)
Note: Cost of sprinkler system will be $ 1 500 -2000. Life period will be 20 years. Replacement
cost of sprinkler heads will be $ 60/ha after 10 years; Replacement cost of sprinkler hoses will
be $ 72/ha every 5 years.
Malawi
In the case of rope and washer pumps, the annual cost per hectare was US$ 32 compared to
US$ 53 in the case of the treadle pump. For mechanical equipment, the annual cost per hectare
is US$ 240 and US$ 173 with diesel and electric pumps respectively (Table 4).
Since the cost of irrigation was worked out with sprinkler systems, this cost is comparatively
higher than the manual systems. Total cost of irrigation per hectare for maize with 100 percent
cropping intensity was US$ 254 with rope and washer and US$ 231 with the treadle pump, US$
1 576 with the diesel pump and US$ 1 393 with the electric pump. The costs were US$ 258,
US$ 242, US$ 1651 and US$ 1 448 for beans respectively with the above systems. For
cabbage, the costs were US$ 265, US$ 272, US$ 1 659 and US$ 1 454 respectively with the
above irrigation sources. Since farmers normally go for two crops (i.e., at least 150 percent crop
intensity), the profitability will be higher still (Table 5).
Gross margin analyses indicate that vegetables are comparatively more profitable than maize.
Average gross margin per hectare ranged from US$ 48 for rainfed maize to US$ 1 283 for
irrigated maize. For beans, it was US$ 879, onion US$ 2 270 and for cabbage
Break-even crop yields indicate the safety margin in irrigated agriculture. For vegetables,
average yields are almost 2.5 times higher than the break-even yields. Even with price or yield
fluctuations farmers can manage that level of crop production.
TABLE 5 Cost of irrigation with varying technologies in Malawi
Human power Mechanical power
Items
R & W pump Treadle Diesel Electric
1. Fixed cost ($/ha) 128 132 240 173
With sprinkler - - 1144 1077
2. Variable cost:
i. maintenance cost 13 13 24 17
ii. labour cost ($/ha)
1. maize 113 86 22 22
2. beans 117 97 25 25
3. onions 154 154 30 30
4. cabbage 124 127 27 27
iii. energy cost ($/ha)
1. maize - - 146 104
2. beans - - 218 156
3. onion - - 350 250
4. cabbage - - 224 160
c. Total irrigation cost (100 % crop intensity) ($/ha/year)
1. maize 254 231 1576 1393
2. beans 258 242 1651 1448
3. onion 295 299 1788 1547
4. cabbage 265 272 1659 1454
Notes: 1. Fuel consumption will be about 0.3 lit/HP-hr and lubrication oil cost will be about 10% of the
fuel cost. Total hours of pumping per ha. will be about 104 hrs for maize; 156 hrs for beans; 250
hrs for onion; 160 hrs for cabbage. Diesel costs $ 0.56/litre.
2. R & W indicates rope and washer pump.
TABLE 6 Economics of crop production in Malawi
Total Total Gross, Gross
Yield Price Break-even
Crop cost revenue margin margin/plot
(kg/h) (US$/kg) yield (kg/ha)
(US$) (US$/h) (US$/ha) (US$)
Maize
56.3 950 0.11 104.5 512 48.2 12.1
(rainfed)
Maize
531.9 5500 0.33 1815 1612 1283.1 320.8
(irrigated)
Beans
520.7 2000 0.7 1400 744 879.3 219.8
(irrigated)
Onion
1387.8 10450 0.35 3657.5 3965 2269.9 567.5
(irrigated)
Cabbage 1178.9 17500 0.20 3500 5894 2321.1 580.3
Zambia
Cost of irrigation per hectare varies with the system used. In the case of traditional surface
system the annual (fixed) cost per hectare was US$ 585 compared to US$ 218/ha with the
rehabilitation system (Table 7).
Total cost of irrigation (fixed and variable costs) was US$ 613 for maize, US$ 620 for tomato
and is US$ 618 for onion with the traditional surface system and US$ 235 for maize, US$ 242
for tomato and US$ 240/ha for onion with the improved system (Table 7).
For the manually operated treadle pump, the annual cost was US$ 85/ha and is US$ 258 for
diesel and US$ 181 for electric powered pumps (Table 8).
Total cost of irrigation was US$ 156/ha with the treadle pump, US$ 320/ha with the diesel
pump and US$ 223 with the electric pump for maize at 100 percent crop intensity. The costs are
US$ 182, US$ 323 and US$ 222/ha respectively for tomato with the treadle, diesel and electric
pumps respectively at 100% crop intensity. Since farmers normally go for two crops (i.e., at
least 150% crop intensity), the profitability will be higher still (Table 8).
Gross margin analyses indicate that vegetables are comparatively more profitable than maize
and paddy. However, paddy is remunerative in view of the higher value of the crop. Given the
food security goals, irrigated maize is still profitable (Table 9).
Break-even crop yields indicate the safety margin in irrigated agriculture. Even with price or
yield fluctuations farmers are able to manage that level of crop production (Table 9).
TABLE 7 Cost of irrigation under surface systems in Zambia
Costs Traditional gravity Improved gravity
Capital cost ($) 2080 4850
Average coverage (ha) 160 10
Life period (yrs) 20 20
Irrigation cost ($/ha):
a. annual capital cost ($/ha) 585 218
b. maintenance cost ($/ha) 18 7
(3% of capital cost)
c. labour cost ($/ha):
1. maize 10.80 10.80
2. tomato 17.44 17.44
3. onion 15.20 15.20
d. Total irrigation cost ($/ha)
e. (100% crop intensity)
maize 613.80 235.80
tomato 620.44 242.44
onion 618.20 240.20
Note: For new system completion, cost estimates for Mulumbi system were used where the
main system will cost about $ 250/ha and tertiary development about $ 1 050/ha. For
rehabilitation, data for Nkandabwe were used for computation where the main system
rehabilitation will cost about $ 125/ha and tertiary system repairs will cost about $ 360/ha.
Zimbabwe
Cost of irrigation per hectare was worked out for various pumping technologies, namely,
sprinkler, drip and surface irrigation systems. Further, cost of irrigation with 'collector wells' was
also analysed for financial viability.
Data from the Hama Mavhaire irrigation system were used to analyse the cost of irrigation with
sprinkler irrigation. Data from the Mushandike irrigation system were used to analyse the
irrigation cost with the gravity system. Data from the collector well installed in Zaka were used to
analyse the irrigation cost with that system. The cost of drip irrigation was computed taking into
account yield differences observed between drip and other irrigation types at the Chiredzi
research station. In general, for vegetables, a minimum of 20 percent higher yield was observed
with drip compared to sprinkler irrigation. In all cases, data for 1995-96 were used.
Productive life periods assumed in the analysis were: dam 40 years; scheme canals 20 years;
pumping unit 15 years; sprinkler head and pipes 20 years; drag-hose 6 years; collector well 15
years two hand pumps were used in the collector well and life was assumed to be 8 years.
Interest rate was 12%. Efficiencies of the systems were as follows: sprinkler 75%; drip 85%;
gravity 45% and manual irrigation from collector well 65%. Pump efficiency was 70%. Average
cost of electricity was US$ 0.05/kwh or US$ 18/megalitre. Average cost of water from collector
wells was about US$ 0.36/m3.
Total irrigation costs (annual and variable costs, excluding labour and energy costs) was US$
1 518/ha for the sprinkler system; US$ 1 417/ha for the drip irrigation system; US$1 520/ha with
the surface system and US$ 2 494/ha with the collector well system (Table 10)
Total irrigation costs (including labour and energy costs) was US$ 1 654/ha with sprinkler
irrigation; US$ 1 553/ha with drip system; US$1 600/ha under gravity system and US$2 752/ha
with collector well. Even though farmers use sprinkler and drip systems with 250 to 300 percent
crop intensity, a conservative estimate of 200 percent was used in the analysis for all the
irrigation types (Table 10).
Import and export parity prices were used in the gross margin calculations for maize and
wheat crops. The export parity price for maize was US$ 0.15/kg and for wheat, the import parity
price was US$ 0.27/kg. Total gross margin was US$ 1 840/ha with sprinkler; US$ 2 219/ha with
drip system; $1 821/ha with surface system and $2 635/ha with collector well (Table 11).
In the case of 'collector wells' even though the area irrigated was about 0.5 ha, the well also
serves as a drinking water source for about 600 people in the rural area who consumed about
13 litres/person/day. Average cost was US$ 0.35/m3. If two boreholes are drilled and two hand
pumps installed, the cost would be about US$ 0.42/m3, whereas a single borehole with
motorized pump, would cost US$ 0.38/m3. However, the success rate was less than 50 percent
in the latter two cases. Hence, the viability of the scheme based on the gross margin from the
community gardens could not be judged for the collector well.
In the case of smallholder schemes, besides financial viability, other benefits such as
employment generation, improved nutritional standards and improved market activities
associated with forward and backward linkages are also common. These benefits can further
justify the rationale for smallholder irrigation investment.
Break-even crop yields indicate the safety margin in irrigated agriculture. Even with price or
yield fluctuations (risks) farmers can manage that level of crop production.
TABLE 8 Cost of irrigation under different pumping technologies in Zambia
Mechanical power
Items Manual power Treadle pump
Diesel Electric
Capital cost ($) 160 1125 786
Average coverage (ha) 0.4 2.0 2.0
Life period (yrs) 5 10 10
Irrigation cost ($/ha):
a. annual capital cost ($/ha) 85 258 181
b. maintenance cost 8.5 25.8 18.1
(10% of capital cost)
c. labour cost ($/ha):
1. maize 62.18 19.80 19.80
2. tomato 88.18 17.44 17.44
3. onion 76.12 16.20 16.20
d. energy cost ($/ha):
1. maize - 16.34 4 22
2. tomato - 32.16 5.70
3. onion - 32.16 5.70
e. Total irrigation cost ($/ha/year): (100 % crop intensity)
1. maize 155.68 319.94 223.12
2. tomato 333.40 222.24 181.68
3. onion 169.62 332.16 221.00
Note: Capital cost also includes the well drilling based on cheaper drilling technologies which
accounts for roughly one-third of the capital cost. Maintenance cost will be about 10% of annual
capital cost. Fuel consumption will be about 0.3 lit/HP-hr and lubrication oil cost will be about
10% of the fuel cost. Average cost of diesel will be about $ 0.25 per litre and electricity costs
about $ 0.016/kwh. Even though the interest rate varies up to 60%, only 45% is used for
computation.
TABLE 9 Economics of crop production in Zambia
Total Total Gross Gross
Yield Price Break-even
Crop cost revenue margin margin/plot
(kg/ha) (US$/kg) yield (kg/ha)
(U$) (US$/ha) (US$/ha) (US$)
Maize
124.7 1750 10.12 210 1039 85.3 21.3
(rainfed)
Paddy
146.8 760 0.30 228 489 81.2 57.0
(rainfed)
Cotton
121.6 700 0.22 154 553 32.4 8.1
(rainfed)
Maize
172.5 5300 0.12 636 1438 463.5 115.9
(irrigated)
Tomato
314.6 7500 0.13 975 2420 660.4 165.1
(irrigated)
Onion
615.5 8550 0.21 1795.5 2931 1180 295
(irrigated)
Cabbage 509.1 9800 0.16 1568 3181 1058.9 264.7
rape 250.8 4200 0.24 1008 1045 757.2 189.3
Paddy
328.4 4200 0.30 1260 1095 931.6 232.9
(irrigated)
TABLE 10 Cost of irrigation under different pumping technologies in Zimbabwe
Items Sprinkler system Drip system Gravity system Collector well
Capital cost ($)
a. Dam 940295 940295 5330526 -
b. Well - - 7020
c. Scheme/equipment 202105 303158 1582500 912
Area covered (ha) 96 115 633 0.5
Irrigation cost ($/year):
a. annual capital cost ($/ha/year) 1175 981 1010
1. Dam 2050
2. Well 309 338 438 368
3. Scheme/structure
b. Maintenance cost ($/ha/year) 34 48 72 76
c. Energy cost ($/ha) 62 62 - -
d. Labour cost ($/ha) 7 7 40 129
e. Total irr. Cost ($/ha/year) 1654 1553 1600 2752
f. Gross margin ($/ha/year) 1840 2219 1821 2635
Assumptions: Life periods assumed are: dam 40 years; scheme canals 20 years; pumping unit
15 years; sprinkler head & pipes 20 years and drag-hose 4 years; collector well 1 5 years; two
hand pumps used in collector well and life will be 8 years. Interest rate 12%. Efficiency of
sprinkler system 75%; drip system 85%; gravity system 45% and manual irrigation from
collector well 65%. Pump efficiency 70%. Average cost of electricity $ 0.05/kwh or $ 1
8/megalitre. Average cost of water from collector well will be about $ 0.35/m3.
TABLE 11 Economics of crop production in Zimbabwe
Total Total Break-even Gross Gross
Yield Price
Crop cost; revenue yield margin margin/plot
(kg/ha) (US$/kg)
(US$) (US$/ha) (kg/ha) (US$/ha) (US$)
Maize
264.3 7400 0.15 1110 1762 845.7 211.4
(sprinkler)
Ground nut
258.1 2740 0.31 849.4 832 591.3 147.8
(sprinkler)
Sugar bean
363.3 1940 0.7 1358 518 994.7 248.7
(sprinkler)
Cotton
432 2100 0.61 1281 635 849 212.3
(surface)
Wheat
511.6 4000 0.27 1080 1894 568.4 250.1
(surface)
Green maize
454.7 9600 0.15 1440 3031 985.3 246.3
(surface)
Grain maize
363.2 8000 0.15 1200 2421 836.8 209.2
(surface)
Tomato 618.2 14500 0.15 2175 4120 1556 389.2
Cabbage 593.2 23900 0.07 1673 8474 1079.8 270
