Irrigation recommendations
The following irrigation recommendations have been produced using long term average evaporation and rainfall data for three locations in the south west of WA.
The suggested irrigation rates will need to be adjusted through the season to account for daily evaporation and rainfall.
Soil moisture sensors and tree growth should be used to provide information on how this irrigation plan is performing. It is likely that the suggested irrigation rates shown below will be modified as new information on the irrigation requirements of jujubes in WA becomes available.
The amount of irrigation required has been calculated using the Irrigation Calculator. The program uses crop factors for each month of the year to replace a percentage of the effective evaporation.
The literature states that jujubes, when grown to achieve high yields, require similar rates of irrigation to other deciduous fruit trees. Transpiration and the amount of irrigation required is proportional to the area of leaf on the tree. In the tables below the percentage of the orchard floor (as viewed from above) covered by leaves is used to approximate this. When estimating the water requirements of trees that are grown on a trellis the percentage of orchard floor figure will have to be increased to account for the vertical rather than horizontal orientation of the foliage.
The crop factors used for jujubes are shown in the table below. You can see that the crop factors (or percentage of evaporation that is replaced) is decreased at the end of February. This is reduced as less water is required after harvest. If the trees are in the south of the state and harvest is after the end of February then the rate of irrigation should be maintained at the February level until harvest is complete.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.5 | 0.5 | 0.3 | 0.3 | 0.1 | 0.1 | 0.1 | 0.1 | 0.3 | 0.6 | 0.8 | 0.8 |
Irrigation recommendations are given both as cubic metres per hectare (same as kilolitres/hectare) and litres per tree for each month of the year. The daily irrigation rate can be calculated by dividing the monthly rate by the number of days in the month.