Agri-Environmental Management in Europe by Lewis Kathy;Tzilivakis John;Warner Doug;Green Andy; & John Tzilivakis & Doug Warner & Andy Green

Author:Lewis, Kathy;Tzilivakis, John;Warner, Doug;Green, Andy; & John Tzilivakis & Doug Warner & Andy Green
Language: eng
Format: epub
Publisher: 5m Publishing

4.3.2.3. Optimising the performance of irrigation networks

Irrigation has been a feature of agricultural systems around the world since ancient times, with the civilizations of Egypt and Mesopotamia first diverting the annual flood waters of the Nile, Tigris and Euphrates around 8,000 years ago, while in Europe, the Greeks and Romans too made considerable use of irrigation to boost the productivity and reliability of their farming systems and this is still the objective today. Historically, the practice of irrigation has been dominated by the use of surface waters, although ground-water sources were also sometimes tapped, with the main developments being to the way in which water was extracted in order to supply the system (e.g. the shaduf, water wheels, Archimedes screw, etc.). Regardless of the extraction system employed, however, gravity was then used to transport water from its source to the field, via man-made irrigation channels, such that it could be spread over the growing area through a flood- or furrow-based application system, the former being one in which the entire surface of the field is intermittently covered by a layer of anthropogenic flood water, whilst the latter was one in which water was flooded through a series of channels within the field to wet the surrounding soil, this method being more suited to crops grown in defined rows and where the soil has a reasonably high hydraulic conductivity. In more recent times, however, there have been significant developments in the way in which water is transported to and applied to the field, allowing considerably more scope for managing that water use in such a way as to reduce pressure on resources.

The first step needed to optimise the farm’s water network is to determine the most suitable means of transporting water from its point of origin (surface or ground) to its point of use (the field or fields in which the crop is being grown). On a large scale the choice of conveyancing system is likely to be a matter for local and/or national planning authorities rather than individual farmers, but businesses may be faced with a number of options once water reaches their farm, such that a balance needs to be struck between the capital costs involved in implementation, the cost of water, the efficiency with which a given system is likely to operate and the need to maximise efficiency (i.e. are there limits placed on water availability or is water freely available?).

The best way of achieving this will also depend on a number of geospatial factors, including the distance to be covered, the underlying soil, geology and climate. In the UK, for example, water is rarely carried far from its source, often being abstracted on the farm intending to use it. As a result, the most common form of transfer is through temporary or permanent pipework, which, if properly maintained, will minimise losses through leakage, although care needs to be taken to ensure that this occurs in reality. In many parts of Europe, however, open irrigation canals are commonplace, such that losses through leakage and evaporation can be significant.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.