Types of irrigation:
- canal and drainage systems - flood fields
- center pivot irrigation, spray vs. drip.
- drip irrigation - direct supply by hoses.
- UNL site on types of irrigation.
- cycles of irrigation and some numbers to
- salinity of seawater: circa 35,000 ppm
- salinity of input irrigation waters 350 ppm.
- >2000 to 3000 ppm toxicity level for many
- critical question: if the climate is arid
enough that water evaporates out of soil where does the salt
- extent of concern?
- San Joaquin valley in California, Pakistan,
"half of the world's irrigated land .... suffers from reduction
of crop yields due to salinization."
- possible solutions:
- desalinize irrigation water (very expensive).
- direct trickle irrigation (water usage reduction).
- tile fields: can flush salts through soil,
but run off waters high in Selenium in California, and expensive.
- salt resistant crops via genetic engineering
(potentially only delay problem).
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