Conclusions and plans for the coming season
There was greater vigour in the sprinkler irrigated trees under net. The greater leaf cover hinders light penetration and reduces colour development under the lower light situation of netting. This is likely to have caused the difference in colour between the sprinkler irrigated crop and the drip irrigated crop under the net.
Under tree sprinkler irrigation will sustain significant grass cover that requires maintenance during the season, an added cost. It also may reduce the amount of reflected light from the surface, potentially affecting the colour development. Under drip irrigation, less grass cover persists between the rows, a direct result of limiting water to a narrow band around the trees as shown in the images.
While colour was better this season, we hope to improve in the coming season. Due to the reduced water use and vigour and increased colour development under the net using drip irrigation, it is planned to convert the entire netted area to drip for the coming season.
There are benefits to be made from using drip irrigation under the net and possibly outside the netted area, based on this year’s observations. The Lysters, Pomewest and the DAFWA team have also decided that the entire outside netted area will be converted to drip for comparison with under net, with the benefit of still having the under tree sprinklers in extreme heat events and to maintain some ground cover if required.
This work is supported through funding from Royalties for Regions Department of Regional Development, Horticulture Innovation Australia and The Commonwealth Department of Agriculture, Fisheries and Forestry.