Agriculture Reference
In-Depth Information
Table 11.9.
Guidelines for the evaluation of the quality of irrigation water. (Source: Ayers and Westcot, 1987.)
No
problem
Growing
problem
Serious
problem
Salinity
(
EC
w
in dS m
−1
)
<0.7
0.7-3.0
>3.0
Infiltration sodium absorption ratio (SAR)
0-3 and
EC
w
>0.7
0.7-0.2
<0.2
3-6 and
EC
w
>1.2
1.2-0.3
<0.3
6-12 and
EC
w
>1.9
1.9-0.5
<0.5
12-20 and
EC
w
>2.9
2.9-1.3
<1.3
20-40 and
EC
w
>5.0
5.0-2.9
<2.9
Specific ionic toxicity
Sodium (me l
−1
)
Surface irrigation
<3.0
3.0-9.0
>9.0
Sprinkler irrigation
<3.0
>3.0
Chlorides (me l
−1
)
Surface irrigation
<4.0
4.0-10.0
>10.0
Sprinkler irrigation
<3.0
>3.0
Boron (mg l
−1
)
a
<0.7
0.7-3.0
>3.0
Diverse effects
Nitrogen (N in mg l
−1
)
<5.0
5.0-30.0
>30.0
Bicarbonates (me l
−1
) sprinkler irrigation
<1.5
1.5-8.5
>8.5
pH
Normal range 6.5-8.4
a
Values for boron are the same for both surface irrigation and sprinkler irrigation.
the nutrient solution and the water
applications.
The recirculation of the drainage water
and can improve their WUE, but
requires disinfection of the recycled
water to prevent diseases.
Nowadays, the use of fertigation man-
•
in soilless crops (closed systems)
requires the use of good quality water
•
agement computers is expanding.
