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Adjusting Irrigations
Monitor soil moisture before and after irrigation and adjust the maximum irrigation amount if;
- soil is wet below the root-zone or,
- soil is dry after irrigation
Also adjust the Crop Factor (and therefore maximum number of days between irrigations) if;
- soil becomes to dry or,
- remains to wet before a scheduled irrigation
(Source: Guide to best practice water management - orchard crops.)
Scheduling
The recommended irrigation scheduling system will utilise Crop Factors and Evaporation (Epan) or Crop Coefficient and Evapotranspiration (ETo), together with soil moisture monitoring to determine and adjust both the amount and timing of irrigations, A summary of the steps is as follows:
How much to irrigate
Step 1: Determine the irrigated root volume, from;
- the wetting pattern and
- the root distribution
Step 2: Estimate the maximum amount of allowable irrigation, from:
- the irrigated root volume and
- the percentage of RAW
When to irrigate
Step 3: Calculate the maximum number of days allowable between each irrigation for each month of the season based on:
- maximum amount of allowable irrigation, and
- average daily Epan and crop factor or ETo and coefficient
Step 4: Irrigation occurs after the number of days calculated in step 3. with volumes as calculated below.
 | Flood or Knocker Sprinklers | Micro-irrigation |
| Irrigation Requirement (mm) = | Epan (mm) x Crop Factor | Epan (mm) x Crop Factor x Planting (m2) |
OR |
| Irrigation Requirement (mm) = | ETo (mm) x Crop Coefficient | ETo (mm) x Crop Coefficient x Planting (m2) |
(Source: Guide to best practice water management - orchard crops.)
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