Soil moisture management and irrigation
Adequate soil moisture is one of the most important aspects to growing avocados. Getting the balance wrong will lead to restriction of tree performance and possibly a decline in tree health. Each of the main growing regions in New Zealand have different soil types and different rainfall, presenting different challenges for soil moisture management. There is sufficient annual rainfall to meet the needs of the avocado trees in most growing regions however, this rainfall does not always occur consistently throughout the year leading to periods when irrigation can benefit an orchard. In the Far North having an irrigation system is essential due to a lack of rainfall during the summer months and the predominately sandy soil that retains a relatively small amount of water. In the Bay of Plenty irrigation may be less of a necessity due to the predominately loam soils storing a good amount of available water for trees. An irrigation system is still a valuable management tool protecting tree performance against periods of drought and can also be set up to provide frost protection. The purpose of an irrigation system should be to maintain soil moisture levels such that they support maximum plant growth. The key to using irrigation effectively is understanding how water behaves in your soil type and the water requirements of avocado trees. How much to irrigate depends largely on climate, tree maturity, soil type and irrigation capabilities.
For more information on soil moisture, download the soil moisture and irrigation chapter from the grower manual below.