28-06-2012, 04:40 PM
Seminar on Irrigation Water Quality
Irrigation Water Quality.ppt (Size: 5.23 MB / Downloads: 328)
Water salinity
Total salinity
Chloride salinity
Units:
mg/L
ppm
mmhos/cm
mmole/L
Measurements: Evaporation, EC meters
EC: dS/m, mmhos/cm
1dS/m = 640 mg/l
Leaching
Leaching consist of applying irrigation water in excess of the soil moisture depletion level to remove salts from the root zone. The excess water flows down below the root zone, carrying salts with it.
The leaching requirement is the leaching fraction (the amount of excess water) needed to keep the root zone salinity level within that tolerated by the crop. This requirement is determined by the crop`s tolerance to salinity and by the salinity of the irrigation water.
This excess, water expressed as a percent of the applied irrigation water, is the leaching fraction.