Evaluation of a Center Pivot irrigation system

Here is the evaluation abstract of a central Pivot irrigation System (CPIS), made in Brazil from a technical and economic point of view. The profitability of the system was simulated using real data obtained from a farm located in Chile, projected over a time horizon of ten years.

Internal Rates of Return were estimated on two crops that frequently use CPIS maize for seed and maize-for grain, assuming a decreasing capital allocation and an increasing governmental subsidy, in the terms provided by Chilean Law 18.450.

From a technical standpoint, results showed that the operation parameters agreed with the specifications of the manufacturer. The Hermann and Hein Coefficient of Uniformity obtained was 86%, classifying the area irrigated as «well watered».

The Distribution Uniformity parameter obtained was 79%, an adequate result for the crop and soil conditions of the test.

The Internal Rate of Return obtained for maize for-seed varied from 23% to 103% for the range of 100% to 25% of self-financing.

For the case of maize-for-grain the investment is profitable only with a maximum of 70% of capital allocation from the part of the farmer, implying that the minimum subsidy required from the part of the State is 30%.

Water for farming

Most people may drink only two litres of water a day, but they consume about 3,000 if the water that goes into their food is taken into account. The rich gulp down far more, since they tend to eat more meat, which takes far more water to produce than grains.

So as the world’s population grows and incomes rise, farms will (if they use today’s methods) need a great deal more water to keep everyone fed: 2,000 more cubic kilometres a year by 2030, or over a quarter more than they use today.

Yet in many farming regions, water is scarce and likely to get scarcer as global warming worsens. The world is facing not so much a food crisis as a water crisis.

The solution, is more efficient use of water (Pivot Irrigation Systems) or, "more crop per drop”. Some 1.2 billion people, about a fifth of the world’s population, live in places that are short of water. Farming accounts for roughly 70% of human water consumption.

So when water starts to run out, as is happening in northern China, southern Spain and the western United States, among other places, farming tends to offer the best potential for thrift. But governments, whether to win votes or to protect the poor, rarely charge farmers a market price for water. So they are usually more wasteful than other consumers—even though the value they create from the water is often less than households or industry would be willing to pay for it.