Above a certain capacity, the incremental yield benefits of irrigation decrease with increasing irrigation system capacity. Production per unit of water used is an easy way of indicating whether irrigation and rainfall are being used efficiently, and can be used to compare the total water use from season to season. However, this indicator needs to be reported for each crop because different crops have different water requirements and responses to water. To assess the effect of irrigation on individual crops, the quantity of each type of crop produced should be recorded, and compared with the irrigation water applied to the crop. The recommended indicators will be ideal for inter-farm comparisons, to give an indication of the most effective systems.
Aggregation can result in production figures for an entire region or scheme.
Energy, water and labour figures are readily available to the farmer through accounting records, power bills and timesheets. Production quantity and quality data can also be determined from crop records and sales information.