Near Infrared Technology— getting up to speed

During the recent International Mango Symposium held in Darwin, Kerry Walsh from Central Queensland University held a masterclass on non-invasive technologies to assess quality. Kerry and research officer, Phul Subedi, have been working with NIR technology in the mango industry for several years.

During the recent International Mango Symposium held in Darwin, Kerry Walsh from Central Queensland University held a masterclass on non-invasive technologies to assess quality. Kerry and research officer, Phul Subedi, have been working with NIR technology in the mango industry for several years.

The masterclass involved demonstration and handling of a range of monitoring and measurement equipment. While a focus was given to the non-invasive in-field assessment of fruit dry matter content using a handheld spectrometer, a range of other equipment was also presented, including: temperature and light data loggers, soil moisture loggers, leaf area analyser, plant canopy area analyser, root density camera, ethylene analyser and fruit penetrometer.
During the year, due to the manufacturer being unable to supply further ‘Nirvana’ NIR units, there has been a transition to the Felix Instruments ‘F750’. To support this transition, Ryan Lerud of Felix Instruments attended the Mango symposium to address any questions about the new units. Early in the season, Kerry, Phul and Nick Anderson, CQ University Masters student worked with growers in the Darwin region on calibrating the new units and developing better systems to support the technology.

Some of the research being undertaken includes:

  • Research on water denial, investigating water as a tool to influence fruit dry matter content and final ripe Brix.
  • Investigating the NDVI index and matching it with on ground agronomic information. NDVI stands for Normalized Difference Vegetation Index and is an index of plant “greenness” or photosynthetic activity, and is one of the most commonly used vegetation indices.
  • Work is also underway to better and more easily display dry matter (DM) information collected with the F750. The concept Kerry’s team is working towards involved a Bluetooth transfer of data from the handheld unit to a PC, followed by automated upload to a web based system, with display of sampling points (see figure), automated association of measurements to user defined blocks of trees and display of mean DM or DM change over weeks.