Introduction

Irrigation assessments are important for ensuring the correct amount of water is applied to avoid yield lose due to moisture stress. However, excessive irrigation is a cause of nitrate leaching. A key aspect of our Future Proofing Vegetable Production project addresses keeping nutrient in the root zone. Through assessing irrigation uniformity and depth applied, machine and irrigation management can be improved.

This work is part of the MPI Sustainable Farming Fund “Future Proofing Vegetable Production” project, co-funded by Horizons Regional Council, Potatoes NZ, Gisborne District Council, Ballance AgriNutrients and LandWISE.

Methodologies

The irrigator assessments followed the ‘bucket test’ protocols as described in the Traveling Irrigator Performance Quick Test. In brief, buckets were place at 1m intervals across the path of the irrigator (see Figure 3). The speed of the irrigator was measured as it travelled over the buckets. Once the irrigator had passed over the buckets, the volume of water collected in each bucket was then measured. The data was entered into IRRIG8Lite software and reports generated.

Results

All three irrigators tested were traveling booms. The performance assessment was carried out twice on one of the traveling booms. An example of the distribution graph is provided in Figure 4. Of the four tests completed, the distribution uniformity assessment for two were ‘adequate’ and two were ‘poor’. The distribution uniformity for the four tests were 0.72 and 0.75 for the ‘adequate’ performing machines and 0.6 and 0.45 for the ‘poor’ performing machines.

Discussion

The results so far show that there is room for improvement in the performance of the irrigators tested so far. Higher than average rainfall has meant irrigation events have not been required as often so far this season. However, some growers briefly ran their irrigators to allow tests to be completed. We will continue to assess irrigators as we are able to access them over the coming months.