The MPI Sustainable Farming Fund “Smart Tools to Improve Orchard Drainage” project was initiated in response to extreme weather conditions experienced by pipfruit growers in the late season (March – June) harvest of 2017. It is co-funded by New Zealand Apples and Pears Inc.

A survey conducted over 3 weeks in November and December of 2018 covered 2,238 hectares of pipfruit growing orchards. Conducting the survey with growers via face-to-face interviews produced a greater number and depth of answers, however certain details were still difficult to obtain. Many growers were hesitant to provide or lacked confidence in estimations of the extent and area of wheel rut damage as a result of poor drainage.

To help with consistent assessments, we created a four panel photo scale of drainage issues found in orchards (see below). Growers interviewed considered the scale realistic and relevant. They felt able to correctly match problems areas in their blocks to the photos, but differed in their assessments of how much of a problem it might be.

The key impacts on operations identified by the survey were predominantly categorised into three areas; tree health, access, and labour. Almost all orchardists surveyed believed that poor drainage was contributing to poor tree health (either visibly or evident through low yield) or causing tree deaths (up to 10% in one extreme example). Many orchardists remarked on wheel ruts resulting in staff injuries (due to ladder slips in mud, tripping, or the impact of driving over uneven surfaces). Labour availability was also affected in severe cases where orchard ponding and ruts were the reason some contracting groups did not want to work at those sites. In all cases where extreme damage was present, access for sprayers, and tractors hauling harvest bins was impeded, and occasionally impossible. This meant that costs were incurred as a result of delaying harvest windows, slowing the pace of operations, and risking greater levels of disease at an already busy time of year.

Situational factors common among the orchards studied included:

• Frequent passes by heavy orchard machinery for many months of the year (7 – 11)
• Low spots in the in the inter-row were the worst affected
• Shaded canopies associated with 3D training and mature plantings

The area affected was 44% of the area surveyed (1,479 ha).

Tree Health

Tree health suffers as a result of poor drainage and water-logging of the soil. This was evident in the Motueka and Richmond site visits, where trunk diameter was clearly smaller to the untrained eye in low spots where ponding and wheel ruts were severe. The same observations were made during site visits in Nelson and Hawke’s Bay.

Other important comments included a noticeably lower yield from trees where drainage problems were evident, and some bins where mud had covered fruit during harvest resulted in a greater number of fruit rots in post-harvest storage. One grower also mentioned that the fruit on Fuji varieties developed russet in the worst affected areas.

Access to the orchard is critical at certain times to complete operational tasks. Where an orchard has particularly severe drainage problems the wheel ruts may be so extreme that tractor or sprayer axles drag through the mud, meaning that they are stuck or unable to enter the block. This has led to some orchardists hiring helicopters to apply fungicides when application during a specific time window is crucial. This is an expensive exercise, and is unable to be utilised for insecticide sprays, as the application method is not effective at reaching the internal area of the canopy. The mud and ruts from poor drainage make harvesting difficult and time consuming as tractors require towing (by another or multiple tractors) out of the mud when they become stuck.