Endurance.Net Ridecamp Archives

> ..without getting into the specifics, if anyone wants to learn=
>  more about the dangers of gravity flow irrigation on our crops, check out =
> what happened in the central valley of CA in the 80's. The same high levels=
>  of selenium, sodium, and trace minerals that caused serious birth defects =
> in the birds of the Kesterson Resevoir left the rich soil of the valley, es=
> pecially the western side, severely depleted.

This is more a function of soil substrate and drainage issues, not the type of irrigation applied.

http://sfep.abag.ca.gov/reports/fact/agdrain.html

Any arid/saline soil needs to have sufficient water applied to move salts below root level - really doesn't matter if you do it by flooding, sprinklers or drip - you still need a certain amount of water and, if drainage conditions are poor, you'll have results like the above - accumulation of salts and trace elements in runoff. 

Patti K

Vail AZ