Micah Woods
March 08, 2017
3.3k

# Irrigation water quality

I used these slides for a presentation about irrigation water quality at the Sustainable Turfgrass Management in Asia 2017 conference. I then showed various calculations of the daily soil water balance.

March 08, 2017

## Transcript

1. ### Irrigation water quality Micah Woods 8 March 2017 Chief Scientist

| Asian Turfgrass Center www.asianturfgrass.com

4. ### 1. Salinity and sodium hazard 2. Soil moisture content 3.

Daily soil water balance

10. ### The salt in the water is the most important water

quality parameter.
11. ### Salinity is measured in two ways Total dissolved solids By

evaporating the water, and measuring what remains, one gets total dissolved solids (TDS), reported as mg/L, or ppm.
12. ### Salinity is measured in two ways Electrical conductivity When there

is more salt in the water, it can conduct more electricity. The electrical conductivity (ECw ) is in units of dS/m.

16. ### Salinity is managed by adding more water than the grass

can use or the soil can hold.
17. ### This is called a leaching fraction 2 step process First,

calculate the leaching requirement (LR). Second, calculate the quantity of water to apply. Let's imagine we have a water with a TDS of 1,500 ppm. And we expect the grass to use (ETc ) 4 mm. How much water is required for irrigation?

19. ### Using the leaching requirement After we have the LR, then

we calculate the quantity of water to apply as: irrigation = ETc 1 − LR

= 0.05

= 4.2

23. ### My favorite reference guide about water From Harivandi's Interpreting turfgrass

irrigation water test results

26. ### If there is too much sodium in the irrigation water,

the sodium causes deﬂocculation of the soil clay particles. This is not a problem on sand rootzones.

29. ### Check sodium hazard by SAR Sodium adsorption ratio (SAR) SAR

= Na √ (Ca + Mg)/2

39. ### Know three numbers 1. The volumetric water content (VWC) at

ﬁeld capacity
40. ### Know three numbers 1. The volumetric water content (VWC) at

ﬁeld capacity 2. The VWC at the wilting point
41. ### Know three numbers 1. The volumetric water content (VWC) at

ﬁeld capacity 2. The VWC at the wilting point 3. The VWC now