Irrigation technology:
A separate pop-up page provide editing possibilities for the irrigation technology specific parameters.
They define the efficiency, losses, but also the constraints for scheduling,
of a set of alternative irrigation technologies.
These include:
- Technology Name, for identification purpose;
- Loss (in %, defining the application efficiency; loss describes the % of water allocated to
a field, but not effectively available for the crop;
the loss is attributed to the groundwater (and an eventual drainage return flow)
and assumed not to be available to the plants),
- Application target (daily) in % of the range of soil moisture between
field capacity (saturation) to the current MAD;
- An application target of 100 % will attempt to raise the soil moisture to field
capacity, subject to the maximum daily technology specific application
rate or flow constraint (see below);
- An application target of 0% will raise the soil moisture only to the current MAD.
- An application target of 50% will raise the soil moisture halfway between MAD and field capacity (saturation);
The higher the target, the fewer irrigation events will be needed (unless it rains ...);
a low value will lead to more frequent but shorter (smaller) irrigation events,
a higher target to fewer but longer irrigation events.
- MR, maximum daily application rate (in mm) as an explicit constraint on the
conveyance (flow) capacity of a given technology.
- DP, Deep percolation, which defines the fraction (%) of seepage (loss, that is any water above field capacity)
that percolates into deep groundwater, and is not contributing to the drainage (return) flow
portion of the water budget.
This fraction of the losses however depends on drainage characteristics rather than irrigation technology.
|
irrigation technology |
loss |
target |
MR |
DP (%) |
Flooding (conventional furrow; surge flow furrow; border strip) |
50 |
100 |
500 |
15 |
Sprinkler MID (mid--elevation spray center pivot;) |
30 |
75 |
250 |
15 |
Sprinkler LOW (low-elevation spray center pivot;) |
20 |
50 |
100 |
15 |
Sprinkler LEPA (low energy precision application center pivot) |
15 |
50 |
75 |
15 |
Drip, manual |
5 |
20 |
50 |
15 |
Drip, electronic |
0 |
10 |
50 |
15 |
Paddy cultivation |
10 |
100 |
250 |
5 |
|
|