Irrigation

Comparing irrigation types

Decision making on types of irrigation to use is not always straight forward. Capital cost, water and land scarcity, land tenure, water right security, investment and labor availability must be considered. There are many misconceptions about water use efficiency. Flood irrigation is often maligned as "wasteful" (especially by irrigation system salespeople) when in most cases it uses the least energy and materials of any option, and frequently results in many external ecosystem and downstream benefits, such as recharging aquifers and wells and promoting healthy, perennial streams. See also Defining efficiency in water usage and In defense of flood irrigation

Surface Irrigation

Also called "flood Irrigation" using pipe systems, ditch systems or vinyl pipe

Paddy irrigation

http://i.imgur.com/1TBdaHv.gifv

benefits

replenishing groundwater

Defining efficiency in water usage

When it comes to irrigation water, efficiency is often thought of as minimizing use of water at all costs. However, in a regenerative agriculture system, the definition of efficiency must be more holistically derived. Efficiency in using every available drop of water to grow crops regardless of the cost in energy, capital and labor can be a destructive and non-regenerative task which can ultimately result in destruction of eco-systems (by diversion of rivers or springs or lowering a water table by pumping for example), pollution and a waste of energy.

To define efficiency we must begin with an understanding of a system's limitations. It's often useful to do an audit, or calculation of the final cost/benefit ratio of an agricultural system in terms of the energy, labor, water and capital (in both materials and financial resources) required and the value of the crop produced in both economic and nutritional terms.

Drip irrigation systems are frequently spoken of as "highly efficient" because of the low throughput of water required to raise a crop. But they can be characterized as highly inefficient in terms of materials (lots of plastic pipe and fittings are needed and the need to be frequently replaced), energy (pumps must push the water through filers and networks of pipe with high friction losses) and labor (installation and maintenance labor as well as additional labor for hand weeding where mechanical weeding would interfere with pipes.

Where labor AND capital are plentiful but water is scarce and there is a great demand for fresh vegetables, places like Israel/Palestine or Arizona for example, it may be worth considering drip irrigation. However even in these situations, energy and materials usage as well as impact to the local ecosystem and financial cost of a proposed agricultural system might mean that it would actually be better to transport vegetables from a region with a lower impact to raising vegetables, or indicate that the local diet and population base is not sustainable in that environment. A holistic cost/benefit analysis of using systems like drip irrigation may produce surprising results to people who assume that those systems are the "most efficient"

Drip irrigation example Farmer Cultivation Center, Niwot Colorado

(after describing the system in use - omit the name)